The 100 most-cited articles in Analytical Chemistry, 2024

High Resolution Image Download MS PowerPoint Slide Rapid and accurate detection of human epidermal growth factor receptor 2 (HER2) is crucial for the early diagnosis and prognosis of breast cancer. In this study, we reported an iron–manganese ion N-doped carbon single-atom catalyst (FeMn-NC etch /SAC) bimetallic peroxidase mimetic enzyme with abundant active sites etched by H 2 O 2 and further demonstrated unique advantages of single-atom bimetallic nanozymes in generating hydroxyl radicals by density functional theory (DFT) calculations. As a proof of concept, a portable device-dependent electrochemical-photothermal bifunctional immunoassay detection platform was designed to achieve reliable detection of HER2. In the enzyme-linked reaction, H 2 O 2 was generated by substrate catalysis via secondary antibody-labeled glucose oxidase (GOx), while FeMn-NC etch /SAC nanozymes catalyzed the decomposition of H 2 O 2 to form OH*, which catalyzed the conversion of 3,3′,5,5′-tetramethylbenzidine (TMB) to ox-TMB. The ox-TMB generation was converted from the colorimetric signals to electrical…

Pressure and temperature, as common physical parameters, are important for monitoring human health. In contrast, single-mode monitoring is prone to causing experimental errors. Herein, we innovatively designed a dual-mode flexible sensing platform based on a platinum/zinc-meso-tetrakis(4-carboxyphenyl)porphyrin (Pt/Zn-TCPP) nanozyme for the quantitative monitoring of carcinoembryonic antigen (CEA) in biological fluids with pressure and temperature readouts. The Pt/Zn-TCPP nanozyme with catalytic and photothermal efficiencies was synthesized by means of integrating photosensitizers into porous materials. The flexible sensing system after the antigen–antibody reaction recognized the pressure using a flexible skin-like pressure sensor with a digital multimeter readout, whereas the temperature was acquired via the photoheat conversion system of the Pt/Zn-TCPP nanozyme under 808 nm near-infrared (NIR) irradiation using a portable NIR imaging camera on a smartphone. Meanwhile, the dual-mode flexible sensing system was carried out on a homemade three-dimensional (3D)-printed device.…

Different from prevalent approaches such as immunological recognition, complementary base pairing, or enzymatic regulation in current photoelectrochemical (PEC) sensing, this study reported an excited-state intramolecular proton transfer (ESIPT)-driven photon-gating PEC sensor. The sensor is developed for the detection of CO-releasing molecule-3 (CORM-3) by modifying an ESIPT-switched organic fluorescent probe molecule (NDAA) onto the surface of a p-type semiconductor (BiOI). The NDAA can be excited and exhibit strong green fluorescence after responding with CORM-3, resulting in an electrode-interface photon competitive absorption effect due to the switch on ESIPT and considerably reducing the photocurrent signal. The experimental results revealed that the as-developed PEC sensor achieved good analytical performance with high selectivity and sensitivity, with a linear range of 0.01-1000 μM and a lower detection limit of 6.5 nM. This work demonstrates the great potential of the organic fluorescent probe molecule family in advancing PEC analysis. It is anticipated that our findings…

Wearable, noninvasive sensors enable the continuous monitoring of metabolites in sweat and provide clinical information related to an individual ’ s health and disease states. Uric acid (UA) is a key indicator highly associated with gout, hyperuricaemia, hypertension, kidney disease, and Lesch–Nyhan syndrome. However, the detection of UA levels typically relies on invasive blood tests. Therefore, developing a wearable device for noninvasive monitoring of UA concentrations in sweat could facilitate real-time personalized disease prevention. Here, we introduce 1,3,6,8-pyrene tetrasulfonic acid sodium salt (PyTS) as a bifunctional molecule functionalized with Ti 3 C 2 T x via π–π conjugation to design nonenzymatic wearable sensors for sensitive and selective detection of UA concentration in human sweat. PyTS@Ti 3 C 2 T x provides many oxidation–reduction active groups to enhance the electrocatalytic ability of the UA oxidation reaction. The PyTS@Ti 3 C 2 T x -based electrochemical sensor demonstrates highly sensitive detection of UA in the concentration range of 5 μM–100 μM, exhibiting…

Compared with traditional "lock-key mode" biosensors, a sensor array consists of a series of sensing elements based on intermolecular interactions (typically hydrogen bonds, van der Waals forces, and electrostatic interactions). At the same time, sensor arrays also have the advantages of fast response, high sensitivity, low energy consumption, low cost, rich output signals, and imageability, which have attracted widespread attention from researchers. Nanozymes are nanomaterials which own enzyme-like properties. Because of the adjustable activity, high stability, and cost effectiveness of nanozymes, they are potential candidates for construction of sensor arrays to output different signals from analytes through the chemoresponse of colorants, which solves the shortcomings of traditional sensors that they cannot support multiple detection and lack universality. Recently, a sensor array based on nanozymes as nonspecific recognition receptors has attracted much more attention from researchers and has been applied to precise recognition of proteins, bacteria, and heavy metals. In this…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTChallenges and Advances of Hydrogel-Based Wearable Electrochemical Biosensors for Real-Time Monitoring of Biofluids: From Lab to Market. A ReviewHossein ChenaniHossein ChenaniDepartment of Materials Science and Engineering, Sharif University of Technology, 14588 89694 Tehran, IranMore by Hossein ChenaniView Biographyhttps://orcid.org/0009-0009-6924-6491, Mohsen Saeidi*Mohsen SaeidiDepartment of Materials Science and Engineering, Sharif University of Technology, 14588 89694 Tehran, Iran*Tel: +98-21-6616 5262; Fax: +98-21-6600 5717; Email: [email protected]More by Mohsen SaeidiView Biographyhttps://orcid.org/0000-0001-5430-3339, MahsaSadat Adel RastkhizMahsaSadat Adel RastkhizDepartment of Materials Science and Engineering, Sharif University of Technology, 14588 89694 Tehran, IranMore by MahsaSadat Adel RastkhizView Biographyhttps://orcid.org/0009-0002-6628-6868, Nafiseh BolghanabadiNafiseh BolghanabadiDepartment of Materials Science and Engineering, Sharif University of Technology, 14588 89694 Tehran, IranMore by Nafiseh BolghanabadiView…

Molecular imprinting-based surface-enhanced Raman scattering (MI-SERS) sensors have shown remarkable potential from an academic standpoint. However, their practical applications, especially in the detection of large-size protein (≥10 nm), face challenges due to the lack of versatile sensing strategies and nonspecific fouling of matrix species. Herein, we propose a Raman reporter inspector mechanism (RRIM) implemented on a protein-imprinted polydopamine (PDA) layer coated on the SERS active substrate. In the RRIM, after large-size protein recognition, the permeability of the PDA imprinted cavities undergoes changes that are scrutinized by Raman reporter molecules. Target proteins can specifically bind and fully occupy the imprinted cavities, whereas matrix species cannot. Then, Raman reporter molecules with suitable size are introduced to serve as both inspectors of the recognition status and inducers of the SERS signal, which can only penetrate through the vacant and nonspecifically filled cavities. Consequently, changes in the SERS signal exclusively originate from the specific…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTRecent Advances in Photoelectrochemical Sensing for Food SafetyYuanxing ChenYuanxing ChenHubei Key Laboratory of Plasma Chemistry and Advanced Materials, Hubei Engineering Technology Research Center of Optoelectronic and New Energy Materials, Wuhan Institute of Technology, Wuhan 430205, P. R. ChinaState Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. ChinaMore by Yuanxing ChenView Biography, Wenling GuWenling GuState Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. ChinaMore by Wenling GuView Biographyhttps://orcid.org/0000-0003-4926-5993, Chengzhou Zhu*Chengzhou ZhuState Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensing Technology and Health, College of Chemistry, Central China Normal University, Wuhan…

Photoelectrochemical (PEC) sensing mechanisms based on enzyme-catalyzed strategies primarily achieve the quantitative analysis of biomolecules through the enhancement or attenuation of photocurrent signals. However, there are still no reports that delve into the principles of photocurrent signaling conversion in the reaction between photoactive materials and the biomolecules. In this work, we demonstrated that indium oxysulfide InOS-0.5 heterojunction has excellent peroxidase activity to catalyze the reaction of H 2 O 2 -generated hydroxyl radicals ( • OH) with the self-generated electrons, thereby resulting in synergistic quenching of the photocurrent signal. Based on the above principles, we coupled InOS-0.5 with a sandwich-type immunoassay to introduce H 2 O 2 production catalyzed by glucose oxidase for the development of a PEC immunosensing platform. H 2 O 2 reacted with InOS-0.5 to produce • OH with strong oxidizing properties, thus quenching the photogenerated electrons and realizing the PEC detection of the carcinoembryonic antigen (CEA, as a model analyte). The photocurrent…

Designing a metal–organic framework (MOF)-derived nanozyme with highly dispersed active sites and high catalytic activity as well as robust structure for colorimetric biosensing of diverse biomolecules remains a substantial challenge. Here, an MOF-derived highly dispersed and pure α-cobalt confined in a nitrogen-doped carbon nanofiber (α-Co@NCNF) nanozyme with superior glucose oxidase (GOD)- and peroxidase (POD)-like activities was constructed for colorimetric assay of multiple biomolecules. Specifically, the α-Co@NCNF nanozyme was synthesized, utilizing in situ electrospinning Co-MOFs into polyacrylonitrile nanofiber (PAN) followed by a pyrolysis process. Taking advantage of the in situ electrospinning strategy, the α-Co nanoparticles were confined in continuous porous NCNF to restrict the growth and prevent the aggregation and oxidation during the pyrolysis process. The resulting special structure considerably improved the enzyme-like performance. A series of experiments validate that the enzyme-like activity of the α-Co@NCNF nanozyme was superior to that of Co@CoO@NCNF…

Water microdroplets are widespread in the atmosphere. We report a striking observation that micron-sized water droplets obtained from zero-volt spray sources (sonic spray, humidifier, spray bottle, steamer, etc.) spontaneously generate nitrogen oxides. The mechanistic investigation through the development of custom-designed sampling sources combined with mass spectrometry and isotope labeling experiments confirmed that air nitrogen reacts with the water at the air–water interface, fixing molecular nitrogen to its oxides (NO, NO 2, and N 2 O) and acids (HNO 2 and HNO 3 ) at trace levels without any catalyst. These reactions are attributed to the consequence of an experimentally detected feeble corona discharge (breakdown of air) at the air–water interface, likely driven by the high intrinsic electric field at the surface of water microdroplets. The extent of this corona discharge effect varies depending on the pH, salinity/impurity, size, speed, and lifetime of microdroplets in the air. Thus, this study discloses that the air–water interface of microdroplets breaks the strong…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTWater Analysis: Emerging Contaminants and Current IssuesSusan D. Richardson*Susan D. RichardsonDepartment of Chemistry and Biochemistry, University of South Carolina, JM Palms Center for GSR, 631 Sumter Street, Columbia, South Carolina 29208, United States*[email protected]More by Susan D. RichardsonView Biographyhttps://orcid.org/0000-0001-6207-4513 and Tarek ManasfiTarek ManasfiEawag, Environmental Chemistry, Uberlandstrasse 133, Dubendorf 8600, SwitzerlandMore by Tarek ManasfiView BiographyCite this: Anal. Chem. 2024, 96, 20, 8184–8219Publication Date (Web):May 3, 2024Publication History Received16 March 2024Accepted16 April 2024Revised14 April 2024Published online3 May 2024Published inissue 21 May 2024https://pubs.acs.org/doi/10.1021/acs.analchem.4c01423https://doi.org/10.1021/acs.analchem.4c01423review-articleACS PublicationsCopyright © 2024 American Chemical SocietyRequest reuse permissionsArticle Views826Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since…

Inspired by natural DNA networks, programmable artificial DNA networks have become an attractive tool for developing high-performance biosensors. However, there is still a lot of room for expansion in terms of sensitivity, atom economy, and result self-validation for current microRNA sensors. In this protocol, miRNA-122 as a target model, an ultrasensitive fluorescence (FL) and photoelectrochemical (PEC) dual-mode biosensing platform is developed using a programmable entropy-driven circuit (EDC) cascaded self-feedback DNAzyme network. The well-designed EDC realizes full utilization of the DNA strands and improves the atomic economy of the signal amplification system. The unique and rational design of the double-CdSe quantum-dot-released EDC substrate and the cascaded self-feedback DNAzyme amplification network significantly avoids high background signals and enhances sensitivity and specificity. Also, the enzyme-free, programmable EDC cascaded DNAzyme network effectively avoids the risk of signal leakage and enhances the accuracy of the sensor. Moreover, the introduction of…

Hypochlorous acid (HClO) is a typical endogenous ROS produced mainly in mitochondria, and it has strong oxidative properties. Abnormal HClO levels lead to mitochondrial dysfunction, strongly associated with various diseases. It has been shown that HClO shows traces of overexpression in cells of both ferroptosis and hepatocellular carcinoma (HCC). Therefore, visualization of HClO levels during ferroptosis of HCC is important to explore its physiological and pathological roles. So far, there has been no report on the visualization of HClO in ferroptosis of HCC. Thus, we present a ratiometric near-infrared (NIR) fluorescent probe Mito-Rh-S which visualized for the first time the fluctuation of HClO in mitochondria during ferroptosis of HCC. Mito-Rh-S has an ultrafast response rate (2 s) and large emission shift (115 nm). Mito-Rh-S was constructed based on the PET sensing mechanism and thus has a high signal-to-noise ratio. The cell experiments of Mito-Rh-S demonstrated that Fe 2+ - and erastin-induced ferroptosis in HepG2 cells resulted in elevated levels of mitochondrial HClO and that…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTEvolution of Green Sample Preparation: Fostering a Sustainable Tomorrow in Analytical SciencesH. Martínez-Pérez-CejuelaH. Martínez-Pérez-CejuelaDepartment of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United StatesMore by H. Martínez-Pérez-CejuelaView Biographyhttps://orcid.org/0000-0002-6456-0846 and E. Gionfriddo*E. GionfriddoDepartment of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, United States*[email protected]More by E. GionfriddoView Biographyhttps://orcid.org/0000-0002-1836-1950Cite this: Anal. Chem. 2024, 96, 20, 7840–7863Publication Date (Web):April 30, 2024Publication History Received11 March 2024Accepted22 April 2024Revised20 April 2024Published online30 April 2024Published inissue 21 May 2024https://pubs.acs.org/doi/10.1021/acs.analchem.4c01328https://doi.org/10.1021/acs.analchem.4c01328review-articleACS PublicationsCopyright © 2024 American Chemical SocietyRequest reuse permissionsArticle…

The proteome, or collection of proteoforms expressed in a biological system, is dynamic and heterogeneous. As our appreciation for the complexity of the proteome has evolved, so have the technologies we use to interrogate its composition. More than three decades ago, a rapid expansion in the field of proteomics was driven by the advent of soft ionization techniques focusing on capturing protein sequence information using mass spectrometry (MS). As tools to automate peptide and protein sequencing with tandem MS (MS/MS) matured, our field recognized the limits of qualitatively cataloguing gene products. This realization drove a multi-pronged expansion of MS-centric technologies that seek to capture various aspects of proteins, including their abundance, modification states, conformation and structure, and spatiotemporal relationships. Here we review innovations in MS-based instrumentation that continue to expand our ability to survey the proteome with ever increasing sensitivity, speed, and flexibility. The march of progress in MS instrumentation has been steady over the better half…

Interpretability is just as important as accuracy when it comes to complex models, especially in the context of deep learning models. Explainable artificial intelligence (XAI) approaches have been developed to address this problem. The literature on XAI for spectroscopy mainly emphasizes independent feature analysis with limited application of zone analysis. Individual feature analysis methods, such as shapley additive explanations (SHAP) and local interpretable model-agnostic explanations (LIME), have limitations due to their dependence on perturbations. These methods measure how AI models respond to sudden changes in the individual feature values. While they can help identify the most impactful features, the abrupt shifts introduced by replacing these values with zero or the expected ones may not accurately represent real-world scenarios. This can lead to mathematical and computational interpretations that are neither physically realistic nor intuitive to humans. Our proposed method does not rely on individual disturbances. Instead, it targets "spectral zones" to directly estimate…

In this study, we developed ratiometric surface-enhanced Raman scattering (SERS) biosensors using Ag–Au alloy nanoflowers as SERS substrates, molecules having amide bonds and alkyne groups (Tag A) as Raman reporters, and sodium thiocyanate as an internal standard molecule (Tag B) for the sensitive detection of human carboxylesterase-1 (hCE1) in HepG-2 cells. The correlation between HepG-2 cell damage and hCE1 activity levels was investigated. Both Tag A’s alkyne group and Tag B’s cyanide group produced characteristic SERS signals in the Raman-silent region ( I 2000 cm –1 and I 2115 cm –1, respectively). The hydrolysis of the amide bond in Tag A via hCE1 and the shedding of the alkyne group led to a reduction in the SERS signal intensity observed at I 2000 cm –1 . Conversely, the SERS signal intensity of Tag B at I 2115 cm –1 exhibited a consistent pattern. As the activity level of hCE1 and the ratiometric peak intensity ( I 2000 cm –1 / I 2115 cm –1 ) correlated negatively, hCE1 could be quantitatively detected within the range of 10 –2 to 2 × 10 2 ng·mL –1, with a detection limit…

The 2019 coronavirus disease (COVID-19) outbreak created an unprecedented need for rapid, sensitive, and cost-effective point-of-care diagnostic tests to prevent and mitigate the spread of the SARS-CoV-2 virus. Herein, we demonstrated an advanced lateral flow immunoassay (LFIA) platform with dual-functional [colorimetric and surface-enhanced Raman scattering (SERS)] detection of the spike 1 (S1) protein of SARS-CoV-2. The nanosensor was integrated with a specially designed core-gap-shell morphology consisting of a gold shell decorated with external nanospheres, a structure referred to as gold nanocrown (GNC), labeled with a Raman reporter molecule 1,3,3,1',3',3'-hexamethyl-2,2'-indotricarbocyanine iodide (HITC) to produce a strong colorimetric signal as well as an enhanced SERS signal. Among the different plasmonics-active GNC nanostructures, the GNC-2 morphology, which has a shell decorated with an optimum number and size of nanospheres, produces an intense dark-blue colorimetric signal and ultrahigh SERS signal. The limit of detection (LOD) of the S1 protein via colorimetric…

As a natural green catalyst, laccase has extensive application in the fields of environmental monitoring and pollutant degradation. However, susceptibility to environmental influences and poor reusability seriously hinder its application. To address these concerns, for the first time, manganese ion replaced copper ion as the active center to coordinate with guanosine monophosphate (GMP) for synthesizing mimic laccase with high catalytic activity. Compared with natural laccase, the laccase-like nanozyme (Mn-GMPNS) demonstrated superior thermal stability, acid-base resistance, salt tolerance, reusability, and substrate universality. Benefiting from the high catalytic activity of Mn-GMPNS, epinephrine, a significant neurotransmitter and hormone associated with numerous diseases, was visually detected within 10 min and a portable assay by smartphone. More encouragingly, Mn-GMPNS can efficiently degrade dye pollutants, achieving a decolorization rate over 70% within 30 min. Thus, the coordination between manganese ion and nucleotide demonstrated the potential in rational design of…

In vitro transcription (IVT) of mRNA is a versatile platform for a broad range of biotechnological applications. Its rapid, scalable, and cost-effective production makes it a compelling choice for the development of mRNA-based cancer therapies and vaccines against infectious diseases. The impurities generated during mRNA production can potentially impact the safety and efficacy of mRNA therapeutics, but their structural complexity has not been investigated in detail yet. This study pioneers a comprehensive profiling of IVT mRNA impurities, integrating current technologies with innovative analytical tools. We have developed highly reproducible, efficient, and stability-indicating ion-pair reversed-phase liquid chromatography and capillary gel electrophoresis methods to determine the purity of mRNA from different suppliers. Furthermore, we introduced the applicability of microcapillary electrophoresis for high-throughput (<1.5 min analysis time per sample) mRNA impurity profiling. Our findings revealed that impurities are mainly attributed to mRNA variants with different poly(A) tail…

In this Letter, a sensitive DNA sensing platform was developed using an indium-ion-coordinated 1,1,2,2-tetra(4-carboxylphenyl)ethylene (TPE) metal-organic gel (In-MOG) as an aggregation-induced electrochemiluminescence (AIECL) emitter and nanosurface energy transfer (NSET) as an efficient quenching strategy for detecting aflatoxin B1 (AFB1), the most dangerous food toxin. The coordination occurred in indium ions, and carboxyl groups restricted the internal rotation and vibration of TPE molecules, forcing them to release photons via radiative transitions. The quenchers of microfluidic-produced gold nanoparticles were embedded in a long-tailed triangular DNA structure, where the quenching phenomenon aligned with the theory of ECL-NSET under the overlap of spectra and appropriate donor-acceptor spacing. The proposed analytical method showed a sensitive ECL response to AFB1 in the wide concentration range of 0.50-200.00 ng/mL with a limit of detection of 0.17 ng/mL. Experimental results confirmed that constraining luminescent molecules using coordination and bonding to trigger the AIECL…

Despite growing ecological concerns, studies on microplastics and nanoplastics are still in their initial stages owing to technical hurdles in analytical techniques, especially for nanoplastics. We provide an overview of the general attributes of micro/nanoplastics in natural environments and analytical techniques commonly used for their analysis. After demonstrating the analytical challenges associated with the identification of nanoplastics due to their distinctive characteristics, we discuss recent technological advancements for detecting nanoplastics.

Improving the sensitivity in electrochemiluminescence (ECL) detection systems necessitates the integration of robust ECL luminophores and efficient signal transduction. In this study, we report a novel ECL nanoprobe (Zr-MOF) that exhibits strong and stable emission by incorporating aggregation-induced emission ligands into Zr-based metal–organic frameworks (MOFs). Meanwhile, we designed a high-performance signal modulator through the implementation of a well-designed controlled release system with a self-on/off function. ZnS quantum dots (QDs) encapsulated within the cavities of aminated mesoporous silica nanoparticles (NH 2 –SiO 2 ) serve as the ECL quenchers, while adenosine triphosphate (ATP) aptamers adsorbed on the surface of NH 2 –SiO 2 through electrostatic interaction act as “gatekeepers.” Based on the target-triggered ECL resonance energy transfer between Zr-MOF and ZnS QDs, we establish a coreactant-free ECL aptasensor for the sensitive detection of ATP, achieving an impressive low detection limit of 0.033 nM. This study not only demonstrates the successful combination of…

In clinical diagnostics, sensitive and accurate biomarker monitoring is greatly challenged by the limitations of false positive/negative errors in single-modal photoelectrochemical analysis. Herein, we propose a multimode immunoassay by integrating photoelectrochemical, colorimetric, and photothermal imaging analysis into one electrode. The immunosensors could simultaneously achieve three detection modes at one electrode, which provided a new pathway for the accurate detection of the target prostate-specific antigen (PSA) and circumvented false-positive or negative errors during the detection process. To this end, an integrated multifunctional chip (TiO 2 /ZIF-8/Cu(II)) was first constructed via in situ embedding of Cu(II) in the Metal–organic framework growth process. Then, an alkaline phosphatase-labeled magnetic probe was designed to achieve split-type detection for PSA. In a sodium thiophosphate solution, the in situ generated H 2 S could react with Cu(II) to form small-size CuS due to the nanoconfinement of ZIF-8 and thus result in the formation of p–n heterojunctions (TiO 2…

How timely identification and determination of pathogen species in pathogen-contaminated foods are responsible for rapid and accurate treatments for food safety accidents. Herein, we synthesize four aggregation-induced emissive nanosilicons with different surface potentials and hydrophobicities by encapsulating four tetraphenylethylene derivatives differing in functional groups. The prepared nanosilicons are utilized as receptors to develop a nanosensor array according to their distinctive interactions with pathogens for the rapid and simultaneous discrimination of pathogens. By coupling with machine-learning algorithms, the proposed nanosensor array achieves high performance in identifying eight pathogens within 1 h with high overall accuracy (93.75–100%). Meanwhile, Cronobacter sakazakii and Listeria monocytogenes are taken as model bacteria for the quantitative evaluation of the developed nanosensor array, which can successfully distinguish the concentration of C. sakazakii and L. monocytogenes at more than 10 3 and 10 2 CFU mL –1, respectively, and their mixed samples at 10 5…

In this work, a novel nanozyme (Cu@Zr) with all-in-one dual enzyme and fluorescence properties is designed by simple self-assembly. A nanozyme cascade sensor with disodium phenyl phosphate (PPDS) as substrate was first established by exploiting the dual enzymatic activities of phosphatase and laccase. Specifically, phosphatase cleaves the P–O bond of PPDS to produce colorless phenol, which is then oxidized by laccase and complexed with the chromogenic agent 4-aminoantipyrine (4-AP) to produce red quinoneimine (QI). Strikingly, the NH 3 produced by the urease hydrolysis of urea can interact with Cu@Zr, accelerating the electron transfer rate and ultimately leading to a significantly improved performance of the cascade reaction. Moreover, the fluorescence at 440 nm of Cu@Zr is further quenched by the inner filter effect (IFE) of QI. Thus, the colorimetric and fluorescence dual-mode strategy for sensitive urease analysis with LODs of 3.56 and 1.83 U/L was established by the proposed cascade sensor. Notably, a portable swab loaded with Cu@Zr was also prepared for in situ urease…

Surface-enhanced Raman spectroscopy (SERS), with molecular fingerprint information and single-molecule sensitivity, has been widely used for qualitative and quantitative analysis in various fields. Plenty of nanostructured plasmonic materials have been fabricated to achieve high SERS activity. Currently, great difficulty lies in evaluating the SERS performance among substrates, making it difficult to standardize. Addressing this problem, this work proposed the SERS performance factor ( S P F = Δ I S E R S Δ C S E R S / Δ I R a m a n Δ C R a m a n ) as a practically operational parameter to evaluate the sensitivity of SERS substrates. Experimentally, SPF can be obtained by taking the ratio of the slopes (i.e., the sensitivity) for concentration-dependent SERS and normal Raman measurements in the linear range of the intensity response under identical experimental conditions. Theoretically, SPF quantitatively describes the overall contribution to the SERS performance, (i.e., the electromagnetic (EM) enhancement of the SERS substrate and the interfacial interaction between the probe and…

Herein, we, for the first time, synthesize silver nanoparticles (Ag NPs) within the nanochannels of amino group-functionalized vertically ordered mesoporous silica films (NH 2 –VMSF) and investigate their coreaction accelerator role in the luminol-dissolved oxygen (O 2 ) electrochemical stripping chemiluminescence (ESCL) system. The synthesized Ag NPs are capable of electrocatalytic reduction of O 2 to superoxide radicals, and meanwhile, sliver ions (Ag + ) electrochemically stripped from Ag NPs can promote the amount of luminol anion radicals, generating the boosted ECL intensity of the luminol-dissolved O 2 system. This proposed Ag NPs@NH 2 –VMSF on the indium tin oxide electrode was applied to construct the ESCL aptasensor for quantitative determination of prostate-specific antigen (PSA), yielding a low detection limit [0.19 pg/mL (S/N = 3)] and a broad linear dynamic range (1 pg/mL to 100 ng/mL). Furthermore, good analytical performance of PSA in serum with satisfactory recoveries and low relative standard deviation values is achieved by our developed ESCL aptasensor, rendering…

In this letter, a sensitive microfluidic immunosensor chip was developed using tetrakis(4-aminophenyl)ethene (TPE)-derived covalent organic frameworks (T-COF) as aggregation-induced electrochemiluminescence (AIECL) emitters and nanobodies as efficient immune recognition units for the detection of thymic stromal lymphopoietin (TSLP), a novel target of asthma. The internal rotation and vibration of TPE molecules were constrained within the framework structure, forcing nonradiative relaxation to convert into pronounced radiative transitions. A camel-derived nanobody exhibited superior specificity, higher residual activity and epitope recognition postcuring compared to monoclonal antibodies. Benefiting from the affinity between silver ions (Ag + ) and cytosine (C), a double-stranded DNA (dsDNA) embedded with Ag + was modified onto the surface of TSLP. A positive correlation was obtained between the TSLP concentration (1.00 pg/mL to 4.00 ng/mL) and ECL intensity, as Ag + was confirmed to be an excellent accelerator of the generation of free radical species. We propose that utilizing COF…

The advancement of acetylcholinesterase (AChE) activity and its inhibitor assays is crucial for clinical diagnosis, drug screening, and environmental monitoring. A nanozyme-mediated cascade reaction system could offer promising prospects for a wide range of applications in such biosensing; however, the creation of nanozyme catalysts with diverse functionalities remains a significant challenge. Herein, we have proposed a multifunctional iron-doped polymer dots (Fe-PDs) nanozyme possessing excellent fluorescence and peroxidase (POD)-mimicking activity. Notably, the Fe-PDs nanozyme is capable of catalyzing H 2 O 2 to produce a series of reactive oxygen species, which can simultaneously quench the fluorescence of Fe-PDs and induce a chromogenic reaction of 3,3′,5,5′-tetramethylbenzidine (TMB), enabling the dual-mode detection of H 2 O 2 through both fluorescence turn-off and absorbance turn-on signals. Furthermore, by integrating acetylcholine (ACh) and choline oxidase (ChOx), we have developed a three-enzyme (AChE–ChOx–POD) cascade-based fluorometric and colorimetric dual-mode sensing…

Small-molecule fluorescent probes have emerged as potential tools for cancer cell imaging-based diagnostic and therapeutic applications, but their limited selectivity and poor imaging contrast hinder their broad applications. To address these problems, we present the design and construction of a novel near-infrared (NIR) biotin-conjugated and viscosity-activatable fluorescent probe, named as QL-VB, for selective recognition and imaging of cancer cells. The designed probe exhibited a NIR emission at 680 nm, with a substantial Stokes shift of 100 nm and remarkably sensitive responses toward viscosity changes in solution. Importantly, QL-VB provided an evidently enhanced signal-to-noise ratio (SNR: 6.2) for the discrimination of cancer cells/normal cells, as compared with the control probe without biotin conjugation (SNR: 1.8). Moreover, we validated the capability of QL-VB for dynamic monitoring of stimulated viscosity changes within cancer cells and employed QL-VB for distinguishing breast cancer tissues from normal tissues in live mice with improved accuracy (SNR: 2.5) in comparison…

Current research endeavors have focused on the combination of various isothermal nucleic acid amplification methods with CRISPR/Cas systems, aiming to establish a more sensitive and reliable molecular diagnostic approach. Nevertheless, most assays adopt a two-step procedure, complicating manual operations and heightening the risk of contamination. Efforts to amalgamate both assays into a single-step procedure have faced challenges due to their inherent incompatibility. Furthermore, the presence of the protospacer adjacent motif (PAM) motif (e.g., TTN or TTTN) in the target double-strand DNA (dsDNA) is an essential prerequisite for the activation of the Cas12-based method. This requirement imposes constraints on crRNA selection. To overcome such limitations, we have developed a novel PAM-free one-step asymmetric recombinase polymerase amplification (RPA) coupled with a CRISPR/Cas12b assay (OAR-CRISPR). This method innovatively merges asymmetric RPA, generating single-stranded DNA (ssDNA) amenable to CRISPR RNA binding without the limitations of the PAM site. Importantly, the…

The detection of physiological phosphates (PPs) is of great importance due to their essential roles in numerous biological processes, but the efficient detection of different PPs simultaneously remains challenging. In this work, we propose a fluorescence sensor array for detecting PPs based on metal-ion-regulated gold nanoclusters (AuNCs) via an indicator-displacement assay. Zn 2+ and Eu 3+ are selected to assemble with two different AuNCs, resulting in quenching or enhancing their fluorescence. Based on the competitive interaction of metal ions with AuNCs and PPs, the fluorescence of AuNCs will be recovered owing to the disassembly of AuNC-metal ion ensembles. Depending on different PPs’ distinct fluorescence responses, a four-channel sensor array was established. The array not only exhibits good discrimination capability for eight kinds of PPs (i.e., ATP, ADP, AMP, GTP, CTP, UTP, PPi, and Pi) via linear discriminant analysis but also enables quantitative detection of single phosphate (e.g., ATP) in the presence of interfering PPs mixtures. Moreover, potential application of the…

In enantiomer recognition and separation, a highly enantioselective approach with universal applicability is urgently desired but hard to realize, especially in the case of chiral molecules. To resolve the trade-off between enantioselectivity and universality, a glutathione (GSH) and methylated cyclodextrins (MCD)-functionalized covalent organic framework (GSH-MCD COF) with porosity and abundant chiral surfaces is presented that was designed and synthesized for recognition and separation of various enantiomers. As expected, the GSH-MCD COF can be used as chiral stationary phases for the separation of various enantiomers, including aromatic alcohols, aromatic acids, amides, amino acids, and organic acids, with performance and versatility even superior to some widely used commercial chiral chromatographic columns. Furthermore, the synthesized GSH-MCD COF shows high enantioselectivity for the rapid recognition and identification of enantiomers and chiral metabolites when coupling to Raman spectroscopy. Molecular simulations suggest that the COF provides a confined microenvironment for…

High Resolution Image Download MS PowerPoint Slide The implementation of quality control strategies is crucial to ensure the reproducibility, accuracy, and meaningfulness of metabolomics data. However, this pivotal step is often overlooked within the metabolomics workflow and frequently relies on the use of nonstandardized and poorly reported protocols. To address current limitations in this respect, we have developed QC omics, a robust, easily implementable and reportable method for monitoring and controlling data quality. The protocol operates in various sequential steps aimed to (i) correct for background noise and carryover, (ii) detect signal drifts and “out-of-control” observations, (iii) deal with missing data, (iv) remove outliers, (v) monitor quality markers to identify samples affected by improper collection, preprocessing, or storage, and (vi) assess overall data quality in terms of precision and accuracy. Notably, this tool considers important issues often neglected along quality control, such as the need of separately handling missing values and truly absent data to…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTCapillary Electrophoresis: A Three-Year Literature ReviewYueyang LiYueyang LiDepartment of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, CanadaMore by Yueyang LiView Biography, Siyu MiaoSiyu MiaoDepartment of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, CanadaMore by Siyu MiaoView Biography, Jiahua TanJiahua TanDepartment of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, CanadaMore by Jiahua TanView Biography, Qi Zhang*Qi ZhangSchool of Pharmacy, Jiangsu University, Zhenjiang, Jiangsu 212013, P. R. China*Email: [email protected]More by Qi ZhangView Biographyhttps://orcid.org/0000-0001-9259-486X, and David Da Yong Chen*David Da Yong ChenDepartment of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada*Email: [email protected]More by David Da Yong ChenView Biographyhttps://orcid.org/0000-0002-3669-6041Cite this: Anal. Chem. 2024, 96, 20, 7799–7816Publication Date (Web):April 10, 2024Publication History…

Laccase, a member of the copper oxidase family, has been used as a green catalyst in the environmental and biochemical industries. However, laccase nanoenzymes are limited to materials with copper as the active site, and noncopper laccase nanoenzymes have been scarcely reported. In this study, inspired by the multiple copper active sites of natural laccase and the redox Cu 2+ /Cu + electron transfer pathway, a novel nitrogen/nickel single-atom nanoenzyme (N/Ni SAE) with high laccase-like activity was prepared by inducing Ni and dopamine precipitation through a controllable water/ethanol interface reaction. Compared with that of laccase, the laccase activity simulated by N/Ni SAE exhibited excellent stability and reusability. The N/Ni SAE exhibited a higher efficiency toward the degradation of 2,4-dichlorophenol, hydroquinone, bisphenol A, and p -aminobenzene. In addition, a sensitive electrochemical biosensor was constructed by leveraging the laccase-like activity of N/Ni SAE; this sensor offered unique advantages in terms of catalytic activity, selectivity, stability, and…

High Resolution Image Download MS PowerPoint Slide Nontargeted screening (NTS) utilizing liquid chromatography electrospray ionization high-resolution mass spectrometry (LC/ESI/HRMS) is increasingly used to identify environmental contaminants. Major differences in the ionization efficiency of compounds in ESI/HRMS result in widely varying responses and complicate quantitative analysis. Despite an increasing number of methods for quantification without authentic standards in NTS, the approaches are evaluated on limited and diverse data sets with varying chemical coverage collected on different instruments, complicating an unbiased comparison. In this interlaboratory comparison, organized by the NORMAN Network, we evaluated the accuracy and performance variability of five quantification approaches across 41 NTS methods from 37 laboratories. Three approaches are based on surrogate standard quantification (parent-transformation product, structurally similar or close eluting) and two on predicted ionization efficiencies (RandFor- IE and MLR- IE ). Shortly, HPLC grade water, tap water,…

Although various oxidase mimetic or peroxidase (POD) mimetic nanozymes have been extensively studied, their poor substrate selectivity significantly inhibits their practical applications. Nanozymes with specific biomolecules as substrates, especially ascorbic acid oxidase (AAO) mimetic nanozymes with ascorbic acid (AA) as a substrate, have scarcely been studied. Herein, inspired by the multi-Cu atom sites and the redox electron transfer pathway of Cu 2+ /Cu + in the natural AAO, atomically dispersed Cu sites immobilized on N-doped porous carbon (Cu-N/C) are artificially designed to simulate the function of natural AAO. Compared with their natural counterparts, the Cu-N/C catalysts exhibited higher catalytic efficiency and superior stability. Combined theoretical calculation and experimental characterizations reveal that the Cu-N/C nanozymes could catalyze the AA oxidation through a 2e – oxygen reduction pathway with H 2 O 2 as the product. Moreover, the Cu-N/C nanozymes also possess high POD activity. As a proof-of-concept application, Cu-N/C can simultaneously realize AA detection…

Ferroptosis is an iron-dependent programmed cell death that is characterized by the dysregulation of lipid reactive oxygen species (ROS) production, causing abnormal changes in hypochlorous acid (HClO) levels in lysosomes. Super-resolution imaging can observe the fine structure of the lysosome at the nanometer level; therefore, it can be used to detect lysosome HClO levels during ferroptosis at the suborganelle level. Herein, we utilize a ratiometric fluorescent probe, SRF-HClO, for super-resolution imaging of lysosome HClO. Structured-illumination microscopy (SIM) improves the accuracy of lysosome targeting and enables the probe SRF-HClO to be successfully applied to rapidly monitor the up-regulated lysosome HClO at the nanoscale during inflammation and ferroptosis. Importantly, the probe SRF-HClO can also detect HClO changes in inflammatory and ferroptosis mice and evaluate the inhibitory effect of ferroptosis on mice tumors.

At some levels, single-entity electrochemistry (SEE) is enigmatic. First defined at a Royal Society of Chemistry Faraday Discussion in 2016, (1−5) SEE encompasses a broad range of studies that are linked by underlying concepts, principles, and experimental/theoretical challenges that can include low current, high speed, and statistical treatments of electrochemical signals that originate from a single “thing”, that “thing” being a single nanoparticle, protein, or cell, etc. Since the inception of the general concept, the field has expanded and grown to studies beyond the original descriptions, often as technology and methods applicable to SEE have grown. (6−10) SEE has proven to be especially timely, as methods are often well-matched to advances in data-driven approaches like machine learning (ML) and artificial intelligence. In this Review, we highlight selected examples from the SEE community with an emphasis on results in the last two years. Examples are classified based on technique or approach and include purely electrochemical examples, as well as opto-electrochemical…

The urgent need for sensitive and accurate assays to monitor acetylcholinesterase (AChE) activity and organophosphorus pesticides (OPs) arises from the imperative to safeguard human health and protect the ecosystem. Due to its cost-effectiveness, ease of operation, and rapid response, nanozyme-based colorimetry has been widely utilized in the determination of AChE activity and OPs. However, the rational design of nanozymes with high activity and specificity remains a great challenge. Herein, trace amount of Bi-doped core–shell Pd@Pt mesoporous nanospheres (Pd@PtBi 2 ) have been successfully synthesized, exhibiting good peroxidase-like activity and specificity. With the incorporation of trace bismuth, there is a more than 4-fold enhancement in the peroxidase-like performance of Pd@PtBi 2 compared to that of Pd@Pt. Besides, no significant improvement of oxidase-like and catalase-like activities of Pd@PtBi 2 was found, which prevents interference from O 2 and undesirable consumption of substrate H 2 O 2 . Based on the blocking impact of thiocholine, a colorimetric detection platform…

Accurate and rapid differentiation and authentication of agricultural products based on their origin and quality are crucial to ensuring food safety and quality control. However, similar chemical compositions and complex matrices often hinder precise identification, particularly for adulterated samples. Herein, we propose a novel method combining multiplex surface-enhanced Raman scattering (SERS) fingerprinting with a one-dimensional convolutional neural network (1D-CNN), which enables the effective differentiation of the category, origin, and grade of agricultural products. This strategy leverages three different SERS-active nanoparticles as multiplex sensors, each tailored to selectively amplify the signals of preferentially adsorbed chemicals within the sample. By strategically combining SERS spectra from different NPs, a 'SERS super-fingerprint' is constructed, offering a more comprehensive representation of the characteristic information on agricultural products. Subsequently, utilizing a custom-designed 1D-CNN model for feature extraction from the 'super-fingerprint'…

Hydrogen has been widely used in industrial and commercial applications as a carbon-free, efficient energy source. Due to the high flammability and explosion risk of hydrogen-air mixtures, it is vital to develop sensors featuring fast-responding and high sensitivity for hydrogen leakage detection. This paper presents a miniaturized electrochemical gas sensor by elaborately establishing a nanocomposite and thin ionic liquid interface for highly sensitive and rapid electrochemical detection of hydrogen, in which a remarkable response time and recovery time of approximately 6 s was achieved at room temperature. A screen-printed carbon electrode was modified with a reduced graphene oxide-carbon nanotube (rGO-CNT) hybrid and platinum-palladium (Pt-Pd) bimetallic nanoparticles to realize high sensitivity. To achieve miniaturization and high stability of the sensor, a thin-film room-temperature ionic liquid (RTIL) was employed as the electrolyte with a significantly decreased response time. The fast-responding hydrogen sensor demonstrates excellent performance with high sensitivity,…

In recent years, the CRISPR/Cas12a-based sensing strategy has shown significant potential for specific target detection due to its rapid and sensitive characteristics. However, the “always active” biosensors are often insufficient to manipulate nucleic acid sensing with high spatiotemporal control. It remains crucial to develop nucleic acid sensing devices that can be activated at the desired time and space by a remotely applied stimulus. Here, we integrated photoactivation with the CRISPR/Cas12a system for DNA and RNA detection, aiming to provide high spatiotemporal control for nucleic acid sensing. By rationally designing the target recognition sequence, this photoactivation CRISPR/Cas12a system could recognize HPV16 and survivin, respectively. We combined the lateral flow assay strip test with the CRISPR/Cas12a system to realize the visualization of nucleic acid cleavage signals, displaying potential instant test application capabilities. Additionally, we also successfully realized the temporary control of its fluorescent sensing activity for survivin by photoactivation in vivo,…

Nanopore sensing technology, as an emerging analytical method, has the advantages of simple operation, fast output, and label-free and has been widely used in fields such as protein analysis, gene sequencing, and biomarker detection. Inspired by biological ion channels, scientists have prepared various artificial solid-state nanopores/nanochannels. Biological ion channels have extremely high ion transport selectivity, while solid-state nanopores/nanochannels have poor selectivity. The selectivity of solid-state nanopores and nanochannels can be enhanced by modifying channel charge, varying pore size, incorporating specific chemical functionality, and adjusting operating (or solution) conditions. This Perspective highlights pore-in modification strategies for enhancing the selectivity of solid-state nanopore/nanochannel sensors by summarizing the articles published in the last 10 years. The future development prospects and challenges of pore-in modification in solid-state nanopore and nanochannel sensors are discussed. This Perspective helps readers better understand nanopore sensing…

The detection of endogenous phenolic compounds (EPs) in food is of great significance in elucidating their bioactivity and health effects. Here, a novel bifunctional vanillic acid-Cu (VA-Cu) nanozyme with peroxidase-like and laccase-like activities was successfully prepared. The peroxidase mimic behavior of VA-Cu nanozyme can catalyze 3,3',5,5'-tetramethylbenzidine (TMB) to generate oxidized TMB (oxTMB). Owing to the high reducing power of EPs, this process can be inhibited, and the degree of inhibition increases with the increase of reaction time. Additionally, owing to the outstanding laccase mimic behavior of the VA-Cu, it can facilitate the oxidation of various EPs, resulting in the formation of colored quinone imines, and the degree of catalysis increases with the increase of reaction time. Based on the interesting experimental phenomena mentioned above, a six-channel nanozyme sensor array (2 enzyme-mimic activities × 3 time points = 6 sensing channels) was constructed, successfully achieving discriminant analysis of nine EPs. In addition, the combination of artificial neural…

The effective applications of electrochemiluminescence (ECL) across various fields necessitate ongoing research into novel luminophores and ECL strategies. In this study, self-luminous flower-like nanocomposites (Eu-tcbpe-MOF) were prepared by coordination self-assembly using the aggregation-induced emission material 1,1,2,2-tetrakis(4-carboxyphenyl)ethylene (H 4 TCBPE) and Eu(III) ions as the precursors. Compared with the monomers and aggregates of H 4 TCBPE, Eu-tcbpe-MOF exhibits stronger ECL emission. Such enhanced electrochemiluminescence is due to coordination as the coordination-triggered electrochemiluminescence (CT-ECL) enhancement effect. In this study, a cubic-structured nanocomposite (Co 9 S 8 @Au@MoS 2 ) was used as an efficient quencher, and a more sensitive ECL detection platform was achieved by two quenching mechanisms: resonance energy transfer and competitive consumption of coreactants. N, N -Diethylethanolamine (DBAE) was used as a coreactant, and DBAE has a faster electron transfer rate and stronger energy supply efficiency than the traditional anodoluminescent…

New strategies for the simultaneous and portable detection of multiple enzyme activities are highly desirable for clinical diagnosis and home care. However, the methods developed thus far generally suffer from high costs, cumbersome procedures, and heavy reliance on large-scale instruments. To satisfy the actual requirements of rapid, accurate, and on-site detection of multiple enzyme activities, we report herein a smartphone-assisted programmable microfluidic paper-based analytical device (μPAD) that utilizes colorimetric and photothermal signals for simultaneous, accurate, and visual quantitative detection of alkaline phosphatase (ALP) and butyrylcholinesterase (BChE). Specifically, the operation of this μPAD sensing platform is based on two sequential steps. Cobalt-doped mesoporous cerium oxide (Co-m-CeO 2 ) with remarkable peroxidase-like activities under neutral conditions first catalytically decomposes H 2 O 2 for effectively converting colorless 3,3′,5,5′-tetramethylbenzidine (TMB) into blue oxidized TMB (oxTMB). The subsequent addition of ALP or BChE to their respective…

A spatial-potential-color-resolved bipolar electrode electrochemiluminescence biosensor (BPE-ECL) using a CuMoOx electrocatalyst was constructed for the simultaneous detection and imaging of tetracycline (TET) and lincomycin (LIN). HOF-101 emitted peacock blue light under positive potential scanning, and CdSe quantum dots (QDs) emitted green light under negative potential scanning. CuMoOx could catalyze the electrochemical reduction of H 2 O 2 to greatly increase the Faradic current of BPE and realize the ECL signal amplification. In channel 1, CuMoOx-Aptamer II (TET) probes were introduced into the BPE hole (left groove A) by the dual aptamer sandwich method of TET. During positive potential scanning, the polarity of BPE (left groove A) was negative, resulting in the electrochemical reduction of H 2 O 2 catalyzed by CuMoOx, and the ECL signal of HOF-101 was enhanced for detecting TET. In channel 2, CuMoOx-Aptamer (LIN) probes were adsorbed on the MXene of the driving electrode (DVE) hole (left groove B) by hydrogen-bonding and metal-chelating interactions. LIN bound with its…

Development of reliable methods for the detection of potential biomarkers is of the utmost importance for an early diagnosis of critical diseases and disorders. In this study, a novel lanthanide-functionalized carbon dot-based fluorescent probe Zn-CD@Eu is reported for the ratiometric detection of dipicolinic acid (DPA) and uric acid (UA). The Zn-CD@Eu nanoprobe was obtained from a simple room-temperature reaction of zinc-doped carbon dots (Zn-CD) and the EDTA–Eu lanthanide complex. Under optimal conditions, a good linear response was obtained for DPA in two concentration ranges of 0−55 and 55−100 μM with a limit of detection of 0.53 and 2.2 μM respectively, which is significantly below the infectious dosage of anthrax (∼55 μM). Furthermore, the Zn-CD@Eu/DPA system was employed for the detection of UA with a detection limit of 0.36 μM in the linear range of 0–100 μM. The fluorescent probe was successfully implemented for determining DPA and UA in human blood serum, sweat, and natural water bodies with considerable recovery rates. In addition, the potential of the nanoprobe for ex…

There is growing attention focused toward the problems of ecological sustainability and food safety raised from the abuse of herbicides, which underscores the need for the development of a portable and reliable sensor for simple, rapid, and user-friendly on-site analysis of herbicide residues. Herein, a novel multifunctional hydrogel composite is explored to serve as a portable and flexible sensor for the facile and efficient analysis of atrazine (ATZ) residues. The hydrogel electrode is fabricated by doping graphite-phase carbon nitride (g-C 3 N 4 ) into the aramid nanofiber reinforced poly(vinyl alcohol) hydrogel via a simple solution-casting procedure. Benefiting from the excellent electroactivity and large specific surface area of the solid nanoscale component, the prepared hydrogel sensor is capable of simple, rapid, and sensitive detection of ATZ with a detection limit down to 0.002 ng/mL and per test time less than 1 min. After combination with a smartphone-controlled portable electrochemical analyzer, the flexible sensor exhibited satisfactory analytical performance for the…

A rapid photoacoustic (PA) exhaust gas analyzer is presented for simultaneous measurements of nitrogen dioxide (NO 2 ) and sulfur dioxide (SO 2 ). A laser diode (LD) emitting at 450 nm and a light-emitting diode (LED) with a peak wavelength of 275 nm operated simultaneously, producing PA signals of NO 2 and SO 2, respectively. The LD and LED were modulated at different frequencies of 2568 and 2570 Hz, and their emission light beams were transmitted through two resonant tubes in a differential PA cell (DPAC), respectively. A self-made dual-channel digital lock-in amplifier was used to realize the simultaneous detection of dual-frequency PA signals. Cross interference between the PA signals at the two different frequencies was reduced to 0.02% by using a lock-in amplifier. In order to achieve a rapid dynamic measurement, gas sampling was accelerated by an air pump. The use of mufflers and the differential PA detection technique significantly reduced the gas sampling noise. When the gas flow rate was 1000 sccm, the response time of the PA dual-gas analyzer was 8 and 17 s for NO 2 and…

To achieve high sensitivity detection of dual-component greenhouse gases carbon dioxide and methane simultaneously, a multimechanism synergistic enhanced all-optical photoacoustic spectroscopy gas analyzer is presented. The acoustic resonance of the photoacoustic cell and the mechanical resonance of a fiber-optic cantilever acoustic sensor are used to enhance the photoacoustic signals of the dual-component gas. The optimized multipass beam reflection structure enhances the effective excitation power of the dual-component gas. The highly sensitive detection of carbon dioxide and methane at dual-frequency operating points is realized by dual-channel laser modulation combined with dual-input digital lock-in amplification technology. The Allan–Werle deviation analysis results show that with a 100 s average time, the minimum detection limits of carbon dioxide and methane are 76.5 and 1.9 ppb, respectively. The corresponding normalized noise equivalent absorption (NNEA) coefficients are 3.1 × 10 –10 and 2.9 × 10 –10 cm –1 W/Hz 1/2, respectively.

In traditional luminol electrochemiluminescence (ECL) systems, hydrogen peroxide (H 2 O 2 ) and dissolved oxygen (DO) are the commonly used coreactants to generate reactive oxygen species (ROS) for ECL emission. However, the self-decomposition of hydrogen peroxide and the limited solubility and content of oxygen in solution undoubtedly restrict the luminescence efficiency and stability of the luminol ECL system. Inspired by the ROS-mediated ECL mechanism, we pioneered hydroxide ion as an advanced luminol ECL coreactant using nickel-doped and carbon nanotube-modified tungsten oxide (Ni-WO x -CNT) as the coreactant accelerator. Owing to the excellent catalytic activity of Ni-WO x -CNT, amounts of ROS were generated from OH – at a low excitation voltage, which subsequently reacted with luminol anion radicals and triggered intense ECL signals. Experiments confirmed an impressive ECL behavior in terms of high luminescent intensity (85,563 a.u.) and super stability over 1300 consecutive tests; both are superior to those recently reported luminol-H 2 O 2 and luminol-DO systems with smaller…

Acute alcoholic liver injury (AALI) has become an important cause of liver disease worldwide, and there is an urgent need to develop noninvasive and sensitive methods to detect and evaluate AALI. We report herein three novel but readily available mitochondrial targeting fluorescence probes ( ICR, ICJ, and ICQ ) for AALI detection. These probes contain different electron-donating groups, among which ICQ exhibits NIR fluorescence (740 nm), a large Stokes shift (110 nm), and a sensitive response to viscosity (73-fold enhancement in fluorescence from water to glycerol), making it suitable for in vivo imaging. ICQ also exhibits an excellent ability to image mitochondrial viscosity changes in cells. More importantly, ICQ can target the liver selectively and image the viscosity changes in the liver noninvasively. Through establishing an AALI mouse model, ICQ was successfully applied to the in situ imaging changes in liver viscosity during the AALI process. The results showed a significant increase in liver viscosity in AALI mice, indicating that viscosity can serve as a marker for AALI,…

Spectrum–structure correlation is playing an increasingly crucial role in spectral analysis and has undergone significant development in recent decades. With the advancement of spectrometers, the high-throughput detection triggers the explosive growth of spectral data, and the research extension from small molecules to biomolecules accompanies massive chemical space. Facing the evolving landscape of spectrum–structure correlation, conventional chemometrics becomes ill-equipped, and deep learning assisted chemometrics rapidly emerges as a flourishing approach with superior ability of extracting latent features and making precise predictions. In this review, the molecular and spectral representations and fundamental knowledge of deep learning are first introduced. We then summarize the development of how deep learning assist to establish the correlation between spectrum and molecular structure in the recent 5 years, by empowering spectral prediction (i.e., forward structure–spectrum correlation) and further enabling library matching and de novo molecular generation (i.e., inverse…

Abnormal lipid droplets (LDs) are known to be intimately bound with the occurrence and development of cancer, allowing LDs to be critical biomarkers for cancers. Aggregation-induced emission luminogens (AIEgens), with efficient reactive oxygen species (ROS) production performance, are prime photosensitizers (PSs) for photodynamic therapy (PDT) with imaging. Therefore, the development of dual-functional fluorescent probes with aggregation-induced emission (AIE) characteristics that enable both simultaneous LD monitoring and imaging-guided PDT is essential for concurrent cancer diagnosis and treatment. Herein, we reported the development of a novel LD-targeting fluorescent probe (TDTI) with AIE performance, which was expected to realize the integration of cancer diagnosis through LD visualization and cancer treatment via PDT. We demonstrated that TDTI, with typical AIE characteristics and excellent photostability, could target LDs with high specificity, which enables the dynamic tracking of LDs in living cells, specific imaging of LDs in zebrafish, and the differentiation of cancer…

Microplastics are increasingly reported, not only in the environment but also in a wide range of food commodities. While studies on microplastics in food abound, the current state of science is limited in its application to regulatory risk assessment by a continued lack of standardized definitions, reference materials, sample collection and preparation procedures, fit-for purpose analytical methods for real-world and environmentally relevant plastic mixtures, and appropriate quality controls. This is particularly the case for nanoplastics. These methodological challenges hinder robust, quantitative exposure assessments of microplastic and nanoplastic mixtures from food consumption. Furthermore, limited toxicological studies on whether microplastics and nanoplastics adversely impact human health are also impeded by methodology challenges. Food safety regulatory agencies must consider both the exposure and the risk of contaminants of emerging concern to ascertain potential harm. Foundational to this effort is access to and application of analytical methods with the capability to…

Breast cancer remains the most frequently diagnosed cancer globally, and the metastasis of this malignancy is the primary cause of mortality in breast cancer patients. Hence, prompt diagnosis and timely detection of metastatic breast cancer are critical for effective therapeutic intervention. Both progression and metastasis of this malignancy are closely associated with aberrant expression of specific microRNAs (miRNAs) and enzymes. To facilitate breast cancer diagnosis and concomitant identification of metastatic breast cancer, we have engineered an innovative electrochemiluminescence (ECL)-based sensing platform integrated with enzyme-free DNA amplification circuits for dual functionality. Specifically, microRNA-21 (miR-21) is employed as a biomarker for breast cancer, and miR-21 induces the quenching of the ECL signal from luminophores via a strategically designed catalytic three-hairpin assembly (CTHA) circuit. Subsequently, miR-105 levels are measured via toehold-mediated strand displacement reactions (TSDR). Here, miR-105 restores the initially quenched ECL signal, enabling…

Fluorescence array technologies have attracted great interest in the sensing field because of their high sensitivity, low cost, and capability of multitarget detection. However, traditional array sensing relies on multiple independent sensors and thus often requires time-consuming and laborious measurement processes. Herein, we introduce a novel fluorescence array strategy of the array-on-a-metal–organic framework (MOF), which integrates multiple array elements into a single MOF matrix to achieve facile sensing and discrimination of multiple target analytes. As a proof-of-concept system, we constructed a luminescent MOF containing three different emitting channels, including a lanthanide ion (europium/Eu 3+, red emission), a fluorescent dye (7-hydroxycoumarin-4-acetic acid/HCAA, blue emission), and the MOF itself (UiO-66-type MOF, blue-violet emission). Five structurally similar nitroaromatic compounds (NACs) were chosen as the targets. All three channels of the array-on-a-MOF displayed rapid and stable fluorescence quenching responses to NACs (response equilibrium achieved within…

Perfluorooctanesulfonic acid potassium salt (PFOS) residues in ecosystems over long periods are of increasing concern and require a selective and stable optical probe for monitoring. Herein, two functional groups (-F and -NH 2 ) with opposite electronic modulation ability were introduced into Fe/Zn-BDC (denoted as Fe/Zn-BDC-F 4 and Fe/Zn-BDC-NH 2, respectively) to tailor the coordination environment of the Fe metal center, further regulating the nanozyme activity efficiently. Notably, the peroxidase-like activity is related to the coordination environment of the nanozymes and obeys the following order Fe/Zn-BDC-F 4 > Fe/Zn-BDC > Fe/Zn-BDC-NH 2 . Based on the excellent peroxidase-like activity of Fe/Zn-BDC-F 4 and the characteristics of being rich in F atoms, a rapid, selective, and visible colorimetric method was developed for detecting PFOS with a detection limit of 100 nM. The detection mechanism was attributed to various interaction forces between Fe/Zn-BDC-F 4 and PFOS, including electrostatic interactions, Fe–S interactions, Fe–F bonds, and halogen bonds. This work not only…

The self-powered electrochemical sensor (SPES), an analytical sensing device without external power supply, is integrated with the dual function of power supply and detection performance, which lay the foundation for the development of intelligent and portable electrochemical sensing devices. Herein, a novel SPES based on a zinc-air battery was constructed for the detection of hydrogen sulfide (H 2 S) in the lysate of colon cancer cells. Typically, an Fe/Fe 3 C@graphene foam with oxygen reduction performance was used to construct SPES based on a zinc-air battery (ZAB-SPES), which brings the open-circuit voltage to 1.30 V. Among them, the poisoning effect of H 2 S causes the catalytic performance of the oxygen reduction catalyst to decrease, causing a significant decrease in the discharge voltage of ZAB. Based on this principle, ZAB-SPES was constructed for the detection of H 2 S using a digital multimeter. The proposed ZAB-SPES demonstrated good selectivity and reproducibility for detecting H 2 S compared to the results of the H 2 S-specific fluorescence probe. This strategy…

Ketogenic diets have attracted substantial interest in the treatment of chronic diseases, but there are health risks with long-term regimes. Despite the advancements in diagnostic and therapeutic methods in modern medicine, there is a huge gap in personalized health management of this dietary strategy. Hence, we present a wearable microneedle biosensor for real-time ketone and glucose monitoring. The microneedle array possesses excellent mechanical properties, allowing for consistent sampling of interstitial biomarkers while reducing the pain associated with skin puncture. Vertical graphene with outstanding electrical conductivity provides the resulting sensor with a high sensitivity of 234.18 μA mM –1 cm –2 and a low limit detection of 1.21 μM. When this fully integrated biosensor was used in human volunteers, it displayed an attractive analytical capability for tracking the dynamic metabolite levels. Moreover, the results of the on-body evaluation established a significant correlation with commercial blood measurements. Overall, this cost-effective and efficient sensing platform…

Accurate measurement of cancer markers in urine is a convenient method for tumor monitoring. However, the concentration of cancer markers in urine is so low that it is difficult to achieve their measurement. Photoelectrochemical (PEC) sensors are a promising technology to realize the detection of trace cancer markers due to their high sensitivity. Currently, the interference of nonspecific biomolecules in urine is the main reason affecting the high sensitivity and selectivity of PEC sensors in detecting cancer markers. In this work, a strategy of oxygen vacancy (OV) modulation is proposed to construct a fouling-resistant PEC aptamer sensing platform for the detection of α-fetoprotein (AFP), a liver cancer marker. The introduction of OVs induces the formation of intermediate localized states in the photoelectric material, which not only facilitates the separation of photogenerated carriers but also leads to the redshift of the light absorption edge. More importantly, OVs with positive electrical properties can be employed to modify the antifouling layer (C-PEG) with negatively…

Novel hollow AuAg nanoboxes (AuAg NBs) were designed for an innovative electrochemiluminescence (ECL) sensor to ultrasensitively detect Pb 2+ and Hg 2+ with the aid of DNAzyme and “thymine–Hg 2+ –thymine” (“T–Hg 2+ –T”) structure. AuAg NBs are employed as an excellent surface plasma resonance (SPR) source, as well as an effective coreaction accelerator for the CoNi NFs/S 2 O 8 2– system to greatly improve ECL performance. To detect Pb 2+, the DNAzyme catalyzes the cleavage of ribonucleic acid targets into numerous small nucleic acid fragments, leading to an ECL signal. When Hg 2+ is added, the thymine–thymine (T–T) mismatches of the Hg 2+ aptamer bind Hg 2+ to form the “T–Hg 2+ –T” structure, which not only inhibits the SPR process but also produces a large steric hindrance, thus quenching the ECL signal and allowing quantification of Hg 2+ . The novel ECL sensor quantifies Pb 2+ in the range of 0.1 fM to 0.1 μM with a limit of detection of 0.07 fM and Hg 2+ in the range of 10 pM to 1 μM with a LOD of 4.07 pM.

Paper-based lateral flow immunoassays (LFIAs) are cost-effective, portable, and simple methods for detection of diverse analytes, which however only provide qualitative or semiquantitative results and lack sufficient sensitivity. A combination of LFIA and electrochemical detection, namely, electrochemical lateral flow immunoassay (eLFIA), enables quantitative detection of analytes with high sensitivity, but the integration of external electrodes makes the system relatively expensive and unstable. Herein, the working, counter, and reference electrodes were prepared directly on the nitrocellulose membrane using screen printing, which remarkably simplified the structure of eLFIA and decreased the cost. Moreover, a horseradish peroxidase (HRP)-based electrochemical signal amplification strategy was used for further increasing the analytical sensitivity. HRP captured on the working electrode can catalyze the oxidation of tetramethylbenzidine (TMB) to form the TMB-TMB ox precipitate on the electrode surface, which as an electrochemically active product can output an amplified current for…

Prostate-specific antigen (PSA) is a key marker for a prostate cancer diagnosis. The low sensitivity of traditional lateral flow immunoassay (LFIA) methods makes them unsuitable for point-of-care testing. Herein, we designed a nanozyme by in situ growth of Prussian blue (PB) within the pores of dendritic mesoporous silica (DMSN). The PB was forcibly dispersed into the pores of DMSN, leading to an increase in exposed active sites. Consequently, the atom utilization is enhanced, resulting in superior peroxidase (POD)-like activity compared to that of cubic PB. Antibody-modified DMSN@PB nanozymes serve as immunological probes in an enzymatic-enhanced colorimetric and photothermal dual-signal LFIA for PSA detection. After systematic optimization, the LFIA based on DMSN@PB successfully achieves a 4-fold amplification of the colorimetric signal within 7 min through catalytic oxidation of the chromogenic substrate by POD-like activity. Moreover, DMSN@PB exhibits an excellent photothermal conversion ability under 808 nm laser irradiation. Accordingly, photothermal signals are introduced to…

In light of the growing awareness regarding the ubiquitous presence of microplastics (MPs) in our environment, recent efforts have been made to integrate Artificial Intelligence (AI) technology into MP detection. Among spectroscopic techniques, Raman spectroscopy is preferred for the detection of MP particles measuring less than 10 μm, as it overcomes the diffraction limitations encountered in Fourier transform infrared (FTIR). However, Raman spectroscopy's inherent limitation is its low scattering cross section, which often results in prolonged data collection times during practical sample measurements. In this study, we implemented a convolutional neural network (CNN) model alongside a tailored data interpolation strategy to expedite data collection for MP particles within the 1-10 μm range. Remarkably, we achieved the classification of plastic types for individual particles with a mere 0.4 s of exposure time, reaching an approximate confidence level of 85.47(±5.00)%. We postulate that the result significantly accelerates the aggregation of microplastic distribution data in…

Covalent organic frameworks (COFs) are attractive adsorbents for sample pretreatment due to their unique structure and properties. However, the selectivity of COFs for the extraction of hazardous compounds is still limited due to the lack of specific interactions between COFs and targets. Herein, we report a pore size adjustment strategy for room-temperature synthesis of molecularly imprinted COF (MICOF) for selective extraction of zearalenone (ZEN) in complex food samples. The three-dimensional building block tetra(4-aminophenyl) methane was used as a functional monomer, while dialdehyde monomers with different numbers of benzene ring were used to adjust the pore size of MICOF to match with the size of ZEN molecules. The prepared MICOF gave the largest adsorption capacity of 177.2 mg g –1 and the highest imprinting factor of 10.1 for ZEN so far. MICOF was used as the adsorbent for dispersed solid-phase extraction in combination with high-performance liquid chromatography for the determination of trace ZEN in cereals. The high selectivity of the developed method allows simple…

Cerebral ischemia–reperfusion injury (CIRI), a cause of cerebral dysfunction during cerebral infarction treatment, is closely associated with mitochondrial viscosity and hydrogen peroxide (H 2 O 2 ). However, the accurate measurement of mitochondrial viscosity and H 2 O 2 levels in CIRI is challenging because of the lack of sufficient selectivity and blood–brain barrier (BBB) penetration of existing monitoring tools related to CIRI, hampering the exploration of the role of mitochondrial viscosity and H 2 O 2 in CIRI. To address this issue, we designed an activatable fluorescent probe, mitochondria-targeting styryl-quinolin-ium ( Mito-IQS ), with excellent properties including high selectivity, mitochondrial targeting, and BBB penetration, for the visualization of mitochondrial viscosity and H 2 O 2 in the brain. Based on the real-time monitoring capabilities of the probe, bursts of mitochondrial viscosity and H 2 O 2 levels were visualized during CIRI. This probe can be used to monitor the therapeutic effects of butylphthalein treatment. More importantly, in vivo experiments further…

High Resolution Image Download MS PowerPoint Slide Sepsis is an extremely dangerous medical condition that emanates from the body’s response to a pre-existing infection. Early detection of sepsis-inducing bacterial infections can greatly enhance the treatment process and potentially prevent the onset of sepsis. However, current point-of-care (POC) sensors are often complex and costly or lack the ideal sensitivity for effective bacterial detection. Therefore, it is crucial to develop rapid and sensitive biosensors for the on-site detection of sepsis-inducing bacteria. Herein, we developed a graphene oxide CRISPR-Cas12a (GO-CRISPR) biosensor for the detection of sepsis-inducing bacteria in human serum. In this strategy, single-stranded (ssDNA) FAM probes were quenched with single-layer graphene oxide (GO). Target-activated Cas12a trans -cleavage was utilized for the degradation of the ssDNA probes, detaching the short ssDNA probes from GO and recovering the fluorescent signals. Under optimal conditions, we employed our GO-CRISPR system for the detection of Salmonella Typhimurium ( S .…

The molecular detection of multiple respiratory viruses provides evidence for the rational use of drugs and effective health management. Herein, we developed and tested the clinical performance of an electrohydrodynamic-driven nanobox-on-mirror platform (E-NoM) for the parallel, accurate, and sensitive detection of four respiratory viral antigens. The E-NoM platform uses gold-silver alloy nanoboxes as the core material with the deposition of a silver layer as a shell on the core surfaces to amplify and enable a reproducible Raman signal readout that facilitates accurate detection. Additionally, the E-NoM platform employs gold microelectrode arrays as the mirror with electrohydrodynamics to manipulate the fluid flow and enhance molecular interactions for an improved biosensing response. The presence of viral antigens binds the nanobox-based core-shell nanostructure on the gold microelectrode and creates the nanocavity with extremely strong "hot spots" to benefit sensitive analysis. Significantly, in a large clinical cohort with 227 patients, the designed E-NoM platform demonstrates…

The accurate quantification of cancer-derived exosomes, which are emerging as promising noninvasive biomarkers for liquid biopsies in the early diagnosis of cancer, is becoming increasingly imperative. In our work, we developed a magnetically controlled photothermal, colorimetric, and fluorescence trimode aptasensor for human gastric cancer cell (SGC-7901)-derived exosomes. This sensor relied on CP/Mn-PBA DSNBs nanocomposites, created by decorating copper peroxide (CP) nanodots on polyethyleneimine-modified manganese-containing Prussian blue analogues double-shelled nanoboxes (PEI-Mn-PBA DSNBs). Through self-assembly, we attached CD63 aptamer-labeled CP/Mn-PBA DSNBs (Apt-CP/Mn-PBA DSNBs) to complementary DNA-labeled magnetic beads (cDNA-MB). During exosome incubation, these aptamers preferentially formed complexes with exosomes, and we efficiently removed the released CP/Mn-PBA DSNBs by using magnetic separation. The CP/Mn-PBA DSNBs exhibited high photoreactivity and photothermal conversion efficiency under near-infrared (NIR) light, leading to temperature variations under 808 nm…

The accurate prediction of tandem mass spectra from molecular structures has the potential to unlock new metabolomic discoveries by augmenting the community's libraries of experimental reference standards. Cheminformatic spectrum prediction strategies use a "bond-breaking" framework to iteratively simulate mass spectrum fragmentations, but these methods are (a) slow due to the need to exhaustively and combinatorially break molecules and (b) inaccurate as they often rely upon heuristics to predict the intensity of each resulting fragment; neural network alternatives mitigate computational cost but are black-box and not inherently more accurate. We introduce a physically grounded neural approach that learns to predict each breakage event and score the most relevant subset of molecular fragments quickly and accurately. We evaluate our model by predicting spectra from both public and private standard libraries, demonstrating that our hybrid approach offers state-of-the-art prediction accuracy, improved metabolite identification from a database of candidates, and higher interpretability…

In this work, we present a simple and novel digital surface-enhanced Raman spectroscopy (SERS)-microfluidic chip designed for the rapid and accurate quantitative detection of microorganisms. The chip employs a high-density inverted pyramid microcavity (IPM) array to separate and isolate microbial samples. The presence or absence of target microorganisms is determined by scanning the IPM array using SERS and identifying the characteristic Raman bands. This approach allows for the “digitization” of the SERS response of each IPM, enabling quantification through the application of mathematical statistical techniques. Significantly, precise quantitative detection of yeast was achieved within a concentration range of 10 6 –10 9 cells/mL, with the maximum relative standard deviation from the concentration calibrated by the cultivation method being 5.6%. This innovative approach efficiently addresses the issue of irregularities in SERS quantitative detection, which arises due to fluctuations in SERS intensity and poor reproducibility. We strongly believe that this digital SERS-microfluidic…

3D printing has changed many industries and research areas, and it is poised to do the same for electrochemistry and electroanalytical sciences. The ability to easily shape electrically conductive parts in complex geometries, something very difficult to do using traditional manufacturing techniques, can now be easily accomplished at home, opening the possibility of fabricating electrodes and electrochemical cells with geometries that were once unimaginable. This ability can be a milestone in electrochemistry, allowing the fabrication of systems tailored to specific applications. Unfortunately, this is not what is seen to date, with 3D printing mostly reproducing "traditional" designs, using little of the "freedom of design" promised by the technology. We reason that these results come from too much focus on reproducing the electrochemical behavior of metallic electrodes instead of understanding how material properties impact the performance of 3D printed electrodes and working within these constraints. 3D printing will change electrochemistry and electroanalytical sciences if we…

Timely screening for harmful pathogens is a great challenge in emergencies where traditional culture methods suffer from long assay time and alternative methods are limited by poor accuracy and low robustness. Herein, we present a dCas9-mediated colorimetric and surface-enhanced Raman scattering (SERS) dual-signal platform (dCas9-CSD) to address this challenge. Strategically, the platform used dCas9 to accurately recognize the repetitive sequences in amplicons produced by loop-mediated isothermal amplification (LAMP), forming nucleic acid frameworks that assemble numerous bifunctional gold–platinum (Au@Pt) nanozymes into chains on the surface of streptavidin-magnetic beads (SA-MB). The collected Au@Pt converted colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidized TMB (oxTMB) via its Pt shell and then enhanced the Raman signal of oxTMB by its Au core. Therefore, the presence of Salmonella could be dexterously converted into cross-validated colorimetric and SERS signals, providing more reliable conclusions. Notably, dCas9-mediated secondary recognition of amplicons reduced…

While designing anisotropic noble metal nanoparticles (NPs) can enhance the signal intensity of Raman dyes, more sensitive surface-enhanced Raman scattering (SERS) probes can be designed by oriented self-assembly of noble metal nanomaterials into dimers or higher-order nanoclusters. In this study, we engineered a self-assembly strategy in living cells for real-time fluorescence and SERS dual-channel detection of intracellular microRNAs (miRNAs), using Mg 2+ -dependent 8–17E DNAzyme sequences as the driving motors, gold nanocubes (AuNCs) as the driver components, and three-branched double-stranded DNA as the linking tool. The assembly selects adenine in DNA as a reporter molecule, simplifying the labeling process of Raman reporter molecules and reducing the synthesis process. In addition, adenine is stably distributed between the faces of AuNCs and the wide hotspot region gives good reproducibility of the adenine SERS signal. In this strategy, the SERS channel was consistently stable and more sensitive compared to the fluorescence channel. Among them, the detection limit of the SERS…

Circulating tumor DNA (ctDNA) holds great promise as a noninvasive biomarker for cancer diagnosis, treatment, and prognosis. However, the accurate and specific quantification of low-abundance ctDNA in serum remains a significant challenge. This study introduced, for the first time, a novel exponential amplification reaction (EXPAR)-assisted CRISPR/Cas12a-mediated ratiometric dual-signal electrochemical biosensor for ultrasensitive and reliable detection of ctDNA. To implement the dual-signal strategy, a signal unit (ssDNA-MB@Fc/UiO-66-NH 2 ) was prepared, consisting of methylene blue-modified ssDNA as the biogate to encapsulate ferrocene signal molecules within UiO-66-NH 2 nanocarriers. The presence of target ctDNA KRAS triggered EXPAR amplification, generating numerous activators for Cas12a activation, resulting in the cleavage of ssDNA-P fully complementary to the ssDNA-MB biogate. Due to the inability to form a rigid structure dsDNA (ssDNA-MB/ssDNA-P), the separation of ssDNA-MB biogate from the UiO-66-NH 2 surface was hindered by electrostatic interactions. Consequently, the…

Peroxynitrite (ONOO – ), as a short-term reactive biological oxidant, could lead to a series of effects in various physiological and pathological processes due to its subtle concentration changes. In vivo monitoring of ONOO – and relevant physiological processes is urgently required. Herein, we describe a novel fluorescent probe termed HBT-Fl-BnB for the ratiometric detection of ONOO – in vitro and in vivo. The probe consists of an HBT core with Fl groups at the ortho and para positions responding to the zwitterionic excited-state intramolecular proton-transfer (zwitterionic ESIPT) process and a boronic acid pinacol ester with dual roles that block the zwitterionic ESIPT and recognize ONOO – . Thanks to the specificity as well as low cytotoxicity, success in imaging of endogenous and exogenous ONOO – in living cells by HBT-Fl-BnB was obtained. Additionally, the applicability of HBT-Fl-BnB to tracking the abnormal expression of ONOO – in vivo induced by inactivated Escherichia coli was also explored. This is the first report of a fluorescent probe for ONOO – sensing via a…

Single-atom nanozymes (SAzymes) have been greatly developed for rapid detection, owing to their rich active sites and excellent catalytic activity. Although several excellent reviews concentrating on SAzymes have been reported, they mainly focused on advanced synthesis, sensing mechanisms, and biomedical applications. To date, few reviews elaborate on the promising applications of SAzymes in food safety inspection and food nutrition evaluation. In this paper, we systematically reviewed the enzyme-like activity of SAzymes and the catalytic mechanism, in addition to recent research advances of SAzymes in the domain of food safety inspection and food nutrition evaluation in the past few years. Furthermore, current challenges hampering practical applications of SAzymes in food assay are summarized and analyzed, and possible research areas focusing on SAzyme-based sensors in rapid food testing are also proposed.

Rapidly identifying and quantifying Gram-positive bacteria are crucial to diagnosing and treating bacterial lower respiratory tract infections (LRTIs). This work presents a field-deployable biosensor for detecting Gram-positive bacteria from exhaled breath condensates (EBCs) based on peptidoglycan recognition using an aptamer. Dielectrophoretic force is employed to enrich the bacteria in 10 s without additional equipment or steps. Concurrently, the measurement of the sensor’s interfacial capacitance is coupled to quantify the bacteria during the enrichment process. By incorporation of a semiconductor condenser, the whole detection process, including EBC collection, takes about 3 min. This biosensor has a detection limit of 10 CFU/mL, a linear range of up to 10 5 CFU/mL and a selectivity of 1479:1. It is cost-effective and disposable due to its low cost. The sensor provides a nonstaining, culture-free and PCR-independent solution for noninvasive and real-time diagnosis of Gram-positive bacterial LRTIs.

Surfactants are considered as typical emerging pollutants, their extensive use of in disinfectants has hugely threatened the ecosystem and human health, particularly during the pandemic of coronavirus disease-19 (COVID-19), whereas the rapid discrimination of multiple surfactants in environments is still a great challenge. Herein, we designed a fluorescent sensor array based on luminescent metal–organic frameworks (UiO-66-NH 2 @Au NCs) for the specific discrimination of six surfactants (AOS, SDS, SDSO, MES, SDBS, and Tween-20). Wherein, UiO-66-NH 2 @Au NCs were fabricated by integrating UiO-66-NH 2 (2-aminoterephthalic acid-anchored-MOFs based on zirconium ions) with gold nanoclusters (Au NCs), which exhibited a dual-emission features, showing good luminescence. Interestingly, due to the interactions of surfactants and UiO-66-NH 2 @Au NCs, the surfactants can differentially regulate the fluorescence property of UiO-66-NH 2 @Au NCs, producing diverse fluorescent “fingerprints”, which were further identified by pattern recognition methods. The proposed fluorescence sensor array…

Generally, rolling circle amplification (RCA) is based on an enzyme-linked padlock extension reaction. Herein, rapid linking that utilizes click chemistry for joining sticky ends of DNA molecules was developed. The ends of nucleic acid were modified with 2-cyano-6-aminobenzothiazole (CBT) and cystine (Cys–Cys), while glutathione was introduced to break the disulfide bond under target navigation and promote the linkage between CBT and Cys at the terminus of the nucleic acid at pH 7.4. Subsequently, RCA was performed using phi29 polymerase. CRISPR/Cas12a cleavage was triggered by the product of RCA amplification. Assisted by alkaline phosphatase, the electron exchange process between the photoelectroactive Sb@Co(OH)F nanorod and p -aminophenol ( p -AP) was collected in the form of photoelectrochemical (PEC) signals. Mass spectrometry, gel electrophoresis, and PEC signals were employed to verify the linking process and the RCA coupled with CRISPR/Cas12a cleavage amplification. CBT–Cys connection exhibited a high reaction rate (23.79 M –1 ·s –1 ). This enzyme-free linking process was…

MicroRNA (miRNA) detection is a critical aspect of disease diagnosis, and recent studies indicate that miRNA-622 could be a potential target for lung cancer. Herein, Cu single atoms were anchored on graphitic carbon nitride (Cu SAs@CN) as a coreaction accelerator applied in luminol-H 2 O 2 system, thereby establishing an efficient and sensitive electrochemiluminescence (ECL) biosensor for miRNA-622 detection. Cu SAs@CN was explored to possess excellent enzyme-like activities that promote the generation of abundant reactive oxygen species, which amplified ECL emission. Meanwhile, in order to improve the accuracy and sensitivity for miRNA-622 detection, the highly specific trans-cleavage ability of CRISPR/Cas12a was combined with a catalytic hairpin assembly strategy. Therefore, an ECL biosensor for miRNA-622 detection was systematically constructed as a proof of concept, achieving an ultralow limit of detection of 1.09 fM, and the feasibility was demonstrated in human serum samples. The findings of this research provide a promising strategy to enhance the ECL response using versatile…

In this work, we reported a cholesterol oxidase (Chox)-loaded platinum (Pt) nanozyme with the collaborative cascade nanoreactor for the construction of nanozyme–enzyme-linked immunosorbent assay (N-ELSA) models to realize high-throughput rapid evaluation of cancer markers. Considering the high specific surface area and manipulable surface sites, ZIF-8 was used as a substrate for natural enzyme and nanozyme loading. The constructed ZIF-8-Pt nanozyme platform exhibited efficient enzyme-like catalytic efficiency with a standard corrected activity of 60.59 U mg –1, which was 12 times higher than that of the ZIF-8 precursor, and highly efficient photothermal conversion efficiency (∼35.49%). In N-ELISA testing, developed multienzyme photothermal probes were immobilized in microplates based on antigen–antibody-specific reactions. Cholesterol was reacted in a cascade to reactive oxygen radicals, which attacked 3,3′,5,5′-tetramethylbenzidine, causing it to oxidize and color change, thus exhibiting highly enhanced efficient photothermal properties. Systematic temperature evaluations were…

Exploiting the multiple properties of nanozymes for the multimode lateral flow assay (LFA) is urgently required to improve the accuracy and versatility. Herein, we developed a novel plasmonic Au nanostar@PtOs nanocluster (Au@PtOs) as a multimode signal tag for LFA detection. Based on the PtOs bimetallic nanocluster doping strategy, Au@PtOs can indicate both excellent SERS enhancement and nanozyme catalytic activity. Meanwhile, Au@PtOs displays a better photothermal effect than that of Au nanostars. Therefore, catalytic colorimetric/SERS/temperature three-mode signals can be read out based on the Au@PtOs nanocomposite. The Au@PtOs was combined with LFA and applied for breast cancer exosome detection. The detection limit for the colorimetric/SERS/temperature mode was 2.6 × 10 3 /4.1 × 10 1 /4.6 × 10 2 exosomes/μL, respectively, which was much superior to the common Au nanoparticles LFA (∼10 5 exosomes/μL). Moreover, based on the fingerprint molecular recognition ability of the SERS mode, exosome phenotypes derived from different breast cancer cell lines can be discriminated easily.…

Rheumatoid arthritis (RA), a common chronic inflammatory illness, is still incurable, reducing the sufferers’ quality of life significantly. Adenosine 5′-triphosphate (ATP) and hypochlorous acid (HOCl) are key indicators in RA, but their precise mechanisms in RA pathophysiology are unknown. As a result, in order to detect ATP and HOCl simultaneously, we created two new dual-channel/localization single-molecule fluorescence probes, RhTNMB and RhFNMB . Furthermore, RhFNMB outperformed RhTNMB in terms of detection performance. ATP and HOCl produce independent fluorescence responses in the light red channel (λ ex = 520 nm, λ em = 586 nm) and deep red channel (λ ex = 620 nm, λ em = 688 nm), respectively, without spectral crosstalk. It should be noted that the probe RhFNMB successfully imaged ATP in mitochondria and HOCl in cells. Surprisingly, the probe RhFNMB demonstrated remarkable detection ability in the diagnosis and treatment of Pseudomonas aeruginosa -induced abdominal inflammation in mice. We continued to apply the probe RhFNMB to track ATP and HOCl in RA and discovered that ATP…

Exosomal miRNAs are considered promising biomarkers for cancer diagnosis, but their accuracy is severely compromised by the low content of miRNAs and the large amount of exosomal miRNAs released from normal cells. Here, we presented a dual-specific miRNA's logical recognition triggered by an entropy-driven catalysis (EDC)-enhanced system in exosomes for accurate detection of liver cancer-cell-derived exosomal miR-21 and miR-122. Taking advantage of the accurate analytical performance of the logic device, the excellent membrane penetration of gold nanoparticles, and the outstanding amplification ability of the EDC reaction, this method exhibits high sensitivity and selectivity for the detection of tumor-derived exosomal miRNAs in situ. Moreover, due to its excellent performance, this logic device can effectively distinguish liver cancer patients from healthy donors by determining the amount of cancer-cell-derived exosomal miRNAs. Overall, this strategy has great potential for analyzing various types of exosomes and provides a viable tool to improve the accuracy of cancer diagnosis.

Therapeutic oligonucleotides (ONs) commonly incorporate phosphorothioate (PS) modifications. These introduce chiral centers and generate ON diastereomers. The increasing number of ONs undergoing clinical trials and reaching the market has led to a growing interest to better characterize the ON diastereomer composition, especially for small interfering ribonucleic acids (siRNAs). In this study, and for the first time, we identify higher-order structures as the major cause of ON diastereomer separation in hydrophilic interaction chromatography (HILIC). We have used conformational predictions and melting profiles of several representative full-length ONs to first analyze ON folding and then run mass spectrometry and HILIC to underpin the link between their folding and diastereomer separation. On top, we show how one can either enhance or suppress diastereomer separation depending on chromatographic settings, such as column temperature, pore size, stationary phase, mobile-phase ionic strength, and organic modifier. This work will significantly facilitate future HILIC-based…

Identification of protein profiling on plasma exosomes by SERS can be a promising strategy for early cancer diagnosis. However, it is still challenging to detect multiple exosomal proteins simultaneously by SERS since the Raman signals of exosomes detected by conventional colloidal nanocrystals or two-dimensional SERS substrates are incomplete and complex. Herein, we develop a novel three-dimensional (3D) surround-enhancing SERS platform, named 3D se-SERS, for the multiplex detection of exosomal proteins. In this 3D se-SERS, proteins and exosomes are covered with "hotspots" generated by the gold nanoparticles, which surround the analytes densely and three-dimensionally, providing sensitive and comprehensive SERS signals. Combining this 3D se-SERS with a deep learning model, we successfully quantitatively profiled seven proteins including CD63, CD81, CD9, CD151, CD171, TSPAN8, and PD-L1 on the surface of plasma exosomes from patients, which can predict the occurrence and advancement of lung cancer. This 3D se-SERS integrating deep learning technique benefits from high sensitivity and…

Specific and sensitive detection of microRNAs continues to encounter significant challenges, especially in the development of rapid and efficient isothermal amplification strategies for point-of-care settings. The exponential amplification reaction (EXPAR) has garnered significant attention owing to its simplicity and rapid amplification of signals within a short period. However, a substantial loss of amplification efficiency, difficulty in distinguishing closely related homologous sequences, and adapting the designed templates to other targets seriously hamper the practical application of the EXPAR. In this work, a hairpin template tailored for the EXPAR system (exp-Hairpin) was constructed by adding identical trigger sequences and enzyme cleavage sites on two arms of the hairpin, achieving theoretically more than 2 n amplification efficiency and minimal background amplification of EXPAR. Modulating the stability of the exp-Hairpin template by increasing the stem length, the specificity of detecting target miRNA in highly homologous sequences could be significantly improved. Using…

An ultrahigh sensitive trace gas sensing system was presented with dual cantilever-based differential photoacoustic detection. By combining the double enhancement of multipass absorption and optical differential detection, the gas detection sensitivity was significantly improved. The dual-channel synchronous photoacoustic detection was realized by fiber-optic Fabry–Perot interference spectrum multiplexing. The photoacoustic signals detected by two fiber-optic cantilever microphones installed in a differential photoacoustic cell (DPAC) were out of phase, while the detected gas flow noises were in phase. The optical differential detection method achieved both highly sensitive optical interference measurement and differential noise suppression. In the multipass configuration, the interaction path between excitation light and target gas achieved 4.1 m, which improved the photoacoustic signal by an order of magnitude compared with a single reflection. The maximum gas flow allowed by the system based on the DPAC was 250 sccm, which realized the dynamic monitoring of H 2 S in the SF 6…

Lung cancer (LC) is the leading cause of cancer-related mortality worldwide, underscoring an urgent need for strategies that enable early detection and phenotypic classification. Here, we conducted a label-free surface-enhanced Raman spectroscopic (SERS) analysis of serum exosomes from 643 participants to elucidate the biochemical deregulation associated with LC progression and the unique phenotypes of different LC subtypes. Iodide-modified silver nanofilms were prepared to rapidly acquire SERS spectra with a high signal-to-noise ratio using 0.5 μL of patient exosomes. We performed interpretable and automated machine learning (ML) analysis of differential SERS features of serum exosomes to build LC diagnostic models, which achieved accuracies of 100% and 81% for stage I lung adenocarcinoma and its preneoplasia, respectively. In addition, the ML-derived exosomal SERS models effectively recognized different LC subtypes and disease stages to guide precision treatment. Our findings demonstrate that spectral fingerprinting of circulating exosomes holds promise for decoding the clinical…

Current nucleic acid-responsive DNA hydrogels face significant challenges, such as the requirement for high target concentrations, frequent redesigns, and increased costs, which limit their practical applications in biosensing. To address these issues, we developed a novel biosensing platform integrating a CRISPR/Cas12a system into an RCA-based DNA hydrogel. The hydrogel used in the platform could preencapsulate diverse signal molecules comprising GelRed, methylene blue, and gold nanoparticles, which were released upon Cas12a-mediated cleavage. This design enabled customizable signal output, including fluorescence, electrochemistry, and colorimetry, thereby ensuring the platform’s adaptability to various detection scenarios. Our platform was highly specific for methicillin-resistant Staphylococcus aureus, with a mecA gene detection limit of 10 copies/μL, and provided fast and accurate results within 2 h for clinical samples. Hence, based on these advantages, the proposed biosensing platform exhibits promising application prospects in the field of nucleic acid detection.

Wearable sweat sensors are reshaping healthcare monitoring, providing real-time data on hydration and electrolyte levels with user-friendly, noninvasive devices. This paper introduces a highly portable two-channel microfluidic device for simultaneous sweat sampling and the real-time detection of volatile organic compound (VOC) biomarkers. This innovative wearable microfluidic system is tailored for monitoring diabetes through the continuous and noninvasive tracking of acetone and ammonia VOCs, and it seamlessly integrates with smartphones for easy data management. The core of this system lies in the utilization of carbon polymer dots (CPDs) and carbon dots (CDs) derived from monomers such as catechol, resorcinol, o-phenylenediamine, urea, and citric acid. These dots are seamlessly integrated into hydrogels made from gelatin and poly­(vinyl alcohol), resulting in an advanced solid-state fluorometric sensor coating on a cellulose paper substrate. These sensors exhibit exceptional performance, offering linear detection ranges of 0.05–0.15 ppm for acetone and 0.25–0.37 ppm for ammonia,…

Uranium poses severe health risks due to its radioactivity and chemical toxicity if released into the environment. Therefore, there is an urgent demand to develop sensing materials in situ monitoring of uranium with high sensitivity and stability. In this work, a fluorescent Eu 3+ -TFPB-Bpy is synthesized by grafting Eu 3+ cation onto TFPB-Bpy covalent organic framework (COF) synthesized through Schiff base condensation of monomers 1,3,5-tris(4-formylphenyl)benzene (TFPB) and 5,5′-diamino-2,2′-bipyridine (Bpy). The fluorescence of Eu 3+ -TFPB-Bpy is enhanced compared with that of TFPB-Bpy, which is originated from the intramolecular rotations of building blocks limited by the bipyridine units of TFPB-Bpy coordinated with Eu 3+ . More significantly, Eu 3+ -TFPB-Bpy is a highly efficient probe for sensing UO 2 2+ in aqueous solution with the luminescence intensity efficiently amplified by complexation of UO 2 2+ with Eu 3+ . The turn-on sensing capability was derived from the resonance energy transfer occurring from UO 2 2+ to the Eu 3+ -TFPB-Bpy. The developed probe displayed…

CRISPR-Cas systems, harnessing their precise nucleic acid recognition via CRISPR RNA (crRNA), offer promise for the accurate testing of nucleic acids in the field. However, the inherent susceptibility of crRNA to degradation poses challenges for accurate detection in low-resource settings. Here, we utilized the chemically modified crRNA for the CRISPR-Cas-based assay (CM-CRISPR). We found that the extension and chemical modification to crRNA significantly enhanced the trans -cleavage activity of LbCas12a. The chemically modified crRNA was resistant to degradation, and CM-CRISPR showed superior detection capability in complex environments. CM-CRISPR could be combined with recombinase polymerase amplification (RPA) and applied in a droplet digital platform, enabling attomolar-level sensitivity. We also developed a portable and automated device for a digital CRISPR assay, which is amenable to point-of-care testing (POCT). The extraction-free procedure was integrated with this assay to streamline the workflow, and clinical samples were successfully detected. This work finds a simple and…