37,360 results match your criteria Analytical chemistry[Journal]


Challenging a preconception: Optoacoustic spectrum differs from the absorption spectrum of proteins and dyes for molecular imaging.

Anal Chem 2020 Jul 8. Epub 2020 Jul 8.

Optoacoustic (photoacoustic) imaging has seen marked advances in detection and data analysis, but there is less progress in understanding the photophysics of common optoacoustic contrast agents. This gap blocks the development of novel agents and the accurate analysis and interpretation of multispectral optoacoustic images. To close it, we developed a multi-modal laser spectrometer (MLS) to enable the simultaneous measurement of optoacoustic, absorbance, and fluorescence spectra. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01902DOI Listing

Increasing the coverage of a mass spectral library of milk oligosaccharides using a hybrid-search-based bootstrapping method and milks from a wide variety of mammals.

Anal Chem 2020 Jul 8. Epub 2020 Jul 8.

This study significantly expands both the scope and method of identification for construction of a previously reported tandem mass spectral library of 74 human milk oligosaccharides (HMOs) derived from results of combined LC-MS/MS experiments and comprehensive structural analysis of HMOs. In the present work, a hybrid search 'bootstrap' identification method was employed that substantially broadens the coverage of milk oligosaccharides and thereby increase utility use of a spectrum library-based method for the rapid tentative identification of all distinguishable glycans in milk. This involved hybrid searching of the previous library, which was itself constructed using the hybrid search of oligosaccharide spectra in the NIST 17 Tandem MS Library. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00342DOI Listing

In situ Quantitatively Observing Hygroscopic Growth of Single Nanoparticle Aerosol by Surface Plasmon Resonance Microscope.

Anal Chem 2020 Jul 8. Epub 2020 Jul 8.

Aerosol particles hygroscopicity is an important factor in visibility reduction, cloud formation, radiation forcing and the global climate. The high number concentration of nanoparticles (defined as particles with diameters below 100 nm) means that their hygroscopic growth abilities and potential contributions to the climate and environment ar¬e significant. Therefore, a rapid and accurate in situ analysis method for single nanoparticle hygroscopic growth in an atmospheric environment is important to characterize the effects of the particle's physical and chemical properties in this process. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00431DOI Listing

An Integrated Approach for Characterizing Bispecific Antibody/Antigens Complexes and Mapping Binding Epitopes with SEC/MALS, Native Mass Spectrometry and Protein Footprinting.

Anal Chem 2020 Jul 8. Epub 2020 Jul 8.

Bispecific antibodies (BsAbs), with a unique mechanism of recognizing two different epitopes or antigens, have shown potential in various therapeutic areas. Molecular characterization of BsAbs' epitopes not only allows detailed understanding of their mechanism of actions, but also guides the design and selection of drug candidate molecules. In this study, we illustrate the practical utility of an integrated approach, including size exclusion chromatography with multi-angle light scattering and native mass spectrometry (MS), for the biophysical characterization of complex formation of a BsAb with two target antigens, cluster of differentiation 3 (CD3) and B-cell maturation antigen (BCMA). Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01876DOI Listing

Antibody-free targeted proteomics assay for absolute measurement of α-tubulin acetylation.

Anal Chem 2020 Jul 8. Epub 2020 Jul 8.

Acetylation of α-tubulin at conserved lysine 40 (K40) amino acid residue regulates microtubule dynamics and controls a wide range of cellular activities. Dysregulated microtubule dynamics characterised by differential α-tubulin acetylation is a hallmark of cancer, neurodegeneration and other complex disorders. Hence, accurate quantitation of α-tubulin acetylation is required in human disease and animal model studies. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01683DOI Listing

Automated Coupling of Nanodroplet Sample Preparation with Liquid Chromatography-Mass Spectrometry for High-Throughput Single-Cell Proteomics.

Anal Chem 2020 Jul 8. Epub 2020 Jul 8.

Single-cell proteomics can provide critical biological insight into the cellular heterogeneity that is masked by bulk-scale analysis. We have developed a nanoPOTS (nanodroplet processing in one pot for trace samples) platform and demonstrated its broad applicability for single-cell proteomics. However, because of nanoliter-scale sample volumes, the nanoPOTS platform is not compatible with automated LC-MS systems, which significantly limits sample throughput and robustness. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01551DOI Listing

Proton transfer reactions for the gas-phase separation, concentration, and identification of cardiolipins.

Anal Chem 2020 Jul 8. Epub 2020 Jul 8.

Cardiolipin (CL) analysis demands high specificity, due to the extensive diversity of CL structures, and high sensitivity, due to their low relative abundance within the lipidome. While electrospray ionization mass spectrometry (ESI-MS) is the most widely used technology in lipidomics, the potential for multiple charging presents unique challenges for CL identification and quantification. Depending on the conditions, ESI-MS of lipid extracts in negative ion mode can give rise to cardiolipins ionized as both singly and doubly deprotonated anions. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c02545DOI Listing

Solid-phase PCR-amplified DNAzyme activity for real-time FO-SPR detection of the MCR-2 gene.

Anal Chem 2020 Jul 8. Epub 2020 Jul 8.

The polymerase chain reaction (PCR) has been the gold standard molecular analysis technique for decades and has seen quite some evolution in terms of reaction components, methodology and readout mechanisms. Nucleic acid enzymes (NAzymes) have been used to further exploit the applications of PCR, but so far the work was limited to the colorimetric G-quadruplex or fluorescent substrate cleaving NAzymes. In this study, a solid-phase, fiber optic surface plasmon resonance (FO-SPR) technique is presented as an alternative read-out for PCR utilizing NAzymes. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c02241DOI Listing

A biocompatible fluorescent probe for selective detection of amyloid fibrils.

Anal Chem 2020 Jul 7. Epub 2020 Jul 7.

The misfolding and aggregation of proteins leading to amyloid formation has been linked to numerous diseases, necessitating the development of tools to monitor the fibrillation process. Here, we report an intramolecular charge transfer (ICT) dye, DMNDC, as an alternative to thioflavin-T (ThT), most commonly used for monitoring amyloid fibrils. Using insulin as a model protein, we show that DMNDC efficiently reports on the kinetics of fibril formation. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00379DOI Listing

An open space diffusive filter for simultaneous species retrieval and separation.

Anal Chem 2020 Jul 8. Epub 2020 Jul 8.

We present a novel method for the local retrieval of surface bound species and their rapid in-line separation using an open space microfluidic device. Separation can be performed in less than 30 seconds using the difference in diffusivities within parallel microfluidic flows. As a proof-of-principle, we report the rapid and efficient filtration of polystyrene beads from small molecules, and surface bound red blood cells from dimethyl sulphoxide for antigen typing. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c02176DOI Listing

3D Nanoscale Chemical Imaging of Core-Shell Microspheres via Microlensed Fiber Laser Desorption Postionization Mass Spectrometry.

Anal Chem 2020 Jul 7. Epub 2020 Jul 7.

Ministry of Education (MOE) Key Laboratory of Spectrochemical Analysis and Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University,Xiamen 361005, China.

A laser desorption postionization (LDPI) nanoscale resolution mass spectrometry imaging (MSI) technique based on a microlensed fiber is proposed for 3D imaging of microspheres which have a core-shell structure. Results show that the diameter of the sampling crater can be as small as 350 nm by introducing the desorption laser to the sample surface through the microlensed fiber. The use of laser postionization greatly solves the problem of weak signal caused by the very small sampling amount. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01434DOI Listing

A Comprehensive Targeted Metabolomic Assay for Urine Analysis.

Anal Chem 2020 Jul 7. Epub 2020 Jul 7.

Among all the human biological fluids used for disease biomarker discovery or clinical chemistry, urine stands out. It can be col-lected easily and non-invasively, it is readily available in large volumes, it is typically free from protein contamination and it is chemically complex - reflecting a wide range of physiological states and functions. However, the comprehensive metabolomic analysis of urine has been somewhat less studied compared to blood. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01682DOI Listing

Probing Microbial Extracellular Respiration Ability Using Riboflavin.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

Electrochemically active bacteria (EAB) are capable of extracellular electron transfer (EET) to insoluble metal oxides, and thus play a great role in the fields of environment, energy and geosciences. However, rapid and accurate quantification of the EET ability of EAB is still challenging. In this work, we develop a riboflavin-based fluorescent method for facile, accurate and in-situ measurement of the EET ability of EAB. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01650DOI Listing

Enabling Flow-based Kinetic Off-rate Selections using a Microfluidic Enrichment Device (MFED).

Anal Chem 2020 Jul 7. Epub 2020 Jul 7.

Modern genomic sequencing efforts are identifying potential diagnostic and therapeutic targets more rapidly than existing methods can generate the peptide- and protein-based ligands required to study them. To address this problem, we have developed a Microfluidic Enrichment Device (MFED) enabling kinetic off-rate selection without the use of exogenous competitor. We tuned the conditions of the device (bed volume, flow rate, immobilized target) such that modest, readily achievable changes in flow rates favor formation or dissociation of target-ligand complexes based on affinity. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01867DOI Listing

Single-Particle Mobility Analysis Enables Ratiometric Detection of Cancer Markers under Darkfield Tracking Microscopy.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

Here we introduced a single-particle mobility analysis based ratiometric strategy for quantitative detection of disease-related biomarkers using antibody-conjugated gold nanoparticles (AuNPs) as probes under darkfield tracking microscopy (DFTM). Based on the capability of discriminating nanoparticles with different hydrodynamic sizes and detecting the changes in hydrodynamic effect, single-particle mobility analysis enables us to determine the amount of aggregated and monodispersed nanoprobes for the sandwich-like immunoassay strategy, making it possible to quantify the biotargets by analyzing the relative changes in aggregate-to-monomer ratio of nanoprobes. By using capture antibody and detection antibody conjugated AuNPs as nanoprobes, we demonstrated ratiometric detection of carcinoembryonic antigen (CEA) over a linear dynamic range from 50 pM to 750 pM, which is competent for clinic diagnostic analysis of CEA in tumor patients. Read More

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http://dx.doi.org/10.1021/acs.analchem.9b05512DOI Listing

AFM-based High-Throughput Nanomechanical Screening of Single Extracellular Vesicles.

Anal Chem 2020 Jul 7. Epub 2020 Jul 7.

The mechanical properties of extracellular vesicles (EVs) are known to influence their biological function, in terms of e.g. cellular adhesion, endo/exocytosis, cellular uptake and mechanosensing. Read More

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http://dx.doi.org/10.1021/acs.analchem.9b05716DOI Listing

On-MALDI-target N-glycan nonreductive amination by 2-aminobenzoic acid.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

2-aminobenzoic acid (2-AA) is widely used as a labeling reagent to derivatize released N-glycans at their free reducing terminus by reductive amination. 2-AA labeled glycans have increased mass spectrometric sensitivity for their identification and enable fluorescence-chromatography based glycan quantification. Drawbacks are that the labeling process is labor intensive and time consuming. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01748DOI Listing

Proteomics Using Protease Alternatives to Trypsin Benefits from Sequential Digestion with Trypsin.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, 13355, Berlin, Germany.

Trypsin is the most used enzyme in proteomics. Nevertheless, proteases with complementary cleavage specificity have been applied in special circumstances. In this work, we analyzed the characteristics of five protease alternatives to trypsin for protein identification and sequence coverage when applied to whole cell lysates. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00478DOI Listing

A Combination of FAIMS, Protein A Depletion, and Native Digest Conditions Enables Deep Proteomic Profiling of Host Cell Proteins in Monoclonal Antibodies.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

Host cell proteins (HCPs) are residual impurities generated by the expression cell line during the production of biopharmaceuticals. Although the majority of these contaminants are removed during purification, HCPs can represent a considerable risk to the efficacy and safety of a therapeutic protein if not actively monitored. The enzyme-linked immunosorbent assay (ELISA) is commonly used throughout production to monitor HCP levels but has limited ability to identify novel HCPs or provide detailed quantification. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01175DOI Listing

Comparison of Disk and Nano-tip Electrodes for Measurement of Single-Cell Amperometry during Exocytotic Release.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

We compare single-cell amperometric measurements of exocytosis from PC12 cells between two types of elec-trodes, carbon fiber disk microelectrodes and nano-tip conical-shape carbon fiber microelectrodes. During the exocytotic process, individual exocytotic release events, measured as current spikes at the electrode offer quantitative and dynamic information about chemical release from cells. Using two electrodes gives rise to unequal distance between the fusion pore and the electrode as well as fusion pore size, which leads to differ-ent average spike shapes. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c02013DOI Listing

rPTMDetermine: A Fully Automated Methodology for Endogenous Tyrosine Nitration Validation, Site-Localization, and Beyond.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

We present herein rPTMDetermine, an adaptive and fully automated methodology for the validation of identifications of rarely occurring post-translational modifications (PTMs) using a semi-supervised approach with a linear discriminant analysis (LDA) algorithm. In addition, verification was enhanced by similarity scoring on tandem mass spectrometry (MS/MS) comparisons between modified peptides and their unmodified analogues. We have applied rPTMDetermine to (1) perform fully automated validation steps for modified peptides identified from an in silico database and (2) retrieve potential yet-to-be-identified modified peptides from raw data, but missed through conventional database search. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c02148DOI Listing

Indicator Dyes and Catalytic Nanoparticles for Irreversible Visual Hydrogen Sensing.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

Using ultraviolet-visible (UV Vis) absorption spectroscopy, we have tested the reactivity of various indicator molecules combined with catalytic bimetallic gold-palladium nanoparticles (Au-Pd NPs) in solution for irreversible, and visual response to H2 with the aim to develop the most suitable indicator/Au-Pd NP system into a thin, wearable, and visual H2 sensor for non invasive monitoring of in vivo Mg implant biodegradation in research and clinical settings with fast response time. The indicators studied were bromothymol blue, methyl red, and resazurin, and the reactions of each system with H2 in the presence of Au-Pd NPs caused visual and irreversible color changes that were concluded to proceed via redox processes. The Resazurin/Au Pd NP system was deemed best suited for our research objectives because (1) this system had the fastest color change response to H2 at levels relevant to in vivo Mg-implant biodegradation compared to the other indicator/Au-Pd NP systems tested, (2) the observed redox chemistry with H2 followed well-understood reaction pathways reported in the literature, and (3) the redox products were non toxic and appropriate for medical applications. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01769DOI Listing

HYBRIDIZATION LC-MS/MS: AN ALTERNATIVE BIOANALYTICAL METHOD FOR ANTI-SENSE OLIGONUCLEOTIDE QUANTITATION IN PLASMA AND TISSUE SAMPLES.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

Quantitative bioanalysis in plasma and tissues samples are required to study the pharmacokinetic and pharmacodynamic properties of antisense oligonucleotides (ASOs). To overcome intrinsic drawbacks in specificity, sensitivity and throughput of traditional ligand-binding assay (LBA) and LC-MS/MS methods, an alternative bioanalytical method was developed by combining oligonucleotide hybridization and LC-MS/MS technologies. Target ASOs were extracted from biological samples by hybridization with biotinylated sense-strand oligonucleotides coupled to streptavidin magnetic beads. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01382DOI Listing

On-line nano-solid phase extraction Fourier-transform ion cyclotron resonance mass spectrometry workflow to analyze small scale gradients of soil solution organic matter in the rhizosphere.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

A new method combining on-line nano-solid phase extraction coupled with Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was developed to extract and analyze organic matter (OM) from microliter volumes of salt containing soil solution samples. The system allows the reproducible analysis of only minute amounts of organic carbon (down to 10 ng C) without the need of further sample preparation. The new method was applied to unravel developing small-scale patterns of dissolved organic matter (DOM) in soil solution of a soil column experiment in which Zea mays plants were grown for three weeks. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00946DOI Listing

Chemical Class Prediction of Unknown Biomolecules Using Ion Mobility-Mass Spectrometry and Machine Learning: SIFTER.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

This work presents a machine learning algorithm referred to as the Supervised Inference of Feature Taxonomy from Ensemble Randomization (SIFTER), which supports the identification of features derived from untargeted ion mobility-mass spectrometry (IM-MS) experiments. SIFTER utilizes random forest machine learning on three analytical measurements derived from IM-MS (collision cross section, CCS), mass-to-charge (m/z), and mass defect (Δm)) to classify unknown features into a taxonomy of chemical kingdom, super class, class, and subclass. Each of these classifications is assigned a calculated probability as well as alternate classifications with associated probabilities. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c02137DOI Listing

Resolution of Isomeric Mixtures in Ion Mobility Using a Combined Demultiplexing and Peak Deconvolution Technique.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States.

A combined data acquisition and data processing strategy for improving the sensitivity and resolution of ion mobility measurements is described. This strategy is implemented on a commercially available drift tube ion mobility-mass spectrometry (IM-MS) instrument and utilizes both an existing ion multiplexing strategy to achieve up to an 8-fold gain in ion signal and a new postacquisition data reconstruction technique, termed "high resolution demultiplexing" (HRdm), to improve resolution in the ion mobility dimension. A series of isomeric mixtures were qualitatively investigated with HRdm, including biologically relevant lipids and carbohydrates, which were successfully resolved by HRdm, including two monosaccharide regioisomers which differed in drift time by only 0. Read More

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http://dx.doi.org/10.1021/acs.analchem.9b05718DOI Listing

Structural Similarity Image Analysis for Detection of Adenosine and Dopamine in Fast-Scan Cyclic Voltammetry Color Plots.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

Fast-scan cyclic voltammetry (FSCV) is widely used for in vivo detection of neurotransmitters, but identifying analytes, particularly mixtures, is difficult. Data analysis has focused on identifying dopamine from cyclic voltammograms, but it would be better to analyze all the data in the three-dimensional FSCV color plot. Here, the goal was to use image analysis-based analysis of FSCV color plots for the first time, specifically the structural similarity index (SSIM), to identify rapid neurochemical events. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01214DOI Listing

Gas-Phase Protonation Thermodynamics of Biological Lipids: Experiment, Theory, and Implications.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

Phospholipids are important to cellular function and are a vital structural component of the plasma membrane and organelle membranes. These membranes isolate the cell from its environment, allow regulation of the internal concentrations of ions and small molecules, and host diverse types of membrane proteins. It remains extremely challenging to identify specific membrane protein-lipid interactions and their relative strengths. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00613DOI Listing

Component Quantification in Solids with the Mixture Analysis Using References Method.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

Quantifying components in solid mixtures composed of the same chemical species exhibiting different physical forms represents a difficult challenge in many areas of Chemistry. The development of small-molecule active pharmaceutical ingredients (APIs) is a classic example. APIs predominantly exhibit polymorphism and the propensity to form solvates and hydrates. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01045DOI Listing

Capillary Zone Electrophoresis-Top-Down Tandem Mass Spectrometry for in-depth Characterization of Hemoglobin Proteoforms in Clinical and Veterinary Samples.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

Hemoglobin (Hb) constitutes an important protein in clinical diagnostics - both in humans and animals. Among the high number of sequence variants, some can cause severe diseases. Moreover, chemical modifications such as glycation and carbamylation serve as important biomarkers for conditions such as diabetes and kidney diseases. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01350DOI Listing

Capacitive sensing for monitoring of microfluidic protocols using nanolitre dispensing and acoustic mixing.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

The development of protocols for bio/chemical reaction requires alternate dispensing and mixing steps. Whilst most microfluidic systems use the opening of additional parts of the channel to allow the ingress of fixed volumes of fluid, this requires knowledge of the protocol before the design of the chip. Our approach of using a microfluidic valve to regulate the flow into an initially empty cavity allows for on-chip protocol development and refinement. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01906DOI Listing

Correlative hyper-spectral imaging using a dimensionality reduction based image fusion method.

Anal Chem 2020 Jul 6. Epub 2020 Jul 6.

Chemical imaging techniques are increasingly being used in combination to achieve a greater amount of understanding of a sample. This is especially true in the case of mass spectrometry imaging (MSI), where the use of different ionisation sources allows detection of different classes of molecules across a range of spatial resolutions. There has been significant recent effort in the development of data fusion algorithms which attempt to combine the benefits of multiple techniques, such that the output provides additional information that would have not been present or obvious from the individual techniques alone. Read More

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http://dx.doi.org/10.1021/acs.analchem.9b05055DOI Listing

Electrochemical Investigation of Redox Processes of Labile Cu(II)/Cu(I)-Cl Complexes by Scanning Electrochemical Microscopy.

Anal Chem 2020 Jul 5. Epub 2020 Jul 5.

The studies reported here provide detailed information of kinetics and reaction mechanism determined by the scanning electrochemical microscopy (SECM) for Cu(II)/Cu(I) redox reactions in a system with excess chloride. In positive feedback mode, the tip voltammograms obtained consist of two partially overlapping reduction waves, not one quasi-reversible process one always thought. The reduced species of CuIICl42- and [CuIICl3(H2O)]- could coexist during the timescale of SECM measurements, due to the slowness of the ligand substitution reaction of [CuIICl3(H2O)]- to CuIICl42-. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00797DOI Listing

3D-Printed Column with Porous Monolithic Packing for Online Solid-Phase Extraction of Multiple Trace Metals in Environmental Water Samples.

Anal Chem 2020 Jul 3. Epub 2020 Jul 3.

Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan, ROC.

In this study, we used a multimaterial three-dimensional printing (3DP) technology and porous composite filaments (Lay-Fomm, Gel-Lay, and Lay-Felt) to fabricate solid phase extraction (SPE) columns for the enhanced extraction of multiple metal ions. When employed as sample pretreatment devices in an automatic flow injection analysis/inductively coupled plasma mass spectrometry (ICP-MS) system, these 3D-printed SPE columns performed the near-complete extractions of Mn, Co, Ni, Cu, Zn, Cd, and Pb ions from natural water samples prior to ICP-MS determination. After optimizing the column fabrication, the extraction conditions, and the automatic analysis system, the column packed with the porous composite Lay-Fomm 40 was found to provide the highest extraction performance-the extraction efficiencies of the listed metal ions were all greater than 99. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00863DOI Listing

Recognition-Driven Remodeling of Dual-Split Aptamer Triggering in Situ Hybridization Chain Reaction for Activatable and Autonomous Identification of Cancer Cells.

Anal Chem 2020 Jul 3. Epub 2020 Jul 3.

Proximity-dependent hybridization chain reaction (HCR) has shown great potential in sensing biomolecules on cell surface. However, the requirement of simultaneously occurring two adjacent bio-events limits its application. To solve the problem, split aptamers with target binding ability was introduced to combine with split triggers for initiating HCR, thus producing a novel dual-split aptamer probe (DSAP). Read More

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http://dx.doi.org/10.1021/acs.analchem.0c02524DOI Listing

A Label-Free and Regenerable Aptasensor for Real-Time Detection of Cadmium (II) by Dual Polarization Interferometry.

Anal Chem 2020 Jul 3. Epub 2020 Jul 3.

Recently, numerous aptamer-based biosensors have been developed to detect heavy metal ions. Most of aptamer-based biosensors only can be used to get some quantitative information. The mechanism of the interaction between aptamer and metal ions, however, is rarely studied. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01710DOI Listing

Complexation with a cognate antibody fragment facilitates affinity measurements of fluorescein-linked small molecule ligands.

Anal Chem 2020 Jul 3. Epub 2020 Jul 3.

The availability of reliable methods for the characterization of the binding of small molecule ligands to protein targets is crucially im-portant for Drug Discovery. We have adapted a method, routinely used for the characterization of monoclonal antibodies (Enzyme-linked immunosorbent assay, or "ELISA"), to small molecule ligands, using fluorescein conjugates and anti-fluorescein antibodies as de-tection reagents. The new small molecule-ELISA methodology was tested using a panel of binders specific to carbonic anhydrase II, with dissociation constants ranging between 6 μM and 14 nM. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c02304DOI Listing

In-situ Monitoring of Mitochondria Regulating Cell Viability by the RNA-specific Fluorescent Photosensitizer.

Anal Chem 2020 Jul 3. Epub 2020 Jul 3.

Cell viability is greatly affected by external stimulus eliciting correlated dynamical physiological processes for cells to choose survival or death. A few fluorescent probes have been designed to detect whether the cell is in survival state or apoptotic state, but monitoring the regulation process of the cell undergoing survival to death remains a long-standing challenge. Herein, we highlight the in-situ monitor of mitochondria regulating the cell viability by the RNA-specific fluorescent photosensitizer L. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c02298DOI Listing
July 2020
5.636 Impact Factor

A multifunctional platform for the capture, release, and enumeration of circulating tumor cells based on aptamer binding, nicking endonuclease-assisted amplification, and inductively coupled plasma mass spectrometry detection.

Anal Chem 2020 Jul 2. Epub 2020 Jul 2.

Inductively coupled plasma mass spectrometry (ICP-MS) combined with element tags has been well designed and extensively applied in cell enumeration. It possesses superior quantitative capability, strong resistance to matrix interference, multiplex detection capability but destructive characteristic. Herein, we constructed an ICP-MS based multifunctional platform for capture, nondestructive enumeration and release of circulating tumor cells (CTCs). Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00276DOI Listing

Faster and more specific: ESIPT-based dyes for high-fidelity dynamic imaging of lipid droplets within cells and tissues.

Anal Chem 2020 Jul 2. Epub 2020 Jul 2.

Lipid droplets (LDs), a type of dynamic organelles residing at the centre of cellular lipid storage, have been identified to play important roles in multiple biological processes, metabolic disorders, and diseases. The highly dynamic characters of LDs were found to correspond to their physiological and pathological functions. Hence, the fluorescent probes which enable dy-namic tracking of LDs should be very helpful for better understanding the mechanisms of LDs involved biological processes and diseases. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00390DOI Listing

Microfluidic Immunoassays for Sensitive and Simultaneous Detection of IgG/IgM/Antigen of SARS-CoV-2 within 15 min.

Anal Chem 2020 Jul 2. Epub 2020 Jul 2.

The outbreak of SARS-CoV-2 is posing serious global public health problems. Facing the emergence of this pandemic, we established a portable microfluidic immunoassay system for easy-to-use, sensitive, rapid (<15 min), multiple and on-site detection of IgG/IgM/Antigen of SARS-CoV-2 simultaneously. This integrated method was successfully applied for detecting SARS-CoV-2 IgM and IgG antibodies in clinical human serum as well as SARS-CoV-2 antigen in pharyngeal swab from 26 patients with COVID-19 infection and 28 uninfected people. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01635DOI Listing

Improved annotation of untargeted metabolomics data through buffer modifications that shift adduct mass and intensity.

Anal Chem 2020 Jul 2. Epub 2020 Jul 2.

Annotation of untargeted high-resolution full-scan LC-MS metabolomics data remains challenging due to individual metabolites generating multiple LC-MS peaks arising from isotopes, adducts and fragments. Adduct annotation is a particular challenge, as the same mass difference between peaks can arise from adduct formation, fragmentation, or different biological species. To address this, here we describe a Buffer Modification Workflow (BMW), in which the same sample is run by LC-MS in both liquid chromatography solvent with 14NH3-acetate buffer, and in solvent with the buffer modified with 15NH3-formate. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00985DOI Listing

SOM-RPM for the accurate visualization of high-dimensional hyperspectral data.

Anal Chem 2020 Jul 2. Epub 2020 Jul 2.

We present an optimization of the toroidal self-organizing map (SOM) algorithm for the accurate visualization of hyperspectral data. This represents a significant advance from our previous work, in which we demonstrated the use of toroidal SOMs for the visualization of time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging data. We have previously shown that the toroidal SOM can be used, unsupervised, to produce a multicolor similarity map of the analysis area, in which pixels with similar mass spectra are assigned a similar color. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00986DOI Listing

Raman Spectroscopy to Monitor Post-translational Modifications and Degradation in Monoclonal Antibody Therapeutics.

Anal Chem 2020 Jul 2. Epub 2020 Jul 2.

Monoclonal antibodies (mAbs) represent a rapidly expanding market for biotherapeutics. Structural changes in the mAb can lead to unwanted immunogenicity, reduced efficacy and loss of material during production. The pharmaceutical sector requires new protein characterisation tools that are fast, applicable in situ and to the manufacturing process. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00627DOI Listing

In Vivo Molecular Insights into Syntrophic Geobacter Aggregates.

Anal Chem 2020 Jul 2. Epub 2020 Jul 2.

Direct interspecies electron transfer (DIET) has been considered as a novel and highly efficient strategy in both natural anaerobic envi-ronments and artificial microbial fuel cells. A syntrophic model consisting of Geobacter metallireducens and Geobacter sulfurre-ducens was studied in this work. We conducted in vivo molecular mapping of the outer surface of the syntrophic community as the interface of nutrients and energy exchange. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00653DOI Listing

Enhancing Host-Cell Protein Detection in Protein Therapeutics Using HILIC Enrichment and Proteomic Analysis.

Anal Chem 2020 Jul 2. Epub 2020 Jul 2.

Liquid chromatography-mass spectrometry (LC-MS)-based proteomics approaches have been widely used to identify residual host-cell proteins (HCPs) in support of process and product characterization for protein therapeutics. Particularly, these methods can provide a general and unbiased approach for the detection of HCPs and may generate critical information on HCPs that are outside the coverage provided by a conventional immunoassay. A significant technical hurdle for HCP analysis is the overwhelmingly large background of biotherapeutic that obscures HCP detection and quantification. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00360DOI Listing

Detection and differentiation of bacterial and fungal infection of neutrophils from peripheral blood using Raman spectroscopy.

Anal Chem 2020 Jul 2. Epub 2020 Jul 2.

Neutrophils are important cells of the innate immune system and the major leukocyte subpopulation in blood. They are responsible for recognizing and neutralizing invading pathogens, such as bacteria or fungi. For this, neutrophils are well equipped with pathogen recognizing receptors, cytokines, effector molecules and granules filled with reactive oxygen species (ROS)-producing enzymes. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c01384DOI Listing

Exosome Purification and Analysis Using a Facile Microfluidic Hydrodynamic Trapping Device.

Anal Chem 2020 Jul 2. Epub 2020 Jul 2.

Exosomes are nano-sized (30-150 nm) extracellular vesicles (EVs) secreted by various cell types. They are easily accessible in biological fluids and contain specific disease biomarkers, making them attractive for diagnosis and prognosis applications. Accurate biological characterization of exosomes is an important step towards clinical applications which require effective and precise isolation of sub-populations of exosomes. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c02006DOI Listing

Formation of Gaseous Proteins via the Ion Evaporation Model (IEM) in Electrospray Mass Spectrometry.

Anal Chem 2020 Jul 1. Epub 2020 Jul 1.

The mechanisms whereby protein ions are released into the gas phase from charged droplets during electrospray ionization (ESI) continue to be controversial. Several pathways have been proposed. For native ESI the charged residue model (CRM) is favored; it entails the liberation of proteins via solvent evaporation to dryness. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c02290DOI Listing

Metabolite Structure Assignment Using in silico NMR Techniques.

Anal Chem 2020 Jul 1. Epub 2020 Jul 1.

A major challenge for Metabolomic analysis is to obtain an unambiguous identification of the metabolites detected in a sample. Among metabolomics techniques, NMR spectroscopy is a sophisticated, powerful, and generally applicable spectroscopic tool that can be used to ascertain the correct structure of newly isolated biogenic molecules. However, accurate structure prediction using computational NMR techniques depends on how much of the relevant conformational space of a particular compound is considered. Read More

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http://dx.doi.org/10.1021/acs.analchem.0c00768DOI Listing