The 100 most-cited articles in Analytical Chemistry, 2019

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTRecent Advances in Photoelectrochemical Sensing: From Engineered Photoactive Materials to Sensing Devices and Detection ModesJian ShuJian ShuKey Laboratory of Analytical Science for Food Safety and Biology (MOE and Fujian Province), State Key Laboratory of Photocatalysis on Energy and Environment, Department of Chemistry, Fuzhou University, Fuzhou 350108, People's Republic of ChinaMore by Jian ShuView Biography and Dianping Tang*Dianping TangKey Laboratory of Analytical Science for Food Safety and Biology (MOE and Fujian Province), State Key Laboratory of Photocatalysis on Energy and Environment, Department of Chemistry, Fuzhou University, Fuzhou 350108, People's Republic of China*Phone: +86-591-2286 6125. Fax: +86-591-2286 6135. E-mail: [email protected]More by Dianping TangView Biographyhttp://orcid.org/0000-0002-0134-3983Cite this: Anal. Chem. 2020, 92, 1, 363–377Publication Date (Web):November 18, 2019Publication History Published online18 November 2019Published inissue 7 January…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTFiber-Optic Chemical Sensors and Biosensors (2015–2019)Xu-dong Wang*Xu-dong WangDepartment of Chemistry, Fudan University, 200433 Shanghai, P. R. China*E-mail: [email protected]More by Xu-dong WangView Biographyhttp://orcid.org/0000-0002-3402-7995 and Otto S. WolfbeisOtto S. WolfbeisInstitute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, D-93040 Regensburg, GermanyMore by Otto S. WolfbeisView BiographyCite this: Anal. Chem. 2020, 92, 1, 397–430Publication Date (Web):October 30, 2019Publication History Published online30 October 2019Published inissue 7 January 2020https://pubs.acs.org/doi/10.1021/acs.analchem.9b04708https://doi.org/10.1021/acs.analchem.9b04708review-articleACS PublicationsCopyright © 2019 American Chemical SocietyRequest reuse permissionsArticle Views7573Altmetric-Citations221LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTRecent Progress in Electrochemiluminescence Sensing and ImagingCheng MaCheng MaState Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. ChinaMore by Cheng MaView Biographyhttp://orcid.org/0000-0001-5729-8483, Yue CaoYue CaoState Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. ChinaMore by Yue CaoView Biographyhttp://orcid.org/0000-0002-8934-7195, Xiaodan GouXiaodan GouState Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. ChinaMore by Xiaodan GouView Biography, and Jun-Jie Zhu*Jun-Jie ZhuState Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China*E-mail: [email protected]More by Jun-Jie ZhuView Biographyhttp://orcid.org/0000-0002-8201-1285Cite this: Anal. Chem.…

Abstract Improvements in the performance and availability of commercial instrumentation have made ion mobility-mass spectrometry (IM-MS) an increasingly popular approach for the structural analysis of ionic species as well as for separation of complex mixtures. Here, a new research instrument is presented which enables complex experiments, extending the current scope of IM technology. The instrument is based on a Waters SYNAPT G2-Si IM-MS platform, with the IM separation region modified to accept a cyclic ion mobility (cIM) device. The cIM region consists of a 98 cm path length, closed-loop traveling wave (TW)-enabled IM separator positioned orthogonally to the main ion optical axis. A key part of this geometry and its flexibility is the interface between the ion optical axis and the cIM, where a planar array of electrodes provides control over the TW direction and subsequent ion motion. On either side of the array, there are ion guides used for injection, ejection, storage, and activation of ions. In addition to single and multipass separations around the cIM, providing selectable…

This work reports a ZIF-8 (ZIF: Zeolitic Imidazolate Framework)-assisted NaYF 4:Yb, [email protected] upconverter for the photoelectrochemical (PEC) biosensing of carcinoembryonic antigen (CEA) under near-infrared (NIR) irradiation on a homemade 3D-printed device with DNA walker-based amplification strategy. The composite photosensitive material NaYF 4:Yb, [email protected], as converter to transfer NIR import to photocurrent output, was driven from annealed NaYF 4:Yb, [email protected] Yb 3+ and Tm 3+ -codoped NaYF 4 (NaYF 4:Yb,Tm) converted NIR excitation into UV emission, matching with the absorption of ZnO for in situ excitation to generate the photocurrent. Upon target CEA introduction, the swing arm of DNA walker including the sequence of CEA aptamer carried out the sandwiched bioassembly with CEA capture aptamer on the G-rich anchorage DNA tracks-functionalized magnetic beads. Thereafter, DNA walker was triggered, and the swing arm DNA was captured by the G-rich anchorage DNA according to partly complementary pairing and Exonuclease III (Exo III) consumed anchorage DNA by a…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTAmbient Ionization Mass Spectrometry: Recent Developments and ApplicationsClara L. FeiderClara L. FeiderDepartment of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United StatesMore by Clara L. FeiderView Biography, Anna KriegerAnna KriegerDepartment of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United StatesMore by Anna KriegerView Biography, Rachel J. DeHoogRachel J. DeHoogDepartment of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United StatesMore by Rachel J. DeHoogView Biography, and Livia S. Eberlin*Livia S. EberlinDepartment of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States*E-mail: [email protected]More by Livia S. EberlinView Biographyhttp://orcid.org/0000-0002-3885-3215Cite this: Anal. Chem. 2019, 91, 7, 4266–4290Publication Date (Web):February 21, 2019Publication History Published online21 February 2019Published inissue 2 April…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTWater Analysis: Emerging Contaminants and Current IssuesSusan D. Richardson*Susan D. RichardsonDepartment of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29205, United States*E-mail: [email protected]More by Susan D. RichardsonView Biographyhttp://orcid.org/0000-0001-6207-4513 and Susana Y. KimuraSusana Y. KimuraDepartment of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4, CanadaMore by Susana Y. KimuraView BiographyCite this: Anal. Chem. 2020, 92, 1, 473–505Publication Date (Web):December 11, 2019Publication History Published online11 December 2019Published inissue 7 January 2020https://pubs.acs.org/doi/10.1021/acs.analchem.9b05269https://doi.org/10.1021/acs.analchem.9b05269review-articleACS PublicationsCopyright © 2019 American Chemical SocietyRequest reuse permissionsArticle Views12015Altmetric-Citations274LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals.…

Simultaneous detection of multiple tumor biomarkers is in great demand for early and accurate cancer diagnosis. A homogeneous electrochemical biosensor has been proven to possess high sensitivity, but achieving simultaneous detection of multiple tumor biomarkers is still a challenge. Herein, we develop a novel homogeneous electrochemical biosensor for simultaneous detection of multiple tumor biomarkers based on the functionalized metal–organic frameworks (MOFs). The functionalized MOFs were prepared by using porous UIO-66-NH 2 as nanocontainer to load electroactive dyes and dsDNA as a gatekeeper to cap MOFs. In this context, two functionalized MOFs (MB@UIO and TMB@UIO) were fabricated and applied to simultaneous detection of let-7a and miRNA-21, used as the proof-of-concept analytes. The recognition and hybridization of P X with target miRNAs impel the generation of RNA–DNA complexes, which separated from MOFs and allowed the electroactive dyes to be released. In comparison with the case when target miRNAs are absent, two stronger signals are recorded, and dependent on target miRNA…

A rapid and sensitive method is crucial for nucleic acid detection. Recently, RNA-guided CRISPR/Cas12a nuclease-based methods present great promise for nucleic acid detection. In the present methods, however, DNA amplification and subsequent Cas12a cleavage is separated and the whole process takes as long as 2 h. Most importantly, the uncapping operation increases the risk of aerosol contamination. In this study, we propose a CRISPR/Cas12a-based method named "Cas12aVDet" for rapid nucleic acid detection. By integrating recombinase polymerase amplification (RPA) with Cas12a cleavage in a single reaction system, the detection can be accomplished in 30 min and uncapping contamination can be avoided. The detection signal can be observed by the naked eye under blue light. This method could detect DNA at single molecule level and demonstrated 100% accuracy for mycoplasma contamination detection, presenting great potential for a variety of nucleic acid detection applications.

This work presented an innovative and rationally engineered palindromic molecular beacon (PMB) based "Z-scheme" photoelectrochemical (PEC) biosensing protocol for the selective screening of kanamycin (Kana) through DNA hybridization-induced conformational conversion. Interestingly, the ingeniously designed PMB integrated the multifunctional elements including recognition region, primer-like palindromic fragment, and polymerization-nicking template. The cosensitized structures consisted of CdS quantum dot functionalized hairpin DNA2 (QD-HP2) and region-selectively deposited gold nanoparticles onto {001} facets of bismuth oxychloride (BiOCl-Au). Compared with BiOCl-Au alone, the attachment of CdS QDs onto BiOCl-Au (i.e., BiOCl-Au-CdS QDs) exhibited evidently enhanced photocurrent intensity thanks to the synergistic effect of Z-scheme BiOCl-Au-CdS QDs. After incubation with target Kana, Kana-aptamer binding could induce the exposure of PMB region for hairpin DNA1 (HP1). The exposed palindromic tails hybridized with each other (like a molecular machine) to consume the substrates (dNTPs)…

This Feature simply introduces the history and mechanism of classical electrogenerated chemiluminescence (ECL) systems for the detection of biomolecules, highlights new advances and emerging fields of the ECL biosensing with recent illustrative examples, and presents the challenges and perspectives of ECL biosensing.

Evaluation of an analytical method is a fundamental problem in analytical chemistry, and it is never straightforward. In this article, we show a perspective for facing this issue using an original tool. We propose a model that allows one to evaluate any analytical method/procedure in a global manner. It refers to the RGB additive color model and uses three primary colors to represent three main attributes of the evaluated method: analytical performance - Red, compliance with the "green" chemistry principles - Green, and productivity/practical effectiveness - Blue. A final color of the method results from the additive synthesis of the primary colors. To simplify classifications, we propose the set of nine final colors of the method (white, magenta, cyan, yellow, red, green, blue, colorless/gray, and black). The model provides also a quantitative parameter, named the "method brilliance", which integrates all primary colors and treats them with varying importance, adjusted to the evaluation context and subjective user preferences. The evaluation is performed using standard Excel…

A simple, instrument-free, paper-based analytical device with dual-emission carbon dots (CDs) (blue CDs and red CDs) was developed for the semiquantitative, visual, and sensitive speciation analysis of lead ions in a real sample with a sensitive detection limit of 2.89 nM. When a paper strip was immersed into the sample solution, the blue fluorescence was quenched by Pb 2+ in solution, while the red fluorescence served as a background reference without color change, and significant color evolutions from blue to red were observed under the ultraviolet lamp, resulting in a semiquantitative visual detection. Furthermore, a smartphone was used in the visual detection of lead ions by identifying the RGB value of the fluorescent probe solution and corresponding paper strip. The application of smartphones and fluorescent paper strips has greatly shortened the detection time and reduced the cost of detection, providing a new strategy for the on-site and semiquantitative detection of heavy-metal ions in water samples.

Recently, in situ detection of hydrogen peroxide (H 2 O 2 ) generated from live cells have caused tremendous attention, because it is of great significance in the control of multiple biological processes. Herein, Fe–N–C single-atom nanozymes (Fe–N–C SAzymes) with intrinsic peroxidase-like activity were successfully prepared via high-temperature calcination using FeCl 2, glucose, and dicyandiamide as precursors. The Fe–N–C SAzymes with FeN x as active sites were similar to natural metalloproteases, which can specifically enhance the peroxidase-like activity rather than oxidase-like activity. Accordingly, owing to the excellent catalytic efficiency of the Fe–N–C SAzymes, colorimetric biosensing of H 2 O 2 in vitro was performed via a typical 3,3′,5,5′-tetramethylbenzidine induced an allochroic reaction, demonstrating the satisfactory specificity and sensitivity. With regard to the practical application, in situ detection of H 2 O 2 generated from the Hela cells by the Fe–N–C SAzymes was also performed, which can expand the applications of the newborn SAzymes.

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTRecent Advances in Droplet MicrofluidicsYun DingYun DingInstitute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zürich, SwitzerlandMore by Yun DingView Biographyhttp://orcid.org/0000-0002-7784-7758, Philip D. HowesPhilip D. HowesInstitute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zürich, SwitzerlandMore by Philip D. HowesView Biographyhttp://orcid.org/0000-0002-1862-8395, and Andrew J. deMello*Andrew J. deMelloInstitute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zürich, Switzerland* E-mail: [email protected]More by Andrew J. deMelloView Biographyhttp://orcid.org/0000-0003-1943-1356Cite this: Anal. Chem. 2020, 92, 1, 132–149Publication Date (Web):November 26, 2019Publication History Published online26 November 2019Published inissue 7 January 2020https://pubs.acs.org/doi/10.1021/acs.analchem.9b05047https://doi.org/10.1021/acs.analchem.9b05047review-articleACS…

Large-scale untargeted lipidomics experiments involve the measurement of hundreds to thousands of samples. Such data sets are usually acquired on one instrument over days or weeks of analysis time. Such extensive data acquisition processes introduce a variety of systematic errors, including batch differences, longitudinal drifts, or even instrument-to-instrument variation. Technical data variance can obscure the true biological signal and hinder biological discoveries. To combat this issue, we present a novel normalization approach based on using quality control pool samples (QC). This method is called systematic error removal using random forest (SERRF) for eliminating the unwanted systematic variations in large sample sets. We compared SERRF with 15 other commonly used normalization methods using six lipidomics data sets from three large cohort studies (832, 1162, and 2696 samples). SERRF reduced the average technical errors for these data sets to 5% relative standard deviation. We conclude that SERRF outperforms other existing methods and can significantly reduce the unwanted…

Herein, we report a complete additively manufactured (AM) electrochemical sensing platform. In this approach, a fully AM/3D-printed electrochemical system, using a conventional low-cost 3D printer (fused deposition modeling) fabricating both the conductive electrodes and the nonconductive/chemically inert electrochemical cell is reported. The electrodes (working, counter, and pseudo-reference) are AM using a conductive fused-filament comprised of a mixture of carbon black nanoparticles and polylactic acid (CB/PLA). AM components partially coated with silver ink presented a similar behavior to a conventional Ag/AgCl reference electrode. The performance of the AM working electrode was evaluated after a simple and fast polishing procedure on sandpaper and electrochemical activation in a NaOH solution (0.5 mol L –1 ). Following the electrochemical activation step, a considerable improvement in the electrochemical behavior (current intensity and voltammetric profile) was obtained for model analytes, such as dopamine, hexaammineruthenium(III) chloride, ferricyanide/ferrocyanide, uric…

Development of high-performance fiber-shaped wearable sensors is of great significance for next-generation smart textiles for real-time and out-of-clinic health monitoring. The previous focus has been mainly on monitoring physical parameters such as pressure and strains associated with human activities. Development of an enzyme-based non-invasive wearable electrochemical sensor to monitor biochemical vital signs of health such as the glucose level in sweat has attracted increasing attention recently, due to the unmet clinical needs for the diabetic patients. To achieve this, the key challenge lies in the design of a highly stretchable fiber with high conductivity, facile enzyme immobilization, and strain-insensitive properties. Herein, we demonstrate an elastic gold fiber-based three-electrode electrochemical platform that can meet the aforementioned criteria toward wearable textile glucose biosensing. The gold fiber could be functionalized with Prussian blue and glucose oxidase to obtain the working electrode and modified by Ag/AgCl to serve as the reference electrode; and the…

A high brightness red fluorescent probe ( S-BODIPY ) has been developed for the sensitive and specific imaging of HClO/ClO – in vitro and in vivo. This probe exhibits some distinctive features such as excellent resistance to photobleaching, a high fluorescence brightness, high selectivity, as well as a good biocompatibility. Upon oxidation of the thio-ether group into sulfoxide, the probe showed a noticeable ratiometric fluorescence response toward ClO – with fast response (within 30 s) and a low detection limit (59 nM). The probe demonstrated the successful imaging of exogenous and endogenous HClO/ClO – in living HeLa cells, zebrafish, and mice with high signal-to-noise ratios. S-BODIPY allows for the real-time monitoring the level of ClO – in living cells by ratiometric fluorescence imaging, opening up exciting prospects to develop red and even near-infrared BODIPYs with high brightness and good photostability for in vivo imaging.

Multiplexed detection of extracellular vesicle (EV)-derived microRNAs (miRNAs) plays a critical role in facilitating disease diagnosis and prognosis evaluation. Herein, we developed a highly specific nucleic acid detection platform for simultaneous quantification of several EV-derived miRNAs in constant temperature by integrating the advantages of a clustered regularly interspaced short palindromic repeats/CRISPR associated nucleases (CRISPR/Cas) system and rolling circular amplification (RCA) techniques. Particularly, the proposed approach demonstrated single-base resolution attributed to the dual-specific recognition from both padlock probe-mediated ligation and protospacer adjacent motif (PAM)-triggered cleavage. The high consistency between the proposed approach RCA-assisted CRISPR/Cas9 cleavage (RACE) and reverse transcription quantitative polymerase chain reaction (RT-qPCR) in detecting EV-derived miRNAs' abundance from both cultured cancer cells and clinical lung cancer patients validated its robustness, revealing its potentials in the screening, diagnosis, and prognosis of…

MicroRNAs (miRNAs) are a series of promising molecules that could regulate gene expression, while its expression level and type are strictly related to the early diagnosis, targeted therapy, and prognosis of diseases. Improved detection accuracy of miRNAs would lead to unprecedented progress in early treatment. Numerous methods to improve sensitivity have been proposed and confirmed valuable in miRNAs detection recently. However, the research which especially targets at improving detection specificity remains rare. This Feature gives a retrospective summary of the most common detection methods including Northern blot, reverse transcription quantitative polymerase chain reaction, next-generation sequencing, and microarray. Common methods play an important role in many aspects because of maturity and stability. However, the problem of specificity still exists. Then, this Feature summarizes breakthroughs in traditional techniques which are closely related to progressive methods to improve specificity. In addition, considerable studies focusing on improving accuracy are described in…

High Resolution Image Download MS PowerPoint Slide This study reports a microfluidic chip-based wearable colorimetric sensor for detecting sweat glucose. The device consisted of five microfluidic channels branching out from the center and connected to the detection microchambers. The microchannels could route the sweat excreted from the epidermis to the microchambers, and each of them was integrated with a check valve to avoid the risk of the backflow of the chemical reagents from the microchamber. The microchambers contained the pre-embedded glucose oxidase (GOD)–peroxidase– o -dianisidine reagents for sensing the glucose in sweat. It was found that the color change caused by the enzymatic oxidation of o -dianisidine could show a more sensitive response to the glucose than that of the conventional GOD–peroxidase–KI system. This sensor could perform five parallel detections at one time. The obtained linear range for sweat glucose was 0.1–0.5 mM with a limit of detection of 0.03 mM. The sensor was also used to detect the glucose in sweat samples from a group of subjects engaged in…

Most of the current exosome-analysis strategies are time-consuming and largely dependent on commercial extraction kit-based preisolation step, which requires extensive sample manipulations, costly isolation kits, reagents, tedious procedures, and sophisticated equipment and is prone to bias/artifacts. Herein we introduce a simple method for direct isolation and subsequent detection of a specific population of exosomes using an engineered superparamagnetic material with multifunctional properties, namely, gold-loaded ferric oxide nanocubes (Au-NPFe 2 O 3 NC). In this method, the Au-NPFe 2 O 3 NC were initially functionalized with a generic tetraspanin (exosomes-associated) antibody (i.e., CD63) and dispersed in sample fluids where they work as “dispersible nanocarriers” to capture the bulk population of exosomes. After magnetic collection and purification, Au-NPFe 2 O 3 NC-bound exosomes were transferred to the tissue-specific, antibody-modified, screen-printed electrode. As a proof of principle, we used a specific placental marker, placenta alkaline phosphatase (PLAP), to detect…

Surface-enhanced Raman spectroscopy (SERS) is a promising analytical tool, but simultaneous detection of multiple targets using SERS remains a challenge. Herein, a cauliflower-inspired 3D SERS substrate with intense hot spots was prepared through sputtering Au nanoparticles (Au NPs) on the surface of polydimethylsiloxane coated anodic aluminum oxide (PDMS@AAO) complex substrate. As a result, the cauliflower-inspired 3D SERS substrate achieved the highest SERS activities at a sputtering time of 8 min. Under the optimal conditions, this SERS substrate possessed a low detection limit of 10 –12 M, excellent enhancement uniformity (relative standard deviation, RSD = 4.57%) and high enhancement factor (2.2 × 10 6 ) for 4-mercaptobenzoic acid (4-MBA). Furthermore, the results of Raman showed that the 3D-Nanocauliflower SERS substrates could realize the simultaneous label-free detection for three mycotoxins (aflatoxin B 1, deoxynivalenol, and zearalenone) in maize for the first time. It behaved good linear relationship between the concentrations and Raman intensities of aflatoxin B 1,…

Diabetic ketoacidosis (DKA), a severe complication of diabetes mellitus with potentially fatal consequences, is characterized by hyperglycemia and metabolic acidosis due to the accumulation of ketone bodies, which requires people with diabetes to monitor both glucose and ketone bodies. However, despite major advances in diabetes management mainly since the emergence of new-generation continuous glucose monitoring (CGM) devices capable of in vivo monitoring of glucose directly in the interstitial fluid (ISF), the continuous monitoring of ketone bodies is yet to be addressed. Here, we present the first use of a real-time continuous ketone bodies monitoring (CKM) microneedle platform. The system is based on the electrochemical monitoring of β-hydroxybutyrate (HB) as the dominant biomarker of ketone formation. Such real-time HB detection has been realized using the β-hydroxybutyrate dehydrogenase (HBD) enzymatic reaction and by addressing the major challenges associated with the stable confinement of the enzyme/cofactor couple (HBD/NAD + ) and with a stable and selective low-potential…

Nanomaterials with enzyme-like characteristics (nanozymes) have been developed to mimic enzymes because of their low cost, high stability, and large-scale production. By using light as an external stimulation, one can modulate nanozymes’ catalytic activities with controlled spatial and temporal precision. A few inorganic photoactive materials have been investigated to construct light-responsive oxidase-like nanozymes. However, these materials suffered from limited absorbance of visible light. To address this challenge, herein we have developed a photosensitized metal–organic framework (PSMOF) by using a derivative of Ru(bpy) 3 2+ with stronger visible-light absorption as a PS linker. The PSMOF exhibited excellent oxidase-like activity, which could be modulated by switching light on and off. Moreover, the PSMOF was used to detect glutathione levels in both normal and cancer cells with good selectivity and high sensitivity. This study not only provides a smart strategy to modulate nanozymes’ activities but also broadens the sensing applications of nanozymes.

This work developed a near-infrared (near-IR) light-activated non-enzymatic signal-off photoelectrochemical (PEC) immunoassay for the ultrasensitive detection of α-fetoprotein (AFP) on the basis of branched polyethylenimine (BPEI)-modified upconversion nanoparticle (UCNP)@CdTe quantum dot (QD) nanostructures by coupling with the synergistic effect of dual-purpose copper ions. Emission light originated from NaYF 4:Yb,Er UCNP was directly utilized through the electrostatic bonding of CdTe QDs to excite the separation of electron–hole pairs, resulting in the generation of obvious photocurrent under a 980 nm laser. By using polyclonal antibody-labeled cupric oxide nanoparticle as the secondary antibody, the nanolabel was introduced into the monoclonal anti-AFP antibody-modified microplates in the presence of target AFP. After treatment with acid, the as-released copper ion decreased the photocurrent through the synergistic effect with two issues: one was initially to form coordination with BPEI on the surface of UCNP, and then the near-IR excitation light and upconversion luminescence…

The intracellular viscosity is closely related to many functional disorders and diseases. Especially, abnormal mitochondrial viscosity changes are one of the distinct indications in metabolite diffusion as well as mitochondrial metabolism. In this work, we report a novel fluorescent probe (NI-VIS), which uses quinoline as an acceptor group and employs a TICT mechanism (twisted intramolecular charge transfer) to detect viscosity. NI-VIS features a good mitochondrion targeting ability and near-infrared emission. NI-VIS possesses a highly sensitive response toward viscosity changes in aqueous environments. As the viscosity of a DPBS-glycerol system increased from 1.0 to 999 cP, NI-VIS exhibited a hundred-fold enhancement in fluorescence. We demonstrated that after the treatment with ionophores, NI-VIS could identify the variation of mitochondrial viscosity in HeLa cells. The probe also recognized the decrease of mitochondria viscosity during starvation-induced mitophagy. More importantly, NI-VIS was successfully applied to visualize the viscosity variation in cirrhotic liver tissues.…

With the introduction of gas-based contactless electrochemical biosensors lies the prospects of separating the sensing interface from the bioassembly platform, enhancing stability, and exploring signal transduction mechanism, all intimately linking to development of immunoassay. Herein, we report on a H 2 -based electrochemical biosensor whose signals derived from the chemical signal transduction between a H 2 and Pd nanowires@ZIF-67 (ZIF: Zeolitic Imidazolate Frameworks) bilayered sensing interface for immunoassay. Dendritic Pt nanoparticles (DPNs) conjugated on the detection antibody were introduced on the interface of a magnetic microsphere according to an immune sandwich assembly between the antigen and antibody. H 2 as a bridge originates from DPNs catalyzing NH 3 BH 3 and links biological signals to electrical signals by reacting with Pd nanowires. Nevertheless, the response of Pd nanowires being extremely effected by O 2 in air due to the competitive adsorption on the surface of Pd nanostructures as well as the reaction between chemisorbed O (Pd–O) and adsorbed dihydrogen…

Imaging mass spectrometry (IMS) enables the spatially targeted molecular assessment of biological tissues at cellular resolutions. New developments and technologies are essential for uncovering the molecular drivers of native physiological function and disease. Instrumentation must maximize spatial resolution, throughput, sensitivity, and specificity, because tissue imaging experiments consist of thousands to millions of pixels. Here, we report the development and application of a matrix-assisted laser desorption/ionization (MALDI) trapped ion-mobility spectrometry (TIMS) imaging platform. This prototype MALDI timsTOF instrument is capable of 10 μm spatial resolutions and 20 pixels/s throughput molecular imaging. The MALDI source utilizes a Bruker SmartBeam 3-D laser system that can generate a square burn pattern of <10 × 10 μm at the sample surface. General image performance was assessed using murine kidney and brain tissues and demonstrate that high-spatial-resolution imaging data can be generated rapidly with mass measurement errors <5 ppm and ∼40 000 resolving power. Initial…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTWearable Chemical Sensors: Emerging Systems for On-Body Analytical ChemistryJuliane R. SempionattoJuliane R. SempionattoDepartment of Nanoengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United StatesMore by Juliane R. SempionattoView Biography, Itthipon JeerapanItthipon JeerapanDepartment of Nanoengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United StatesMore by Itthipon JeerapanView Biographyhttp://orcid.org/0000-0001-8016-6411, Sadagopan KrishnanSadagopan KrishnanDepartment of Nanoengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United StatesDepartment of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United StatesMore by Sadagopan KrishnanView Biographyhttp://orcid.org/0000-0002-9968-2712, and Joseph Wang*Joseph WangDepartment of Nanoengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States*E-mail: [email protected]More by…

Multiplexed, isobaric tagging methods are powerful techniques to increase throughput, precision, and accuracy in quantitative proteomics. The dynamic range and accuracy of quantitation, however, can be limited by coisolation of tag-containing peptides that release reporter ions and conflate quantitative measurements across precursors. Methods to alleviate these effects often lead to the loss of protein and peptide identifications through online or offline filtering of interference containing spectra. To alleviate this effect, high-Field Asymmetric-waveform Ion Mobility Spectroscopy (FAIMS) has been proposed as a method to reduce precursor coisolation and improve the accuracy and dynamic range of multiplex quantitation. Here we tested the use of FAIMS to improve quantitative accuracy using previously established TMT-based interference standards (triple-knockout [TKO] and H uman- Y east P rot e omics R esource [HYPER]). We observed that FAIMS robustly improved the quantitative accuracy of both high-resolution MS 2 (HRMS 2 ) and synchronous precursor selection MS 3 (SPS-MS 3 )-based…

Human norovirus (NoV) remains the most common cause of viral gastroenteritis and the leading cause of viral foodborne outbreaks globally. NoV is highly pathogenic with an estimated median viral infective dose (ID 50 ) ranging from 18 to 1015 genome copies. For NoV detection, the only reliable and sensitive method available for detection and quantification is reverse transcription quantitative polymerase chain reaction (RTqPCR). NoV detection in food is particularly challenging, requiring matrix specific concentration of the virus and removal of inhibitory compounds to detection assays. Hence, the RTqPCR method poses some challenges for rapid in-field or point-of-care diagnostic applications. We propose a new colorimetric NanoZyme aptasensor strategy for rapid (10 min) and ultrasensitive (calculated Limit of Detection (LoD) of 3 viruses per assay equivalent to 30 viruses/mL of sample and experimentally demonstrated LoD of 20 viruses per assay equivalent to 200 viruses/mL) detection of the infective murine norovirus (MNV), a readily cultivable surrogate for NoV. Our approach combines…

Wearable sensors for noninvasive monitoring of physiological parameters is a growing technology in the clinical field. Especially in neonates, the development of portable and nonharmful monitoring devices is urgently needed because they cannot provide any feedback about discomfort or health complaints. However, in infant monitoring, only wearable sensors measuring physical parameters for vital signs have been developed. Here, we describe the first chemical wearable sensor for newborn monitoring. This fully integrated pacifier operates as a portable wireless device toward noninvasive chemical monitoring in the infant's saliva. The infant's mouth movements on the pacifier result in efficient saliva pumping and promote unidirectional flow from the mouth to the electrochemical chamber. The integrated electrochemical detection chamber, containing the enzymatic biosensor, is located outside of the oral cavity. The capabilities of the platform were studied for glucose detection in diabetic adults and compared to their blood levels with good correlation, demonstrating the sensor's good…

Exosomes (Exos) are nanoscale natural vehicles for transporting biomolecules to facilitate cell-to-cell communication, indicating a high potential of them for delivering therapeutics/diagnostics. To improve their delivery capacity, a simple, noninvasive, and efficient strategy for functionalizing Exos with effective targeting ligands as well as elucidation of the cellular uptake mechanism of these functionalized Exos was found be to necessary, but remained a challenge. In this work, we used diacyllipid-aptamer conjugates as the targeting ligand to develop an aptamer-functionalized Exos (Apt-Exos) nanoplatform for cell type-specific delivery of molecular therapeutics. The cellular uptake mechanism of Apt-Exos was investigated in details, and distinct behavior was observed in comparison to free Exos. By combining the excellent molecular recognition capability of aptamers and the superiority of Exos as natural vehicles, Apt-Exos can efficiently deliver molecular drugs/fluorophores to target cancer cells, providing a promising delivery platform for cancer theranostics.

Ferric ion (Fe 3+ ) plays a vital role in cellular homeostasis. However, the detection of Fe 3+ with rhodamine B (RhB) has potential problems, such as poor selectivity and low photostability. To address these problems, we rationally designed an RhB@MOF nanocomposite-based “on–off–on” fluorescent switching nanoprobe for highly sensitive and selective detection of Fe 3+ and ascorbic acid. This RhB@MOF nanoprobe was prepared through a facile one-pot synthesis. Here MOF served as a selectivity regulator for the detection of Fe 3+ . By embedding RhB into the porous crystalline MOF, enhanced photostability and fluorescence lifetime of RhB to Fe 3+ were achieved. The as-prepared RhB@MOF was demonstrated to be an ultrasensitive and selective nanoprobe for the detection of Fe 3+ in human serum and ascorbic acid in rat brain microdialysate. Furthermore, inner filter effect (IFE) and photoinduced electron transfer (PET) were proposed and discussed to explain the selectivity and sensitivity of RhB to Fe 3+ against other interfering substances. Our novel “on–off–on” nanoprobe provides insight…

MicroRNAs (miRNAs) are short noncoding RNAs that post-transcriptionally regulate gene expression. It has been proved that the aberrant expression of miRNAs is related to disease and miRNAs can serve as potential biomarkers for early tumor diagnosis. The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas13a is a recently discovered CRISPR-RNA (crRNA) guided RNA manipulation tool. The recognition of target RNA can morphologically activate the robust nonspecific trans ribonuclease activity of Cas13a. This unique property makes Cas13a ideal for nucleic acid detection. Herein, we first exploited CRISPR/LbuCas13a to directly detect miRNAs with high specificity and simplicity. A limit of detection (LOD) as low as 4.5 amol was achieved by this one-step assay within 30 min, and the dynamic range spanned 4 orders of magnitude from 10 amol to 100 fmol. More importantly, single nucleotide variation, even at the end of target miRNA, can be discriminated by rationally programmed crRNA. In addition, the practical application ability of this Cas13a/crRNA-based signal…

The development of an analytical method for selective and sensitive detection of chlortetracycline (CTC), an often overused broad spectrum antibiotic, is important and challenging in environmental and health monitoring. This paper reports a zinc based metal-organic framework of pyromellitic acid (Zn-BTEC), which has been found to greatly enhance the aggregation-induced emission (AIE) of chlortetracycline. The unique emission response of CTC on Zn-BTEC has been extensively examined and applied for the sensitive detection of CTC on the basis of fluorescence intensity of AIE, and a limit of detection (LOD) was estimated to be 28 nM. A rational mechanism has been proposed based on the porous structure of Zn-BTEC, and the CTC molecules would defuse into the rigid MOF structure and assemble or aggregate, leading to fluorescence enhancement of CTC. Interestingly, the Zn-BTEC materials could discriminate CTC from other TC antibiotics with high selectivity. We have further demonstrated that the Zn-BTEC materials are successfully applied for the sensitive and selective determination of CTC in…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTSignal Amplification in Living Cells: A Review of microRNA Detection and ImagingHanyong PengHanyong PengDivision of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, 10-102 Clinical Sciences Building, Edmonton, Alberta T6G 2G3, CanadaMore by Hanyong PengView Biography, Ashley M. NewbiggingAshley M. NewbiggingDivision of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, 10-102 Clinical Sciences Building, Edmonton, Alberta T6G 2G3, CanadaMore by Ashley M. NewbiggingView Biography, Michael S. ReidMichael S. ReidDivision of Analytical and Environmental Toxicology, Department of Laboratory Medicine and Pathology, Faculty of Medicine and Dentistry, University of Alberta, 10-102 Clinical Sciences Building, Edmonton, Alberta T6G 2G3, CanadaMore by Michael S. ReidView Biography, Jagdeesh S. UppalJagdeesh S. UppalDivision of Analytical and Environmental…

High Resolution Image Download MS PowerPoint Slide This letter is devoted to the application of machine learning, namely, convolutional neural networks to solve problems in the initial steps of the common pipeline for data analysis in metabolomics. These steps are the peak detection and the peak integration in raw liquid chromatography–mass spectrometry (LC–MS) data. Widely used algorithms suffer from rather poor precision for these tasks, yielding many false positive signals. In the present work, we developed an algorithm named peakonly, which has high flexibility for the detection or exclusion of low-intensity noisy peaks, and shows excellent quality in the detection of true positive peaks, approaching the highest possible precision. The current approach was developed for the analysis of high-resolution LC–MS data for the purposes of metabolomics, but potentially it can be applied with several adaptations in other fields, which utilize high-resolution GC− or LC–MS techniques. Peakonly is freely available on GitHub ( https://github.com/arseha/peakonly ) under an MIT license.

N-doping strategy has been explored to enhance the activity of carbon nanozymes because the reconstructed electronic structures in N-doped carbon nanozymes are advantageous for the catalytic process. However, carbon nanozymes with high N content are still difficult to obtain due to the instability of N element under high calcination temperatures. To address this challenge, here we proposed a new N-doping strategy to fabricate highly active and specific peroxidase-like carbon nanozymes by using a high N-containing polymer (i.e., polyethylenimine (PEI)) as the N source and a natural clay mineral (i.e., montmorillonite (MMT)) as a template, respectively. We showed that the assembly of MMT with PEI protected N loss under high calcination temperatures and thus retained more catalytically active N sites. The mechanism study showed that the hydroxyl radical could be the key intermediate involved in the peroxidase-like catalysis. We then used the optimized carbon nanozyme with high and specific peroxidase-like activity (i.e., CP 600–6 ) to detect H 2 O 2, glucose, and ascorbic acid.…

Effective extension of mass spectrometry-based proteomics to single cells remains challenging. Herein we combined microfluidic nanodroplet technology with tandem mass tag (TMT) isobaric labeling to significantly improve analysis throughput and proteome coverage for single mammalian cells. Isobaric labeling facilitated multiplex analysis of single cell-sized protein quantities to a depth of ∼1 600 proteins with a median CV of 10.9% and correlation coefficient of 0.98. To demonstrate in-depth high throughput single cell analysis, the platform was applied to measure protein expression in 72 single cells from three murine cell populations (epithelial, immune, and endothelial cells) in <2 days instrument time with over 2 300 proteins identified. Principal component analysis grouped the single cells into three distinct populations based on protein expression with each population characterized by well-known cell-type specific markers. Our platform enables high throughput and unbiased characterization of single cell heterogeneity at the proteome level.

While breakthroughs in peroxidase-like nanozymes for bioanalysis have been made, most of current nanozyme biosensing systems are based on a single signal output. Such sensing systems could be easily influenced by environmental and personal factors. We envision that nanozyme sensing systems with ratiometric signal outputs would provide more reliable and robust sensing performance. Herein, to construct such ratiometric sensing systems, three fluorescent graphitic carbon nitride (C 3 N 4 )-based nanozymes (i.e., C 3 N 4 –Ru, C 3 N 4 –Cu, and C 3 N 4 –hemin) with excellent peroxidase-like activities were prepared. These fluorescent nanozymes emitted a fluorescence at 438 nm when excited at 385 nm. Interestingly, when o -phenylenediamine (OPD) was catalytically oxidized to oxidized OPD (OPDox) in the presence of H 2 O 2 and nanozymes, the OPDox not only emitted an emerging fluorescence at 564 nm but also quenched the fluorescence at 438 nm of the nanozymes. We therefore employed the ratio of the fluorescent intensity at 564 and 438 nm (i.e., F 564 / F 438 ) as the signal output to…

Lipids are highly diverse biomolecules associated with several biological functions including structural constituent, energy storage, and signal transduction. It is essential to characterize lipid structural isomers and further understand their biological roles. Unsaturated lipids contain one or multiple carbon-carbon double bonds. Identifying double bond position presents a major challenge in unsaturated lipid characterization. Recently, several advancements have been made for double bond localization by mass spectrometry (MS) analysis. However, many of these studies require complex chemical reactions or advanced mass spectrometers with special fragmentation techniques, which limits the application in lipidomics study. Here, an innovative meta-chloroperoxybenzoic acid ( m-CPBA) epoxidation reaction coupling with collision-induced dissociation (CID)-MS/MS strategy provides a new tool for unsaturated lipidomics analysis. The rapid epoxidation reaction was carried out by m-CPBA with high specificity. Complete derivatization was achieved in minutes without overoxidized byproduct.…

Wearable biosensors as a user-friendly measurement platform have become a rapidly growing field of interests due to their possibility in integrating traditional medical diagnostics and healthcare management into miniature lab-on-body analytic devices. This paper demonstrates a flexible and skin-mounted band that combines superhydrophobic-superhydrophilic microarrays with nanodendritic colorimetric biosensors toward in situ sweat sampling and analysis. Particularly, on the superwettable bands, the superhydrophobic background could confine microdroplets into superhydrophilic microwells. On-body investigations further reveal that the secreted sweat is repelled by the superhydrophobic silica coating and precisely collected and sampled onto the superhydrophilic micropatterns with negligible lateral spreading, which provides an independent "vessel" toward cellphone-based sweat biodetection (pH, chloride, glucose and calcium). Such wearable, superwettable band-based biosensors with improved interface controllability could significantly enhance epidemical sweat sampling in well-defined…

High Resolution Image Download MS PowerPoint Slide The enzyme-linked immunosorbent assay (ELISA) is a basic technique used in analytical and clinical investigations. However, conventional ELISA is still not sensitive enough to detect ultralow concentrations of biomarkers for the early diagnosis of cancer, cardiovascular risk, neurological disorders, and infectious diseases. Herein we show a mechanism utilizing the CRISPR/Cas13a-based signal export amplification strategy, which double-amplifies the output signal by T7 RNA polymerase transcription and CRISPR/Cas13a collateral cleavage activity. This process is termed the CRISPR/Cas13a signal amplification linked immunosorbent assay (CLISA). The proposed method was validated by detecting an inflammatory factor, human interleukin-6 (human IL-6), and a tumor marker, human vascular endothelial growth factor (human VEGF), which achieved limit of detection (LOD) values of 45.81 fg/mL (2.29 fM) and 32.27 fg/mL (0.81 fM), respectively, demonstrating that CLISA is at least 10 2 -fold more sensitive than conventional ELISA.

Ochratoxin A (OTA), a toxic mycotoxin, poses severe risks to environment and human health. Herein, we develop a ratiometric surface-enhanced Raman scattering (SERS) aptasensor based on internal standard (IS) methods for the sensitive and reproducible quantitative detection of OTA. Au-Ag Janus nanoparticles (NPs) are successfully synthesized under the guidance of 2-mercaptobenzoimidazole-5-carboxylic acid (MBIA), which possesses intrinsic Raman signals, thus no additional modification with a Raman reporter on NPs is required. In addition, Au-Ag Janus NPs exhibit amplified and stable SERS activity. MXenes nanosheets generate a unique and stable Raman signal, making them an ideal IS for quantitative Raman analysis. In principle, Au-Ag Janus NPs are assembled with MXenes nanosheets depending on hydrogen bond and the chelation interaction between MXenes nanosheets and OTA aptamers. In the presence of OTA, Au-Ag Janus NPs are dissociated from MXenes nanosheets due to the formation of aptamer/OTA complex, leading to the attenuation of Raman signal of Au-Ag Janus NPs, and meanwhile, the…

Urine metabolites are used in many clinical and biomedical studies but usually only for a few classic compounds. Metabolomics detects vastly more metabolic signals that may be used to precisely define the health status of individuals. However, many compounds remain unidentified, hampering biochemical conclusions. Here, we annotate all metabolites detected by two untargeted metabolomic assays, hydrophilic interaction chromatography (HILIC)-Q Exactive HF mass spectrometry and charged surface hybrid (CSH)-Q Exactive HF mass spectrometry. Over 9,000 unique metabolite signals were detected, of which 42% triggered MS/MS fragmentations in data-dependent mode. On the highest Metabolomics Standards Initiative (MSI) confidence level 1, we identified 175 compounds using authentic standards with precursor mass, retention time, and MS/MS matching. An additional 578 compounds were annotated by precursor accurate mass and MS/MS matching alone, MSI level 2, including a novel library specifically geared at acylcarnitines (CarniBlast). The rest of the metabolome is usually left unannotated. To fill…

Drug-induced hepatotoxicity represents an important challenge for safety in drug development. The production of peroxynitrite (ONOO – ) is proposed as an early sign in the progression of drug-induced hepatotoxicity. Currently, reported ONOO – probes mainly emit in the visible range or the first NIR window, which have limited in vivo biosensing application due to the autofluorescence and photon scattering. Herein, we developed a peroxynitrite activatable second near-infrared window (NIR-II) molecular probe for drug-induced hepatotoxicity monitoring, based on the fusion of an NIR-II fluorescence turn-on benzothiopyrylium cyanines skeleton and the phenyl borate. In the presence of ONOO –, the probe IRBTP-B can turn on its NIR-II fluorescence by yielding its fluorophore IRBTP-O and display good linear response to ONOO – . Tissue phantom study confirmed reliable activated signals could be acquired at a penetration depth up to 5 mm. Using this probe, we disclose the upregulation of ONOO – in a preclinical drug-induced liver injury model and the remediation with N-acetyl cysteine (NAC) in…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTSample Preparation Using Molecularly Imprinted PolymersValérie Pichon*Valérie PichonLaboratoire des Sciences Analytiques, Bioanalytiques et Miniaturisation−UMR Chimie Biologie Innovation 8231, ESPCI Paris, CNRS, PSL* Research University, 10 rue Vauquelin, 75005 Paris, FranceSorbonne Université, 75005 Paris, France*E-mail: [email protected]. Phone: +33 140 794 772. Fax: +33 140 794 776.More by Valérie PichonView Biographyhttp://orcid.org/0000-0002-9232-2861, Nathalie DelaunayNathalie DelaunayLaboratoire des Sciences Analytiques, Bioanalytiques et Miniaturisation−UMR Chimie Biologie Innovation 8231, ESPCI Paris, CNRS, PSL* Research University, 10 rue Vauquelin, 75005 Paris, FranceMore by Nathalie DelaunayView Biography, and Audrey CombèsAudrey CombèsLaboratoire des Sciences Analytiques, Bioanalytiques et Miniaturisation−UMR Chimie Biologie Innovation 8231, ESPCI Paris, CNRS, PSL* Research University, 10 rue Vauquelin, 75005 Paris, FranceMore by Audrey CombèsView BiographyCite this: Anal. Chem. 2020, 92, 1, 16–33Publication Date (Web):November…

Elucidating the internal relationship between diseases and mitochondrial viscosity remains a great challenge due to the lack of the studies on multidisease living animals. So far, demonstrating abnormal mitochondria viscosity in the fatty liver and tumor living mice has not been achieved. To address this critical challenge, the powerful two-photon and mitochondria-targeted fluorescence probe CBI-V was designed herein for viscosity detection with deep red emission. Utilizing the new probe CBI-V, the mitochondrial viscosity alteration in living systems caused by monensin or nystatin has been monitored sensitively and selectively in real time. Moreover, the probe is capable of imaging mitochondrial viscosity in the inflammatory models at the cell, zebrafish, and mice level. Importantly, the visualization of mitochondrial viscosity has been achieved in both fatty liver and tumor living mice for the first time. This work not only advances the study of the relationship between disease and mitochondrial viscosity but also opens up an efficient way for diagnosing mitochondrial viscosity…

The design and synthesis of a proline-based reporter isobaric Tandem Mass Tag structure (TMTpro) is presented. An analysis is made of the performance of the new TMTpro tags in comparison with the current commercially available dimethylpiperidine-reporter-based TMT10/11 reagents. The new reporter structure provides a set of 16 tags for use with resolution of 6.3 mDa mass differences in high resolution mass spectrometers and a set of 9 reagents with 1 Da spacing between reporter ions for single dalton analysis using 9 heavy nuclei per tag. We show similar performance in terms of peptide identification rates and quantification between the TMTpro 16-plex and TMT10/11-plex reagents. We also demonstrate the suitability of the TMTpro reagents for phosphopeptide analysis. The ability to pool 16 samples reduces the overall amount of sample required for each channel, and we anticipate that TMTpro reagents will be a useful enhancement for any protocol that benefits from sample pooling and should reduce missing data.

Enzymatic biofuel cell (EBFC)-based self-powered biosensors could offer significant advantages: no requirement for an external power source, simple instruments, and easy miniaturization. However, they also suffered from the limitations of lower sensitivity or specific targets. In this study, a self-powered biosensor for the ultrasensitive and selective detection of single nucleotide polymorphisms (SNPs) produced by combining the toehold-mediated strand displacement reaction (SDR) and DNA hybridization chain reaction (HCR) was proposed. Herein, the capture probe (CP) with an external toehold was designed to switch on the sensing system. In the presence of target sequence, both SDR and DNA HCR reaction would happen to produce a long double-helix chain. Because of the electrostatic interaction between [Ru(NH 3 ) 6 ] 3+ and the double-helix chain described above, the open circuit voltage ( E OCV ) of the as-proposed biosensor was significantly elevated, thus realizing the detection of SNPs. Overall, in this work, an ingeniously constructed self-powered biosensor for the detection of…

Mitochondria, powerhouses of cells, possess a weakly alkaline environment. Various stress stimulations may lead to mitophagy, which further gives a rise to mitochondrial acidification and disfunction. Therefore, monitoring mitochondrial pH alterations is of great importance to better elucidate their role in the cellular metabolism. Toward this end, a number of mitochondrial fluorescent pH probes have been proposed, but most of them are based on electrostatic attraction and readily leak out from the mitochondria during mitophagy with decreased membrane potential, thus failing to accurately measure the pH changes. In this work, we report a mitochondria-immobilized ratiometric fluorescent pH probe, which allows the quantitative measurements of mitochondrial pH. The probe was designed and prepared by introducing a reactive benzyl chloride into a positively charged near-infrared hydroxyl-hemicyanine. The cationic property facilitates the probe to be quickly enriched into mitochondria, the hydroxyl group is responsible for producing a reversible ratiometric fluorescence signal, and benzyl…

Hypochlorite (ClO – ) and ascorbic acid (AA) are reported to have a high correlation with oxidative stress and related diseases, so it is necessary and critical to develop sensitive and fast response sensors to investigate the dynamical variation of these redox substances, especially those sensors which can detect ClO – and AA in real time in two manners. However, it is still an unmet challenge for now. Herein, novel carbon dots (RD-CDs) which can respond to ClO – and AA rapidly, reversibly, and dynamically by fluorescence and colorimetry were synthesized. In the fluorescence manner, the constructed nanosensor possessed high selectivity toward ClO – in the range of 0.1–100 μM with a detection limit of 83 nM, and can be selectively recovered by AA. It endows this sensor with good capacity as a fluorescent probe for dynamic detection of ClO – and AA in living cells, which can be monitored by a fluorescence microscope. In the colorimetric manner, ClO – and AA can be detected by UV–vis in the range of 5–200 μM and 1–30 μM, respectively. The concentrations of ClO – and AA in humor can be…

Fluoride ion (F – ) is one of the most harmful elements in drinking water. Over-intake of F – can result in dental fluorosis, kidney failure, or DNA damage. Therefore, developing affordable, equipment-free, and reliable methods for F – detection is an important goal. In this work, a series of mixed lanthanide metal–organic frameworks were synthesized using a triazine-based planar ligand, 4,4′,4″- s -triazine-2,4,6-triyltribenzoate (TATB) and mixed lanthanide ions (Tb 3+ and Eu 3+ ). The luminescent color of the Tb/Eu(TATB) can be finely modulated by changing the Tb 3+ /Eu 3+ ratio in the synthesis procedure. Benefiting from the unique host–guest interaction (e.g., Lewis acid–base interaction), between F – and MOF host, a highly selective, sensitive, and reliable fluoride sensor was then developed. Moreover, visual detection of F – was achieved with a smartphone by identifying the RGB value. Drinking water samples were analyzed for F –, and the results obtained by our ratiometric luminescent method were consistent with those by ion chromatographic strategy. This easy-to-use sensor…

It has been almost 30 years since the invention of Systematic Evolution of Ligands by Exponential Enrichment (SELEX) methodology and the description of the first aptamers. In retrospect over the past 30 years, advances in aptamer development and application have demonstrated that aptamers are potentially useful reagents that can be employed in diverse areas within analytical chemistry, biotechnology, biomedicine, and molecular biology. While often touted as artificial antibodies with an ability to be selected for any target, aptamer development, unfortunately, lags behind development of analytical methodologies that employ aptamers, hindering deeper integration into the application of analytical tool development. This perspective covers recent advances in SELEX methodology for improving efficiency of the SELEX procedure and enhancing affinity and specificity of the selected aptamers, what we view as a critical barrier in the future role of aptamers in analytical chemistry. We discuss postselection modifications that can be used for enhancing performance of the selected aptamers in…

Herein, we described a novel plasmonic CRISPR Cas12a assay for the visual, colorimetric detection of grapevine viral infections. Our assay generates rapid and specific colorimetric signals for nucleic acid amplicons by combining the unique target-induced incriminate single-stranded DNase activity of Cas12a with plasmon coupling of DNA functionalized gold nanoparticles. The practical applicability of our plasmonic assay was successfully demonstrated through the detection of emerging red-blotch viral infections in grapevine samples collected from commercial vineyards.

Untargeted metabolomic measurements using mass spectrometry are a powerful tool for uncovering new small molecules with environmental and biological importance. The small molecule identification step, however, still remains an enormous challenge due to fragmentation difficulties or unspecific fragment ion information. Current methods to address this challenge are often dependent on databases or require the use of nuclear magnetic resonance (NMR), which have their own difficulties. The use of the gas-phase collision cross section (CCS) values obtained from ion mobility spectrometry (IMS) measurements were recently demonstrated to reduce the number of false positive metabolite identifications. While promising, the amount of empirical CCS information currently available is limited, thus predictive CCS methods need to be developed. In this article, we expand upon current experimental IMS capabilities by predicting the CCS values using a deep learning algorithm. We successfully developed and trained a prediction model for CCS values requiring only information about a compound's SMILES…

We have proposed a dual-quenching electrochemiluminescence (ECL) strategy which is based on tris(2,2′-bipyridyl)ruthenium(II) [Ru(bpy) 3 2+ ] as chromophores caged in three-dimensional (3D) zinc oxalate metal–organic frameworks [Ru(bpy) 3 2+ /zinc oxalate MOFs] for ultrasensitive detection of amyloid-β (Aβ). The three-dimensional chromophore connectivity in zinc oxalate MOFs provided a network for rapid excited-state energy transfer migration among Ru(bpy) 3 2+ units which shielded the chromophores from solvent molecules and led to a high-energy Ru emission efficiency. In addition, we found that both Au nanoparticles and NiFe-based nanocube MOFs could contribute to the reduction of the ECL intensity of the chromophore. The ECL emission spectra of 3D Ru(bpy) 3 2+ /zinc oxalate MOFs overlapped appropriately with the ultraviolet–visible (UV–vis) absorption spectra of Au@NiFe MOFs composites, which could trigger the resonance energy transfer (RET) behavior between Ru(bpy) 3 2+ /zinc oxalate MOFs (donor) and Au@NiFe MOFs (acceptor), achieving the dual-quenching effect of Ru(bpy) 3 2+…

Emerging nanomaterials such as nanozymes have recently been applied for the immunoassay-based detection of biomarkers. However, the inferior catalytic activity and low water solubility of nanozymes remain as the major limitations compared to natural enzymes. To overcome these limitations, we successfully synthesized a superior nanozyme with a structure of enriched 2D catalytic interface, namely Nanozyme Nest, which was composed of Fe-based metal–organic frameworks (Fe-MOF) and graphene oxide (GO). Then, we applied it in an ultrasensitive enzyme-linked immunosorbent assay (ELISA) for the detection of benzo[ a ]pyrene-7,8-diol 9,10-epoxide–DNA adduct (BPDE–DNA), which is a metabolite of benzo[ a ]pyrene (BP) and used as a typical biomarker of woodsmoke exposure in human blood. The Nanozyme Nest features amplified peroxidase-like catalytic ability from graphene and Fe-MOF due to their large surface area and abundant active sites. By using the proposed Nanozyme Nest-based ultrasensitive ELISA, the BPDE–DNA could be detected at a level as low as 0.268 ng/mL, and the obtained sensitivity…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTMultiplexed Immunosensors and ImmunoarraysAbby JonesAbby JonesDepartment of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United StatesMore by Abby JonesView Biography, Lasangi DhanapalaLasangi DhanapalaDepartment of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United StatesMore by Lasangi DhanapalaView Biography, Rumasha N. T. KankanamageRumasha N. T. KankanamageDepartment of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United StatesMore by Rumasha N. T. KankanamageView Biography, Challa V. KumarChalla V. KumarDepartment of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06269, United StatesInstitute of Materials Science, University of Connecticut, 97 North Eagleville Road, Storrs, Connecticut 06269, United StatesMore by Challa V. KumarView Biographyhttp://orcid.org/0000-0002-4396-8738, and James F. Rusling*James F. RuslingDepartment of Chemistry, University of…

Exosomes are membrane-enclosed phospholipid extracellular vesicles. In spite of their great promise as noninvasive biomarkers for cancer diagnosis, sensitive detection of exosomes is still challenging. Herein, the detection of exosomes was changed to the detection of DNA after recognition of exosomes with its aptamers. CD63 aptamer and EpCAM aptamer were used for the detection of MCF-7 cell-secreted exosome. The recognition process was amplified through the movements of a three-dimensional DNA walker. And then, Exonuclease III- assisted electrochemical ratiometric sensor was applied for further signal amplification. Under optimal conditions, the detection limit of 1.3 × 10 4 particles/mL was obtained with excellent selectivity. Furthermore, clinical application test for the detection of exosomes in human serum was also verified.

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTRecent Progress in Fast Sample Preparation TechniquesLing XiaLing XiaSchool of Chemistry, Sun Yat-sen University, Guangzhou 510275, ChinaMore by Ling XiaView Biography, Jiani YangJiani YangSchool of Chemistry, Sun Yat-sen University, Guangzhou 510275, ChinaMore by Jiani YangView Biography, Rihui SuRihui SuSchool of Chemistry, Sun Yat-sen University, Guangzhou 510275, ChinaMore by Rihui SuView Biography, Wanjun ZhouWanjun ZhouSchool of Chemistry, Sun Yat-sen University, Guangzhou 510275, ChinaMore by Wanjun ZhouView Biography, Yanshu ZhangYanshu ZhangSchool of Chemistry, Sun Yat-sen University, Guangzhou 510275, ChinaMore by Yanshu ZhangView Biography, Yanhui ZhongYanhui ZhongSchool of Chemistry, Sun Yat-sen University, Guangzhou 510275, ChinaMore by Yanhui ZhongView Biography, Simin HuangSimin HuangSchool of Chemistry, Sun Yat-sen University, Guangzhou 510275, ChinaMore by Simin HuangView Biography, Yanlong ChenYanlong ChenSchool of Chemistry, Sun Yat-sen University, Guangzhou 510275, ChinaMore by Yanlong ChenView Biography, and Gongke…

Electrochemiluminescence (ECL)-functionalized metal–organic frameworks (MOFs) have attracted increasing attention in biosensing in virtue of their diverse and tunable optical properties. A famous ECL luminophore, carboxyl-rich tris(4,4′-dicarboxylic acid-2,2′-bipyridyl) ruthenium(II) (Ru(dcbpy) 3 2+ ), possesses the characteristics of good water solubility and excellent ECL performance and also has the potential to be the organic ligand of metal–organic frameworks. Herein, functionalized MOF nanosheets (RuMOFNSs) containing plenty of Ru(dcbpy) 3 2+ in the frameworks were synthesized in aqueous solution by a simple one-pot method. In this protocol, Ru(dcbpy) 3 2+ acted as organic ligand to coordinate with Zn 2+ originated from Zn(NO 3 ) 2, and polyvinylpyrrolidone (PVP) was used as structure-directing agent to control the formation of sheetlike structure. For practical application, a “signal-on” ECL immunosensor was designed for cardiac troponin I (cTnI) detection by employing RuMOFNSs as ECL probe. The immunosensor exhibited high sensitivity and excellent selectivity for cTnI…

The precise monitoring of H 2 S has aroused immense research interest in the biological and biomedical fields since it is exposed as a third endogenous gasotransmitter. Hence, there is an urgent requisite to explore an ultrasensitive and economical H 2 S detection system. Herein, we report a simple strategy to configure an extremely sensitive electrochemical sensor with a 2D nanosheet-shaped layered double hydroxide (LDH) wrapped carbon nanotubes (CNTs) nanohybrid (CNTs@LDH), where a series of CNTs@CuMn-LDH nanohybrids with varied amounts of LDH nanosheets grafted on a conductive CNTs backbone has been synthesized via a facile coprecipitation approach. Taking advantage of the unique core–shell structure, the integrated electrochemically active CuMn-LDH nanosheets on the conductive CNTs scaffold, the maximum interfacial collaboration, and the superior specific surface area with a plethora of surface active sites and ultrathin LDH layers, the as-prepared CNTs@CuMn-LDH nanoarchitectures have exhibited superb electrocatalytic activity toward H 2 S oxidation. Under the optimum…

Herein, we synthesized bifunctional magnetic fluorescent beads (MFBs) with a distinct core/shell structure by encapsulating octadecylamine-coated CdSe/ZnS QDs (OC-QDs) and oleic acid-modified iron oxide nanoparticles (OA-IONPs) into two polymer matrixes with different hydrophobic properties. The OC-QDs and OA-IONPs were mainly distributed in the outer layer of MFBs. The resultant MFBs displayed ca. 226-fold stronger fluorescence emission relative to the corresponding OC-QDs and retained ca. 45.4% of the saturation magnetization of the OA-IONPs. The MFBs were used to purify and enrich aflatoxin B 1 (AFB 1 ) from dark soy sauce and then utilized as a fluorescent reporter of immunochromatographic assay (ICA) for the sensitive detection of AFB 1 . Under the optimal detection conditions, the MFB-based ICA (MFB-ICA) displayed a dynamic linear detection of AFB 1 in sauce extract over the range of 5–150 pg/mL with a half maximal inhibitory concentration of 27 ± 3 pg/mL ( n = 3). The detection limits for AFB 1 in sauce extract and real dark soy sauce were 3 and 51 pg/mL, respectively, which…

Ambient ionization mass spectrometry (AIMS) has grown into a group of emerging analytical techniques that allow rapid, real-time, high-throughput, in situ, and in vivo analysis in many scientific fields including biomedicine, pharmaceuticals, and forensic sciences. While dozens of AIMS techniques have been introduced over the past two decades, their broad commercial and industrial use is still restricted by multiple challenges. In this Perspective, we discuss the most relevant technical challenges facing AIMS, i.e., reproducibility, quantitative ability, molecular coverage, sensitivity, and data complexity, and scientists' recent attempts to overcome these hurdles. Furthermore, we present future directions of AIMS from our perspective, including the necessity that efforts should be made to unravel blind biomolecules in routine analysis, the construction of a data depository for AIMS users, the full automation of pipelines for prospect integration in a robotic laboratory, the movement toward on-site tests, and the expansion of outreach to motivate government officials in…

Carbon dots (CDs) are emerging as powerful tools for biosensing and bioimaging because of their intrinsic properties such as abundant precursors, facile synthesis, high biocompatibility, low cost, and particularly robust tunability and stability. In this work, a new type of CDs was prepared from m -phenylenediamine and folic acid by hydrothermal method. Interestingly, the as-prepared CDs show blue emission in non-hydrogen-bonding solution, whereas robust green emission in hydrogen-bonding solution. Based on this phenomenon, a novel fluorescence sensing mechanism named as hydrogen-bonding-induced emission (HBIE) was proposed. The HBIE-CDs have large Stokes shift (141 nm) in water, good biocompatibility, and ultrasmall size, which facilitates their translocation into living cells. Very importantly, the as-prepared HBIE-CDs show strong affinity toward nucleic acid without interference from other biological species. After binding with DNA/RNA through hydrogen bond, as high as 6-fold green fluorescence enhancement of HBIE-CDs was observed. Since the nucleus is rich in DNA/RNA, these…

Abstract Herein, the reproducibility and a double validation of on-body measurements provided by new wearable potentiometric ion sensors (WPISs) is presented. Sweat collected during sport practice was first analyzed using the developed device, the pH-meter, and ion chromatography (IC) prior to on-body measurements (off-site validation). Subsequently, the accuracy of on-body measurements accomplished by the WPISs was evaluated by comparison with pH-meter readings and IC after collecting sweat (every 10–12.5 min) during sport practice. The developed device contains sensors for pH, Cl–, K+, and Na+ that are embedded in a flexible sampling cell for sweat analysis. The electrode array was fabricated employing MWCNTs (as an ion-to-electron transducer) and stretchable materials that have been exhaustively characterized in terms of analytical performance, presenting Nernstian slopes within the expected physiological range of each ion analyte (Cl–, 10–100 mM; K+, 10–10 mM; and Na+, 10–100 mM and pH, 4.5–7.5), drift suitable for midterm exercise practice (0.3 ± 0.2 mV h–1), fast response…

We report here a novel two-stage i-DLD sorter through coupling inertial microfluidics with deterministic lateral displacement (DLD), allowing for precise, continuous, and size-based cell separation. The first stage spiral inertial microfluidic sorter is responsible for removing the overwhelming majority of background blood cells at a high-throughput manner. The precise and flow-rate insensitive DLD sorter with triangular posts serves as the second stage sorter which further removes the residual blood cells for obtaining high-purity tumor cells. After demonstrating the conceptual design, we characterize the performances of our two-stage i-DLD sorter for the separation of differently sized particles and cells. The characterization results show that a 100% complete separation of 15 and 7 μm particles was achieved, whereas a separation efficiency of over 99.9% and a target sample purity of 93.59% was realized for the separation of differently sized cells. Finally, we successfully apply our sorter for the separation of rare tumor cells from the diluted whole blood or WBCs at good…

Human telomerase RNA (hTR), an important biomarker for cancer diagnosis, is the template for the synthesis of telomeric DNA repeats and is found to be 7-fold overexpressed in tumor cells. Herein, we present a photoelectrochemical (PEC) biosensor for hTR detection coupled with a novel amplification strategy based on cascades of catalytic hairpin assembly (CHA) and hyperbranched hybridization chain reaction (HB-HCR). At the electrode surface, thiolated hairpin 1 probes were immobilized on deposited CdS nanoparticles via a Cd–S bond. In the presence of target hTR, a CHA reaction was triggered and the exposing of trigger1 could further initiate an HB-HCR reaction to form abundant hemin/G-quadruplex DNAzymes containing dendritic DNA structure. The DNAzymes’ catalytic precipitation of 4-chloro-1-naphthol (4-CN) by H 2 O 2 subsequently took place on the surface of the PEC electrode and efficiently suppressed the photocurrent output. Therefore, the change of photocurrent response had a positive linear relationship with logarithmic value of hTR concentration varying from 200 fM to 20.0 nM…

In this work, a simple and highly selective colorimetric method has been developed for quantifying trace-level ATP using Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs). It was discovered that Fe 3 O 4 NPs could present the dramatically enhanced catalysis once anchored with ATP-specific aptamers (Apts), which is about 6-fold larger than that of bare Fe 3 O 4 NPs. In the presence of ATP, however, the Apts would be desorbed from Fe 3 O 4 NPs due to the Apts-target binding event, leading to the decrease of catalysis rationally depending on ATP concentrations. A colorimetric strategy was thereby developed to facilitate the highly selective detection of ATP, showing the linear concentrations ranging from 0.50 to 100 μM. Subsequently, the developed ATP sensor was employed for the evaluation of ATP in blood with the analysis performances comparably better than those of the documented detection methods, showing the potential applications in the clinical laboratory for the detective diagnosis of some ATP-indicative diseases. Importantly, such a catalysis-based detection strategy should be extended to…

Methods that can detect and quantify single nucleotide variations (SNVs)/single nucleotide polymorphisms (SNPs) are greatly needed in the bioanalytical measurement of gene mutations and polymorphisms. Herein a visual and instrument-free SNV quantification platform is developed. Platinum nanoparticles tethered to magnetic beads by single-stranded DNAs are designed as quantitative readout reporters for a CRISPR-Cas12a nucleic acid detection system. The integration of platinum nanoreporter and CRISPR-Cas system with a volumetric bar-chart chip realizes the volumetric quantification of nucleic acids. This platform enables quantification of multiple cancer mutations in pure DNA samples and mock cell-free DNA samples in serum, with allelic fractions as low as 0.01%. This platform could have great potential in the quantification of SNVs/SNPs as well as other types of nucleic acid targets at the point of care.

In this work, a novel and effective ratio fluorescent porphyrin metal–organic framework (MOF) probe by encapsulating UiO-66(OH) 2 into the porphyrin MOF (PCN-224) was prepared, showing the excellent fluorescence performance in detecting Cu 2+ . In this probe, the signal from the green-emission UiO-66(OH) 2 encapsulated in PCN-224 was deemed as an effective reference, thus affording an effective built-in correction in complex environmental effects. The red-emission PCN-224 contained the active site for detecting Cu 2+ . At the same time, Cu 2+ can selectively quench the fluorescence intensity of PCN-224. The ratiometric probe therefore gave an effective and reliable Cu 2+ determination platform with an LOD value as low as 0.068 nM. This LOD result was better than the Cu 2+ concentration limitation in drinking water regulated by World Health Organization (WHO) and reported by some other methods. This provides a simple new sensor for rapidly detecting copper ions, which can be further expanded in various environmental and biological analysis tasks.

Here, we report ZIF-8-reduced graphene oxide (ZIF-8–rGO)-supported bimetallic AuPt nanoparticles (AuPtNPs) as a novel peroxidase mimic for high-sensitivity detection of H 2 O 2 in neutral solution. ZIF-8–graphene oxide (ZIF-8–GO) is first synthesized via a simple wet-chemistry process and subsequently immobilized with AuPtNPs via a reduction method. The resultant AuPt/ZIF-8–rGO shows enhanced peroxidase-like catalytic activity and it is applied for the electrochemical detection of H 2 O 2 in a wide concentration range, from 100 nM to 18 mM, with a very low detection limit of 19 nM (S/N = 3). This good electroanalytical performance of AuPt/ZIF-8–rGO is owing to the ultrasmall size and high dispersion of the AuPtNPs, the strong metal–support interaction between the AuPtNPs and ZIF-8–rGO bisupport, and the sandwich-like structure comprising porous ZIF-8 and loosely packed rGO nanosheets. The AuPt/ZIF-8–rGO is employed for the practical detection of H 2 O 2 in human serum samples with desirable properties. Therefore, the novel AuPt/ZIF-8–rGO is a promising nanozyme for various…

A novel ternary-emission fluorescence sensor was proposed by post-imprinting mixing blue-/green-/red-emission bovine hemoglobin (BHb) imprinted polymers (b-MIPs, g-MIPs, and r-MIPs) at a proper ratio and realized the multiplexed and visual detection of BHb. The three MIPs were individually embedded with blue-emission 7-hydroxycoumarin, green-emission CdTe quantum dots (QDs), and red-emission CdTe/ZnS QDs. Upon interaction with BHb within 8 min, the fluorescence of CdTe and CdTe/ZnS QDs were simultaneously turned off, whereas the 7-hydroxycoumarin turned on the fluorescence intensity. Thereupon, the ratiometric fluorescence intensity of the ternary emission linearly varied within 0.025-3 μM BHb, accompanying the profuse fluorescence color evolution from yellowish green to yellow to salmon to plum to purple to finally blue. In comparison with the dual- or single-emission sensor, the ternary-emission fluorescence MIPs sensor provided a wider color variation covering the green-red-blue window for accurate naked-eye determination of BHb, as well as a lower detection limit down to 7.8 nM…

The field of high-resolution mass spectrometry has undergone a rapid progress in the last years due to instrumental improvements leading to a higher sensitivity and selectivity of instruments. A variety of qualitative screening approaches, summarized as nontarget screening, have been introduced and have successfully extended the environmental monitoring of organic micropollutants. Several automated data processing workflows have been developed to handle the immense amount of data that are recorded in short time frames by these methods. Most data processing workflows include similar steps, but underlying algorithms and implementation of different processing steps vary. In this study the consistency of data processing with different software tools was investigated. For this purpose, the same raw data files were processed with the software packages MZmine2, enviMass, Compound Discoverer, and XCMS online and resulting feature lists were compared. Results show a low coherence between different processing tools, as overlap of features between all four programs was around 10%, and for each…

The exploration of nanomaterials with mimic enzyme activity (named nanozyme) has gained extensive attention in the fields of advanced analytical chemistry and materials science. Herein, the gold nanoparticles doped covalent organic frameworks (COFs) were prepared, which exhibited not only excellent mimic nitroreductase activity but also robust stability. By replacing the traditional natural enzyme tag in an enzyme-linked immunosorbent assay (ELISA), we employed the proposed nanozyme to label the detecting antibody. According to the catalytic properties of the nanozyme, 4-nitrothiophenol (4-NTP) was introduced as the substrate, which can be transformed to 4-aminothiophenol (4-ATP) in the presence of NaBH 4 . In a surface enhanced Raman scattering (SERS) assay, 4-ATP was capable of functioning as a powerful bridge to connect the gold nanostars (with excellent SERS performance) by both the Au–S bond and electrostatic force to further produce a Raman “hot spot”. Meanwhile, the Raman signal of 4-nitrothiophenol at 1573 cm –1 was weakened, and a new signal at 1591 cm –1 generated by 4-ATP…

ABSTRACT Cellular lipidome is highly regulated through lipogenesis, rendering diverse double-bond positional isomers (C=C isomer) of a given unsaturated lipid species. In recent years, there are increasing reports indicating the physiological roles of C=C isomer compositions associated with diseases, while the biochemistry has not been fully understood due to the challenge in characterizing lipid isomers inherent to conventional mass spectrometry-based lipidomics. To address this challenge, we reported a universal, user-friendly, derivatization-based strategy, MELDI ( m CPBA E poxidation for L ipid D ouble-bond I dentification), which enables both large-scale identification and spatial mapping of biological C=C isomers using commercial mass spectrometers without any instrument modification. With the developed liquid-chromatography mass spectrometry (LC-MS) lipidomics workflow, we elucidated more than 100 isomers among mono- and poly-unsaturated fatty acids and glycerophospholipids in both human serum, where novel isomers of low abundance were unambiguously quantified for the first…

Speeding up antibiotic susceptibility testing (AST) is urgently needed in clincial settings to guide fast and tailored antibiotic prescription before treatment. It remains a big challenge to achieve a sample-to-AST answer within a half working day directly from a clinical sample. Here we develop single-cell Raman spectroscopy coupled with heavy water labeling (Raman-D 2 O) as a rapid activity-based AST approach directly applicable for clinical urine samples. By rapidly transferring (15 min) bacteria in clinical urine for AST, the total assay time from receiving urine to binary susceptibility/resistance (S/R) readout was shortened to only 2.5 h. Moreover, by overcoming the nonsynchronous responses between microbial activity and microbial growth, together with setting a new S/R cutoff value based on relative C–D ratios, S/R of both pathogenic isolates and three clinical urines against antibiotics of different action mechanisms determined by Raman-D 2 O were all consistent with the slow standard AST assay used in clincial settings. This work promotes clinical practicability and…

Electrochemiluminescence (ECL) has emerged as one of the most important methods for in vitro diagnosis and detection, but it is still limited in sensitivity for ultrasensitive biodetections. Fast and ultrasensitive detection of biomolecules is critical, especially for the clinical detection of cardiac troponin I (cTnI) for cardiac infarction diagnosis. In this study, an effective tactic was developed to enhance ECL efficiency of the luminol system, by combined use of Co 2+ -based metal organic frameworks (MOF), zeolitic imidazolate frameworks (ZIF-67), and luminol-capped Ag nanoparticles (luminol-AgNPs). The integration leads to a pronounced ∼115-fold enhancement in luminol ECL. On the basis of this fascinating sensing platform, a robust label-free ECL immunosensor was constructed for ultrasensitive detection of cTnI, the main marker of myocardial infarction, with good stability and a detection limit as low as 0.58 fg mL –1 (S/N = 3).

A fluorescent chemosensor has been developed for discriminative detection of phosgene and a nerve agent mimic diethyl chlorophosphate (DCP), which was comprised of an anthracene-carboxyimide fluorophore and o -phenylenediamine (OPD) reaction site. Upon phosphorylation of OPD, the chemosensor displays an obvious fluorescence turn-on response toward DPC at 588 nm with instant response and a low detection limit (88 nM). By contrast, the chemosensor exhibits a colorimetric and fluorescence enhancement response at 500 nm toward phosgene with fast response (<2 min), high selectivity, and a low detection limit (72 nM). Furthermore, chemosensor-loaded test membrane was fabricated for real-time, portable and efficient discriminative detection of trace amounts of gaseous phosgene and DCP vapor with different optical responses.

Open microfluidic capillary systems are a rapidly evolving branch of microfluidics where fluids are manipulated by capillary forces in channels lacking physical walls on all sides. Typical channel geometries include grooves, rails, or beams and complex systems with multiple air-liquid interfaces. Removing channel walls allows access for retrieval (fluid sampling) and addition (pipetting reagents or adding objects like tissue scaffolds) at any point in the channel; the entire channel becomes a "device-to-world" interface, whereas such interfaces are limited to device inlets and outlets in traditional closed-channel microfluidics. Open microfluidic capillary systems are simple to fabricate and reliable to operate. Prototyping methods (e.g., 3D printing) and manufacturing methods (e.g., injection molding) can be used seamlessly, accelerating development. This Perspective highlights fundamentals of open microfluidic capillary systems including unique advantages, design considerations, fabrication methods, and analytical considerations for flow; device features that can be combined to…

Herein, a highly selective and sensitive photoelectrochemical (PEC) sensing platform was developed for vascular endothelial growth factor 165 (VEGF165) assay based on the porous Cu 2 O-CuO flower-induced photocurrent-polarity switching of the CdS quantum dots (QDs) modified indium–tin oxide (ITO) electrode. The porous Cu 2 O-CuO flower with uniform size and large surface area was successfully synthesized by taking Cu-MOF (HKUST-1) as the precursor. Through VEGF165-triggered catalytic hairpin assembly process, the porous Cu 2 O-CuO flower was introduced to the surface of the CdS QDs/ITO electrode, resulting in the switching of the photocurrent polarity from anodic current to cathodic current. Based on the uniform particle size, high specific surface area, good photoelectric conversion efficiency, and photocurrent polarity switching ability of porous Cu 2 O-CuO flower, the proposed sensing platform showed excellent assay performance for VEGF165 with a linear response range from 1 to 3000 fM, a detection limit of 0.3 fM, and high selectivity. By changing the specific aptamer, the…

Exosomes are small membrane-bound nanovesicles with a size of 50-150 nm which contain many functional biomolecules, such as nucleic acids and proteins. Due to their high homology with parental generation, they are of great significance in clinical diagnosis. At present, the quantitative detection of low concentrations of cancer-derived exosomes present in biofluids is still a great challenge. In this study, we develop an electrical and label-free method to directly detect exosomes with high sensitivity based on a reduced graphene oxide (RGO) field effect transistor (FET) biosensor. An RGO FET biosensor modified with specific antibody CD63 in the sensing area was fabricated and was used for electrical and label-free quantification of exosomes. The method achieved a low limit of detection down to 33 particles/μL, which is lower than that of many other available methods. In addition, the FET biosensor was employed to detect exosomes in clinical serum samples, showing significant differences in detecting healthy people and prostate cancer (PCa) patients. Different from other…

ABSTRACT We present a cross-linking/mass spectrometry (XLMS) workflow for performing proteome-wide cross-linking analyses within one week. The workflow is based on the commercially available MS-cleavable cross-linker disuccinimidyl dibutyric urea (DSBU) and can be employed by every lab having access to a mass spectrometer with tandem MS capabilities. We provide an updated version 2.0 of the freeware software tool MeroX, available at www.StavroX.com , that allows conducting fully automated and reliable studies delivering insights into protein-protein interaction networks and protein conformations at the proteome level. We exemplify our optimized workflow for mapping protein-protein interaction networks in Drosophila melanogaster embryos on a system-wide level. From cross-linked Drosophila embryo extracts, we detected 18,037 cross-link spectrum matches corresponding to 5,129 unique cross-linked residues in biological triplicate experiments at 5% FDR (3,098 at 1% FDR). Among these, 1,237 interprotein cross-linking sites were identified that contain valuable information on…

Following the expiration of the patents on fused-filament-fabrication (FFF), the availability and uses of this 3D-printing technology have exploded. Several recent reports describe how conductive composites can be used with FFF printers to generate 3D-printed electrodes (3DEs) for energy storage and electrochemical analysis. As printed materials, these electrodes have very high impedance values because of the high content of insulating thermoplastic required for FFF printers. To overcome this challenge, deposition of metals or activation with harsh chemicals has previously been employed. Here, a benign postprinting process was developed using the electrolysis of water to selectively remove the insulating thermoplastic (polylactic acid) via saponification. Optimization of the hydroxide-treatment process was found to reduce the impedance of 3DEs by 3 orders of magnitude in filaments from two manufacturers. This electrolysis-activation strategy offers a safe, accessible, and affordable means for improving the electrochemical performance of 3DEs. Here, the ability of these modified 3DEs…

Chemical isotope labeling (CIL) liquid chromatography mass spectrometry (LC-MS) is a powerful technique for in-depth metabolome analysis with high quantification accuracy. Unlike conventional LC-MS, it analyzes chemical-group-based submetabolomes and uses the combined results to represent the whole metabolome. Due to analysis time and cost constraint, not all submetabolomes can be profiled and thus knowledge of chemical group classification is important in guiding submetabolome selection. Herein we report a study of determining the distribution of functional groups of compounds in a database and then examine how well we can experimentally analyze the major chemical groups in two representative samples (i.e., human plasma and yeast). We developed a computer algorithm to classify chemical structures according to their functional groups. After removing lipids which are targeted molecules in lipidomic analysis, inorganic species and other molecules that are unique to drug, food, plant, and environmental origins, five groups (i.e., amine, phenol, hydroxyl, carboxyl, and carbonyl) are…

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTRecent Advances in Glycoproteomic Analysis by Mass SpectrometrySuttipong SuttapitugsakulSuttipong SuttapitugsakulSchool of Chemistry and Biochemistry and the Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, United StatesMore by Suttipong SuttapitugsakulView Biography, Fangxu SunFangxu SunSchool of Chemistry and Biochemistry and the Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, United StatesMore by Fangxu SunView Biography, and Ronghu Wu*Ronghu WuSchool of Chemistry and Biochemistry and the Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, United States*E-mail: [email protected]. Phone: 404-3851515. Fax: 404-894-7452.More by Ronghu WuView Biographyhttp://orcid.org/0000-0001-9493-9462Cite this: Anal. Chem. 2020, 92, 1, 267–291Publication Date (Web):October 18, 2019Publication History Published online18 October 2019Published inissue 7…

Mycotoxins posit serious threats to human and animal health, and numerous efforts have been performed to detect the multiple toxins by a single diagnostic approach. To best of our knowledge, for the first time, we synthesized an aptamer induced “turn on” fluorescence resonance energy transfer (FRET) biosensor using dual-color gold nanoclusters (AuNCs), l -proline, and BSA synthesized AuNCs (Lp-AuNCs and BSA-AuNCs), with WS 2 nanosheet for simultaneous recognition of aflatoxinB 1 (AFB 1 ) and zearalenone (ZEN) by single excitation. Here, AFB 1 aptamer stabilized blue-emitting AuNCs (AFB 1 -apt-Lp-AuNCs) (at 442 nm) and ZEN aptamer functionalized with red-colored AuNCs (ZEN-apt-BSA-AuNCs) (at 650 nm) were employed as an energy donor and WS 2 nanosheet as a fluorescence quencher. With the addition of AFB 1 and ZEN, the change in fluorescence intensity (F.I) was recorded at 442 and 650 nm and can be used for simultaneous recognition with a detection limit of 0.34 pg mL –1 ( R 2 = 0.9931) and 0.53 pg mL –1 ( R 2 = 0.9934), respectively. Most importantly, the semiquantitative…

The number of publications in the field of chemical cross-linking combined with mass spectrometry (XL-MS) to derive constraints for protein three-dimensional structure modeling and to probe protein-protein interactions has increased during the last years. As the technique is now becoming routine for in vitro and in vivo applications in proteomics and structural biology there is a pressing need to define protocols as well as data analysis and reporting formats. Such consensus formats should become accepted in the field and be shown to lead to reproducible results. This first, community-based harmonization study on XL-MS is based on the results of 32 groups participating worldwide. The aim of this paper is to summarize the status quo of XL-MS and to compare and evaluate existing cross-linking strategies. Our study therefore builds the framework for establishing best practice guidelines to conduct cross-linking experiments, perform data analysis, and define reporting formats with the ultimate goal of assisting scientists to generate accurate and reproducible XL-MS results.

A complicated relationship between the active small molecules exists in cells. On the organelle level, active small molecules also play an important role in the maintenance of organelle functions and roles. To investigate the relationship of biomolecules in subcellular, it is necessary and critical to develop molecular tools that can track two kinds of associated biomolecules within organelles with multiple fluorescence signals. However, this is still an unmet challenge up to date. Herein, we present the first single-fluorescent probe ( Lyso-HA-HS ) that can detect oxidative (HOCl) and reductive (H 2 S) substances within an organelle (lysosomes) with multiresponse signals. The reactions of the new probe with H 2 S and HOCl simultaneously result in the blue and red channels emissions, respectively, providing different signal responses to the oxidative and reductive substances in the cellular lysosomes. Using a single fluorescent probe, we first achieved dual-channel imaging of the endogenous hypochlorous acid and hydrogen sulfide, respectively, in the lysosomes in the living cells.…

The rapid, convenient, and selective assaying of clinical targets directly in complex biological media brings with it the potential to revolutionize diagnostics. One major hurdle to impact is retention of selectivity and a tight control of nonspecific surface interactions or biofouling. We report herein, the construction of an antifouling interface through the covalent attachment of designed branched zwitterionic peptides onto electrodeposited polyaniline film. The antifouling capability of the designed branched peptide significantly outperforms that of the commonly used PEG and linear peptides. The interfaces modified with branched peptides are exceptionally effective in reducing a nonspecific protein and cell adsorption, as verified by electrochemical and fluorescent characterization. The derived sensors with mucin1 protein (MUC1) aptamer as the recognition element detect MUC1-positive MCF-7 breast cancer cells in human serum with high sensitivity and selectivity. The linear response range of the cytosensor for the MCF-7 cell is from 50 to 10 6 cells/mL, with a limit of detection…

Fourier transform-infrared spectroscopy (FT-IR) represents an attractive molecular diagnostic modality for translation to the clinic, where comprehensive chemical profiling of biological samples may revolutionize a myriad of pathways in clinical settings. Principally, FT-IR provides a rapid, cost-effective platform to obtain a molecular fingerprint of clinical samples based on vibrational transitions of chemical bonds upon interaction with infrared light. To date, considerable research activities have demonstrated competitive to superior performance of FT-IR strategies in comparison to conventional techniques, with particular promise for earlier, accessible disease diagnostics, thereby improving patient outcomes. However, amidst the changing healthcare landscape in times of aging populations and increased prevalence of cancer and chronic disease, routine adoption of FT-IR within clinical laboratories has remained elusive. Hence, this perspective shall outline the significant clinical potential of FT-IR diagnostics and subsequently address current barriers to translation from the…

The detection of hydroxyl radical (·OH) in vivo faces challenges as ·OH has short lifetime and low concentration in the body. Fluorescence imaging within the second near-infrared window (NIR-II, 1000–1700 nm) is a promising approach to in vivo organ and tissue imaging, but ·OH fluorescent probes emitting at this region have not been reported up to now because of the difficulty of probe design. Herein, we report the strategy to fabricate the first NIR-II probe for ·OH by directly breaking/recovering the conjugated system and rigid planar structure of an organic fluorophore, which could regulate the fluorescence intensity regardless of emission wavelength. This activable probe, Hydro-1080, emitted in 1000–1400 nm after responding to ·OH. Hydro-1080 exhibited excellent sensitivity (LOD = 0.5 nM) and selectivity to ·OH. It was able to track subtle variation of [·OH] in liver induced by external stimuli and offered clear images with high contrast. This work also indicates that this simple and straightforward strategy can be extended to develop NIR-II fluorescent probes efficiently.

Simultaneous detection of large viruses has been a great obstacle in the field of molecular imprinting. In this work, for the first time, a multifunctional molecularly imprinted sensor for single or simultaneous determination of hepatitis A virus (HAV) and hepatitis B virus (HBV) is provided. Visual detection was realized due to the color of green and red quantum dots that varied with the concentration of the target substance. The combination of hydrophilic monomers and metal chelation reduced the nonspecific binding and enhanced the specificity of adsorption. As a result, satisfactory selectivity and sensitivity were obtained for the detection of the two viruses, with imprinting factors of 3.70 and 3.35 for HAV and HBV, and limits of detection of 3.4 and 5.3 pmol/L, respectively, that were achieved within 20 min. The excellent recoveries during simultaneous detection and single detection modes indicate the prominent ability of the proposed sensor to detect HAV and HBV in human serum and the potential ability to simultaneously detect multiple viruses in real applications.

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTEmerging Extraction Strategies in Analytical ChemistryFrederik A. HansenFrederik A. HansenDepartment of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, 0316 Oslo, NorwayMore by Frederik A. HansenView Biographyhttp://orcid.org/0000-0002-1666-0447 and Stig Pedersen-Bjergaard*Stig Pedersen-BjergaardDepartment of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, 0316 Oslo, NorwayDepartment of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark*E-mail: [email protected]. Phone: +47-22856576.More by Stig Pedersen-BjergaardView Biographyhttp://orcid.org/0000-0002-1666-8043Cite this: Anal. Chem. 2020, 92, 1, 2–15Publication Date (Web):October 18, 2019Publication History Published online18 October 2019Published inissue 7 January 2020https://pubs.acs.org/doi/10.1021/acs.analchem.9b04677https://doi.org/10.1021/acs.analchem.9b04677review-articleACS PublicationsCopyright © 2019 American Chemical SocietyRequest reuse permissionsArticle Views5213Altmetric-Citations83LEARN…

Ion mobility-mass spectrometry (IM-MS) has become an important addition to the structural biology toolbox, but separating closely related protein conformations remain challenging. Collision-induced unfolding (CIU) has emerged as a valuable technique for distinguishing iso-cross-sectional protein and protein complex ions through their distinct unfolding pathways in the gas phase. The speed and sensitivity of CIU analyses, coupled with their information-rich data sets, have resulted in the rapid growth of CIU for applications, ranging from the structural assessment of protein complexes to the characterization of biotherapeutics. This growth has occurred despite a lag in the capabilities of informatics tools available to process the complex data sets generated by CIU experiments, resulting in laborious manual analysis remaining commonplace. Here, we present CIUSuite 2, a software suite designed to enable robust, automated analysis of CIU data across the complete range of current CIU applications and to support the implementation of CIU as a true high-throughput technique. CIUSuite 2…