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    32950 results match your criteria Analytical Chemistry [Journal]

    1 OF 659

    Surface acoustic wave (SAW)-driven device for dynamic cell cultures.
    Anal Chem 2018 May 23. Epub 2018 May 23.
    In the last decades new types of cell cultures have been introduced to provide better cell survival and development, and micro/nano-environmental physico-chemical conditions aimed to mimic those present in vivo. However, despite the efforts made, the systems available to date are often difficult to replicate and use. Here, an easy-to-use surface acoustic wave (SAW)-based platform is presented for realizing dynamic cell cultures that is compatible with standard optical microscopes, incubators and cell culture dishes. Read More

    Identification of YTH Domain-Containing Proteins as the Readers for N1-Methyladenosine in RNA.
    Anal Chem 2018 May 23. Epub 2018 May 23.
    N1-methyladenosine (m1A) is an important post-transcriptional modification in RNA; however, the exact biological role of m1A remains to be determined. By employing a quantitative proteomics method, we identified multiple putative protein readers of m1A in RNA, including several YTH domain family proteins. We showed that YTHDF1-3 and YTHDC1, but not YTHDC2, could bind directly to m1A in RNA. Read More

    Quantification of Serum High Mobility Group Box-1 by Liquid Chromatography High Resolution Mass Spectrometry: Implications for its role in Immunity, Inflammation, and Cancer.
    Anal Chem 2018 May 23. Epub 2018 May 23.
    High mobility group box 1 (HMGB1), is a non-histone chromosomal protein, which can be secreted through a variety of pathways and bind to pattern recognition receptors to release pro-inflammatory cytokines. Previous studies have suggested that HMGB1 is up-regulated in numerous inflammatory diseases and that it could be a biomarker for such diseases. However, these studies used immunoassay-based methods to analyze serum HMGB1. Read More

    Entrapment of Prostate Cancer Circulating Tumor Cells with a Sequential Size-Based Microfluidic Chip.
    Anal Chem 2018 May 23. Epub 2018 May 23.
    Circulating tumor cells (CTCs) are broadly accepted as an indicator for early cancer diagnosis and disease severity. However, there is currently no reliable method available to capture and enumerate all CTCs as most systems require either an initial CTC isolation or antibody-based capture for CTC enumeration. Many size-based CTC detection and isolation microfluidic platforms were presented in the past few years. Read More

    Environmental Stability of Plasmonic Biosensors based on Natural vs. Artificial Antibody.
    Anal Chem 2018 May 23. Epub 2018 May 23.
    Plasmonic biosensors based on the refractive index sensitivity of localized surface plasmon resonance (LSPR) are considered to be highly promising for on-chip and point-of-care biodiagnostics. However, most of the current plasmonic biosensors employ natural antibodies as biorecognition elements, which are easy to lose their biorecognition ability upon exposure to environmental stressors (e.g. Read More

    Development of an Electrochemical Paper-Based Analytical Device for Trace Detection of Virus Particles.
    Anal Chem 2018 May 23. Epub 2018 May 23.
    Viral pathogens are a serious health threat around the world, particularly in resource limited settings, where current sensing approaches are often insufficient and slow, compounding the spread and burden of these pathogens. Here, we describe a la-bel-free, point-of-care approach towards detection of virus particles, based on a microfluidic paper-based analytical device with integrated microwire Au electrodes. The device is initially characterized through capturing of streptavidin modified na-noparticles by biotin-modified microwires. Read More

    Sub-ppm H2S Colorimetric Sensor: Lead Acetate Anchored Nanofibers toward Halitosis Diagnosis.
    Anal Chem 2018 May 23. Epub 2018 May 23.
    Lead(II) acetate (Pb(Ac)2) reacts with hydrogen sulfide to form colored brownish precipitates of lead sulfide. Thus far, in order to detect leakage of H2S gas in industrial sectors, Pb(Ac)2 has been used as an indicator in the form of test papers with a detection limit only as low as 5 ppm. Diagnosis of halitosis by exhaled breath needs sensors able to detect down to 1 ppm of H2S gas. Read More

    Versatile Electrochemiluminescence Assays for PEDV Antibody Based on Rolling Circle Amplification and Ru- DNA Nanotags.
    Anal Chem 2018 May 23. Epub 2018 May 23.
    The sensitive and accurate detection methods for PEDV antibody have practical significance for the prevention and treatment of PEDV. In this work, a new multiple pathways signal amplification method was proposed to construct a sensitive electroluminescence (ECL) platform for the detection of PEDV antibody. By using Au NPs modified graphene nanosheet (Au-GN) as substrate, antibody-antigen reaction as recognition unit, rolling circle amplification (RCA) for signal enhancement, and assembled cascade Ru-DNA nanotags as signal label, the proposed platform behaved good specificity and sensitivity. Read More

    Self-Assembled Chiral Gold Supramolecules with Efficient Laser Absorption for Enantiospecific Recognition of Carnitine.
    Anal Chem 2018 May 22. Epub 2018 May 22.
    Stereospecific recognition of chiral molecules is ubiquitous in chemical and biological systems, thus leading to a strong de-mand for the development of enantiomeric drugs, enantioselective sensors, and asymmetric catalysts. In this study, we demonstrate the ratio of D-Cys and L-Cys playing an important role in determining the optical properties and the structures of self-assembled Cys-Au(I) supramolecules prepared through a simple reaction of tetrachloroaurate(III) with chiral cyste-ine (Cys). The irregularly shaped -[D-Cys-Au(I)] - or -[L-Cys-Au(I)] - supramolecules with a size larger than 500 nm pos-sessing strong absorption in the near-UV region and chiroptical characteristics were only obtained from the reaction of Au(III) with D-Cys or L-Cys. Read More

    Electrochemical impedance spectroscopy for real-time detection of lipid membrane damage based on a porous self-assembly monolayer support.
    Anal Chem 2018 May 22. Epub 2018 May 22.
    Layer-by-layer dissolution and permeable pore formation are two typical membrane damage pathways, which induce membrane function disorder and result in serious disease, such as Alzheimer's disease, Keshan disease, Sickle-cell disease and so on. To effectively distinguish and sensitively monitor these two typical membrane damage pathways, a facile electrochemical impedance strategy was developed on a porous self-assembly monolayer (pSAM) supported bilayer lipid membrane (BLM). The pSAM was prepared by selectively electrochemical reductive desorption of the mercaptopropionic acid in a mixed mercaptopropionic acid/11-mercaptoundecanoic acid self-assembled monolayer, which created plenty of nanopores with tens of nanometers in diameter and several nanometers in height (defined as inner-pores). Read More

    Electrochemical Determination of TNT, DNT, RDX and HMX with Gold Nanoparticles/Poly(Carbazole-Aniline) Film-Modified Glassy Carbon Sensor Electrodes Imprinted for Molecular Recognition of Nitroaromatics and Nitramines.
    Anal Chem 2018 May 22. Epub 2018 May 22.
    Since nitroaromatic and nitramine type energetic materials, mostly arising from military activities, are persistent pollutants in soil and groundwater, on-site sensing of these hazardous chemicals has gained importance. A novel electrochemical sensor was designed for detecting nitroaromatic and nitramine type energetic materials, relying on gold nanoparticles (Au) -modified glassy carbon (GC) electrode coated with nitro-energetic memory poly(carbazole-aniline) copolymer (Cz- co-ANI) film (e.g. Read More

    A Red-emitting Fluorescent Probe for Detection of γ-Glutamyltranspeptidase and Its Application of Real-Time Imaging under Oxidative Stress in Cells and In Vivo.
    Anal Chem 2018 May 22. Epub 2018 May 22.
    γ-Glutamyltranspeptidase (GGT) plays critical roles in regulating various physiological/pathophysiological processes including the intracellular redox homeostasis. However, an effective fluorescent probe for dissecting the relationships between GGT and oxidative stress in vivo remains largely unexplored. Herein, we present a light-up fluorescent probe (DCDHF-Glu) with long wavelength emission (613 nm) for the highly sensitive and selective detection of GGT using dicyanomethylenedihydrofuran derivative as the fluorescent reporter and γ-glutamyl group as the enzyme-active trigger. Read More

    Colorimetric Readout for Potentiometric Sensors with Closed Bipolar Electrodes.
    Anal Chem 2018 May 23. Epub 2018 May 23.
    Department of Inorganic and Analytical Chemistry , University of Geneva , Quai Ernest-Ansermet 30 , 1211 Geneva 4, Switzerland.
    We present here a general strategy to translate potential change at a potentiometric probe into a tunable color readout. It is achieved with a closed bipolar electrode where the ion-selective component is confined to one end of the electrode while color is generated at the opposite pole, allowing one to physically separate the detection compartment from the sample. An electrical potential is imposed across the bipolar electrode by solution contact such that the potentiometric signal change at the sample side modulates the potential at the detection side. Read More

    Cryptophane nanoscale assemblies expand 129Xe NMR biosensing.
    Anal Chem 2018 May 21. Epub 2018 May 21.
    Cryptophane-based biosensors are promising agents for the ultrasensitive detection of biomedically relevant targets via 129Xe NMR. Dynamic light scattering revealed that cryptophanes form water-soluble aggregates of tens-to-hundreds of nanometers in size. Acridine orange fluorescence quenching assays allowed quantitation of aggregation state, with critical concentration rang-ing from 200 to 600 nM, depending on the cryptophane species in solution. Read More

    Stackable Lab-on-Paper Device with All-in-One Au Electrode for High-Efficiency Photoelectrochemical Cyto-Sensing.
    Anal Chem 2018 May 21. Epub 2018 May 21.
    Highly conductive, robust, and multifunctional integrated paper-supported electrodes are requisite to fulfill the promise of paper-based analytical application. Herein, an all-in-one Au electrode comprising of detection zone, waterproof electronic bridge, and signal output contactor was engineered via combining the double-sided growth method with the secondary wax-printing. Benefiting from the strongly omnidirectional conductivity and desirably mechanical robustness of the as-prepared electrode, a stackable lab-on-paper cyto-device integrated with high-efficiency photoelectrochemical strategy was developed for the MCF-7 cells assay. Read More

    Electrified soft interface as a selective sensor for cocaine detection in street samples.
    Anal Chem 2018 May 21. Epub 2018 May 21.
    A straightforward, direct and selective method is presented for electrochemical cocaine identification in street samples. The sensing mechanism is based on a simple ion transfer reaction across the polarized liquid-liquid interface. The interfacial behavior of a number of cutting agents is also reported. Read More

    Fused silica micro-capillaries used for a simple miniaturization of the electrified liquid - liquid interface.
    Anal Chem 2018 May 21. Epub 2018 May 21.
    Short pieces of fused silica capillary tubing were used to support an electrified liquid - liquid interface. A methyl deactivated silica capillary having a diameter of 25 µm was filled with 1,2-dichloroethane solution and served as the organic part of the liquid - liquid interface. A non-deactivated fused silica capillary having a diameter of 5, 10 or 25 µm were filled with an aqueous HCl solution and served as the aqueous part of the electrochemical cell. Read More

    Instrumentation for xPCR incorporating qPCR and HRMA.
    Anal Chem 2018 May 21. Epub 2018 May 21.
    A microfluidic PCR device was developed that enables DNA amplification at speeds as fast as 2 seconds/cycle, with concurrent detection and amplification. Two targets were amplified from human genomic DNA. By observing the fluorescence emitted by a DNA dye while the sample is amplified, it is possible to obtain both qPCR and spatial melting information about the amplified product. Read More

    Evaluating Drug-induced Liver Injury and Its Remission via Discrimination and Imaging of HClO and H2S with a Two-photon Fluorescent Probe.
    Anal Chem 2018 May 21. Epub 2018 May 21.
    Drug-induced liver injury (DILI) has aroused wide concern. Finding new markers or indicators as well as detoxification molecules for DILI are of great significance and good application prospect, which can help develop effective preclinical screening methodology and corresponding treatment protocols. Herein, in this paper, DILI caused by antidepressant drugs of duloxetine and fluoxetine and its remission were evaluated by a two-photon fluorescent probe, RPC-1, through discriminating and imaging HClO and H2S simultaneously. Read More

    Gas Analysis by Electron Ionization Combined with Chemical Ionization in a Compact FT-ICR Mass Spectrometer.
    Anal Chem 2018 May 20. Epub 2018 May 20.
    In this paper, a compact Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer based on a permanent magnet is presented. This instrument has been developed for real-time analysis of gas emissions. The instrument is well suited to industrial applications or analysis of toxic and complex samples where the concentrations can vary rapidly on a wide range. Read More

    Molecularly-imprinted polymers for compound-specific isotope analysis of polar organic micropollutants in aquatic environments.
    Anal Chem 2018 May 20. Epub 2018 May 20.
    Compound-specific isotope analysis (CSIA) of polar organic micropollutants in environmental waters requires a processing of large sample volumes to obtain the required analyte masses for analysis by gas chromatography / isotope-ratio mass spectrometry (GC/IRMS). However, the accumulation of organic matter of unknown isotopic composition in standard enrichment procedures currently compromises the accurate determination of isotope ratios. We explored the use of molecularly-imprinted polymers (MIPs) for selective analyte enrichment for 13C/12C and 15N/14N ratio measurements by GC/IRMS using 1H-benzotriazole, a typical corrosion inhibitor in dishwashing detergents, as example of a widely detected polar organic micropollutant. Read More

    Hollow Micropillar Array Method for High-Capacity Drug Screening on Filter-Grown Epithelial Cells.
    Anal Chem 2018 May 19. Epub 2018 May 19.
    New high-throughput assay formats and innovative screening technologies are needed for miniaturized screens using small quantities of near-native, patient-derived cells. Here, we developed a hollow micropillar array method to screen compounds using epithelial cells cultured on a porous support, with the goal of screening thousands of compounds using a single 24-mm diameter transwell filter containing cultured cells. Test compounds (~1 nL) in an alginate hydrogel were printed by microinjection in hollow cylindrical micropillars (height 150 μm, inner diameter 100 μm) spaced 300 μm apart in a square array configuration. Read More

    Detection of Nucleic Acids in Complex Samples via Magnetic Microbead-assisted Catalyzed Hairpin Assembly and "DD-A" FRET.
    Anal Chem 2018 May 21. Epub 2018 May 21.
    Nucleic acids, as one kind of significant biomarkers, have attracted tremendous attention and exhibited immense value in fundamental studies and clinical applications. In this work, we developed a fluorescent assay for detecting nucleic acids in complex samples based on magnetic microbead (MMB)-assisted catalyzed hairpin assembly (CHA) and donor donor-acceptor fluorescence resonance energy transfer ("DD-A" FRET) signaling mechanism. Three types of DNA hairpin probes were employed in this system, including Capture, H1 (double FAM-labelled probe as FRET donor) and H2 (TAMRA-labelled probe as FRET acceptor). Read More

    Quantitative Glycomic Analysis by Mass Defect-Based Dimethyl Pyrimidinyl Ornithine (DiPyrO) Tags and High-Resolution Mass Spectrometry.
    Anal Chem 2018 May 20. Epub 2018 May 20.
    We recently developed a novel amine-reactive mass defect-based chemical tag, dimethyl pyrimidinyl ornithine (DiPyrO), for quantitative proteomic analysis at the MS1 level. In this work, we further extend the application of the DiPyrO tag, which provides amine group reactivity, optical detection capability, and improved electrospray sensitivity, to quantify N-linked glycans enzymatically released from glycoproteins in the glycosylamine form. Duplex DiPyrO tags that differ in mass by 45. Read More

    Automated 3D-Printed Microfluidic Array for Rapid Nanomaterial-enhanced Detection of Multiple Proteins.
    Anal Chem 2018 May 21. Epub 2018 May 21.
    We report here the fabrication and validation of a novel 3D printed, automated immunoarray to detect multiple proteins with ultralow detection limits. This low cost, miniature immunoarray employs electrochemiluminescent (ECL) detection measured with a CCD camera and employs touch screen control of a micropump to facilitate automated use. The miniaturized array features prefilled reservoirs to deliver sample and reagents to a paper-thin pyrolytic graphite microwell detection chip to complete sandwich immunoassays. Read More

    Double Photosystems-Based 'Z-Scheme' Photoelectrochemical Sensing Mode for Ultrasensitive Detection of Disease Biomarker Accompanying 3D DNA Walker.
    Anal Chem 2018 May 18. Epub 2018 May 18.
    A new double photosystems-based 'Z-scheme' photoelectrochemical (PEC) sensing platform is designed for ultrasensitive detection of prostate-specific antigen (PSA) by coupling with three-dimensional (3D) DNA walker. Two photosystems consist of CdS quantum dots (photosystem I; PS I) and BiVO4 photoactive materials (photosystem II; PS II), whereas gold nanoparticles (AuNPs) photodeposited on high-active {010} facets of BiVO4 are used as the electron mediators to promote electron transfer from conduction band (CB) of PS II to valence band (VB) of PS I. 3D DNA walker-based amplification strategy is carried out between hairpin DNA1 conjugated onto the AuNP, hairpin DNA2 labeled with CdS quantum dot (QD-H2) and DNA walker complementary with the PSA aptamer modified to magnetic bead (Apt-MB). Read More

    In Situ Spectroelectrochemical Monitoring of Dye Bleaching After Electrogeneration of Chlorine-Based Species. Application to Chloride Detection.
    Anal Chem 2018 May 18. Epub 2018 May 18.
    Spectroelectrochemical techniques are becoming increasingly versatile tools to solve a diverse range of analytical problems. Herein, the use of in situ real-time luminescence spectroelectrochemistry to quantify chloride ions is demonstrated. Utilizing the bleaching effect of chlorine-based electrogenerated products after chloride oxidation, it is shown that the fluorescence of the Rhodamine 6G dye decrease proportionally to the initial chloride concentration in solution. Read More

    Bioinspired Synergy Sensor Chip of Photonic Crystals-Graphene Oxide for Multiamines Recognition.
    Anal Chem 2018 May 21. Epub 2018 May 21.
    Key Laboratory of Green Printing, Institute of Chemistry , Chinese Academy of Sciences (ICCAS), Beijing Engineering Research Center of Nanomaterials for Green Printing Technology, Beijing National Laboratory for Molecular Sciences (BNLMS) , Beijing 100190 , China.
    Benefiting from the integrated functions of cilia and glomeruli in the olfactory system, animals can discriminate various odors even in hostile environments. Inspired by this synergetic system of response and signal processing units, a sensor chip of graphene oxide (GO) and photonic crystals (PCs) is fabricated. The GO aerogel functions like the olfactory cilia, which effectively captures the analytes and generates abundant sensing signals for recognition; and the PCs act as the olfactory glomeruli, whose periodic structure enables selective enhancement of the fluorescent signals to realize further signal processing. Read More

    Visualization and Semi-Quantity Study of the Distribution of Ma-jor Components in Wheat Straw in Mesoscopic Scale using FTIR Microspectroscopic Imaging.
    Anal Chem 2018 May 18. Epub 2018 May 18.
    Understanding the biochemical heterogeneity of plant tissue linked to crop straw anatomy is attractive to plant researchers and researchers in the field of biomass-refinery. This study provides an in-situ analysis and semi-quantitative, visualization distributions of major composition distribution in internodal transverse sections of wheat straw based on FTIR microspec-troscopic imaging, with a fast Non-Negativity-Constrained Least Squares (fast NNLS) fitting. The paper investigates changes in biochemical components of tissue during stages of elongation, booting, heading, flowering, grain-filling, milk-ripening, dough, and full-ripening. Read More

    Highly simple and sensitive molecular amplification-integrated fluorescence anisotropy for rapid and on-site identification of adulterated beef.
    Anal Chem 2018 May 18. Epub 2018 May 18.
    Fluorescence polarization (FP) signal is a self-referencing fluorescence signal, and it is less dependent on dye concentration and environmental interferences, which makes FP measurement a highly attractive alternative sensing technology to conventional fluorescent detection methods. Here we adopted a strategy for rapid increase of molecular weight to increase the FP signal for the detection of meat adulteration. The molecular weight of fluorescent labeled primers increased rapidly by slight pre-amplification and FP value were varied accordingly. Read More

    Nanoliter cell culture array with tunable chemical gradients.
    Anal Chem 2018 May 17. Epub 2018 May 17.
    A multitude of cell screening assays for diagnostic and research applications rely on quantitative measurements of a sample in the presence of different reagent concentrations. Standard methods rely on microtiter plates of varying well density, which provide simple and standardized sample addressability. However, testing hundreds of chemical dilutions requires complex automation, and typical well volumes of microtiter plates are incompatible with the analysis of a small number of cells. Read More

    Quantitative Surface-Enhanced Raman Spectroscopy through the Interface-Assisted Self-assembly of Three-Dimensional Silver Nanorod Substrates.
    Anal Chem 2018 May 17. Epub 2018 May 17.
    The realization of surface-enhanced Raman spectroscopy (SERS) to be a reliable quantitative analytical technique requires sensitive and reproducible enhancing substrates. Here, uniform three-dimensional (3D) Ag nanorod (AgNR) substrates with well-defined interlayer spacings are prepared through the air-liquid interface-assisted self-assembly of AgNR in a layer-by-layer manner. The correlation of the SERS performance with the 3D AgNR structures is performed by SERS mapping the substrates. Read More

    Monitoring cobalt-oxide single particle electrochemistry with sub-diffraction accuracy.
    Anal Chem 2018 May 17. Epub 2018 May 17.
    By partially overcoming the diffraction limit, super-localization techniques have extended the applicability of optical techniques down to the nanometer size-range. Herein, cobalt oxide-based nanoparticles are electrochemically grown onto carbon nanoelectrodes and their individual catalytic properties are evaluated through a combined electrochemical-optical approach. Using dark-field white light illumination, edges super-localization techniques are applied to quantify changes in particle size during elec-trochemical activation with up to 20 nm precision. Read More

    Pixel Counting of Fluorescence Spots Triggered by DNA Walkers for Ultrasensitive Quantification of Nucleic Acid.
    Anal Chem 2018 May 23. Epub 2018 May 23.
    State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing , Jiangsu 210023 , P. R. China.
    A pixel counting strategy is designed on the basis of DNA walker-triggered fluorescence spots for ultrasensitive detection of nucleic acid. The two-dimensional DNA walker was constructed by hybridization of two types of capture DNAs, which were covalently modified by click chemistry on a glass slide, and dye-labeled hairpin structure (hDNA) as track and swing strand (sDNA) as DNAzyme, respectively. Introduction of target DNA unlocked the sDNA via strand displacement to form the activated DNAzyme, and the latter cut nearby hDNA with Mn as cofactor, resulting in fluorescence recovery of dye-labeled hDNA on the substrate due to the separation from the quencher. Read More

    Detection of PCR-amplified tuberculosis DNA fragments with polyelectrolyte-modified field-effect sensors.
    Anal Chem 2018 May 17. Epub 2018 May 17.
    Field-effect-based electrolyte-insulator-semiconductor (EIS) sensors were modified with a bilayer of positively charged weak polyelectrolyte (poly(allylamine hydrochloride) (PAH)) and probe single-stranded deoxyribonucleic acid (ssDNA) and are used for the detection of target complementary deoxyribonucleic acid (cDNA) in different test solutions. The sensing mechanism is based on the detection of the intrinsic molecular charge of target cDNA molecules after the hybridization event between cDNA and immobilized probe ssDNA. The test solutions contain synthetic cDNA oligonucleotides (with a sequence of tuberculosis mycobacteria genome) or PCR-amplified DNA (which origins from a template DNA strand that has been extracted from M. Read More

    Highly Sensitive and Practical Fluorescent Sandwich ELISA for Ciguatoxins.
    Anal Chem 2018 May 17. Epub 2018 May 17.
    Ciguatera fish poisoning (CFP) caused by the consumption of fish that have accumulated ciguatoxins (CTXs) affects more than 50,000 people annually. The spread of CFP causes enormous damage to public health, fishery resources, and the economies of tropical and subtropical endemic regions. The difficulty in avoiding CFP arises from the lack of sensitive and reliable analytical methods for the detection and quantification of CTXs in contaminated fish, along with the normal appearance, smell, and taste of fish contaminated with the causative toxins. Read More

    Fluorinated DNA Micelles: Synthesis and Properties.
    Anal Chem 2018 May 24. Epub 2018 May 24.
    Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences , Aptamer Engineering Center of Hunan Province, Hunan University , Changsha , Hunan 410082 , China.
    Creating new functional building blocks that expand the versatility of nanostructures depends on bottom-up self-assembly of amphiphilic biomolecules. Inspired by the unique physicochemical properties of hydrophobic perfluorocarbons, coupled with the powerful functions of nucleic acids, we herein report the synthesis of a series of diperfluorodecyl-DNA conjugates (PF-DNA) which can efficiently self-assemble into micelles in aqueous solution. On the basis of the micelle structure, both target binding affinity and enzymatic resistance of the DNA probe can be enhanced. Read More

    Real-Time Monitoring of Tricarboxylic Acid Metabolites in Exhaled Breath.
    Anal Chem 2018 May 16. Epub 2018 May 16.
    Department of Chemistry and Applied Biosciences , ETH Zurich , 8093 Zurich , Switzerland.
    The tricarboxylic acid (TCA) cycle is one of the most important metabolic pathway for cellular respiration in aerobic organisms. It provides and collects intermediates for many other interconnecting pathways and acts as a hub connecting metabolism of carbohydrates, fatty acids, and amino acids. Alteration in intracellular levels of its intermediates has been linked with a wide range of illnesses ranging from cancer to cellular necrosis or liver cirrhosis. Read More

    Laser Cleavable Probes-based Cell Surface Engineering for In-situ Sialoglycoconjugates Profiling by LDI Mass Spectrometry.
    Anal Chem 2018 May 16. Epub 2018 May 16.
    Cell-surface sialoglycoconjugates (sialoglycoproteins & sialoglycolipids) play important roles in cell-cell interactions and related tumor metastasis process. Although there have been some analytical methods to evaluate the sialoglycoconjugates, an effective method providing both qualitative and quantitative information is still deficient. Here we establish an extraction-free, sensitive and high-throughput platform to realize in-situ detection of the cell-surface sialoglycoconjugates on various cell lines, e. Read More

    Application of Calcium-Binding Motif of E-Cadherin for Electrochemical Detection of Pb(II).
    Anal Chem 2018 May 16. Epub 2018 May 16.
    Department of Chemistry , University of Nebraska-Lincoln , Lincoln , Nebraska 68588-0304 , United States.
    We report, for the first time, the use of a 13-amino-acid peptide sequence derived from the calcium-binding site of E-cadherin in the fabrication of an electrochemical peptide-based (E-PB) Pb(II) sensor. The sensing mechanism is analogous to that of previously developed E-PB sensors. Binding of Pb(II) rigidifies the surface-immobilized and methylene blue (MB)-modified peptide probe, thereby limiting the accessibility of the tethered MB to the electrode surface. Read More

    Reagentless Detection of Low-Molecular-Weight Triamterene Using Self-Doped TiO2 Nanotubes.
    Anal Chem 2018 May 16. Epub 2018 May 16.
    TiO2 nanotube electrodes were self-doped by electrochemical cathodic polarisation, presumably converting Ti4+ into Ti3+, which demonstrably increased both the conductance and capacitance of the electrodes. One-hundred-fold and two-fold concomitant increases in capacitance and conductance, respectively, were achieved in self-doped TiO2 nanotubes, in comparison to their undoped counterparts. The increase in both capacitance and conductance reveals that Ti3+ states upsurge the density of electronic states, which is ascribed to an existing relationship between conductance and capacitance for mesoscopic structures built up on macroscopic electrodes. Read More

    Probing DNA Hybridization Equilibrium by Cationic Conjugated Polymer for Highly Selective Detection and Imaging of Single-Nucleotide Mutation.
    Anal Chem 2018 May 24. Epub 2018 May 24.
    College of Life Science and Technology , Beijing University of Chemical Technology , Beijing 100029 , China.
    Hybridization-based probes emerge as a promising tool for nucleic acid target detection and imaging. However, the single-nucleotide selectivity is still challenging because the specificity of hybridization reaction is typically low at room temperature. We disclose an effective and simple method for highly selective detection and in situ imaging of single-nucleotide mutation (SNM) by taking the advantages of the specific hybridization of short duplex and the signal amplifying effect of cationic conjugated polymer (CCP). Read More

    Highly sensitive Membrane-based Pressure Sensors (MePS) for real-time monitoring of catalytic reactions.
    Anal Chem 2018 May 16. Epub 2018 May 16.
    Functional, flexible and integrated lab-on-chips, based on elastic membranes, are capable of fine response to external stimuli, so to pave the way for many applications as multiplexed sensors for a wide range of chemical, physical and biomedical processes. Here, we report on the use of elastic thin membranes (TMs), integrated with a reaction chamber, to fabricate a Membrane-based Pressure Sensor (MePS) for reaction monitoring. In particular, the TM becomes the key-element in the design of a highly sensitive MePS capable to monitor gaseous species production in dynamic and temporally fast processes with high resolution and reproducibility. Read More

    Determination of Hexavalent Chromium Fractions in Plastics Using Laboratory-Based, High-Resolution X-ray Emission Spectroscopy.
    Anal Chem 2018 May 24. Epub 2018 May 24.
    Chemical Sciences Division , National Institute of Standards and Technology , Gaithersburg , Maryland 20899-8391 , United States.
    Cr(VI) is a well-known human carcinogen with many water-soluble moieties. Its presence in both natural and man-made substances poses a risk to public health, especially when contamination of groundwater is possible. This has led the European Union and other jurisdictions to include Cr(VI) in restriction of hazardous substances regulations. Read More

    Triple-Wavelength-Region Luminescence Sensing Based on a Color-Tunable Emitting Lanthanide Metal Organic Framework.
    Anal Chem 2018 May 22. Epub 2018 May 22.
    Key Laboratory of Functional Inorganic Material Chemistry (MOE) and School of Chemistry and Materials Science , Heilongjiang University , Harbin 150080 , P. R. China.
    A series of isomorphic lanthanide metal-organic frameworks (Ln-MOFs), namely [Ln(dcbba)(DMF)] ·HO·0.5DMF [Ln = La (1), Eu (2) and Tb (3); Hdcbba = 4-(3, 5-dicarboxylatobenzyloxy)benzoic acid; DMF = N, N'-dimethylformamide] have been designed and synthesized by the solvothermal reactions of Hdcbba and La(NO)·6HO. Single-crystal X-ray diffraction analysis reveals that the complexes 1-3 exhibit a (3,6)-connected open framework structure with binuclear [Ln(COO)] secondary building units as 6-connected nodes and Hdcbba ligands as 3-connected nodes. Read More

    Wavelength Modulated Back-Scatter Interferometry for Universal, On-Column Refractive Index Detection in Picoliter Volumes.
    Anal Chem 2018 May 24. Epub 2018 May 24.
    Ralph N. Adams Institute for Bioanalytical Chemistry , University of Kansas , 2030 Becker Drive , Lawrence , Kansas 66047 , United States.
    Wavelength-modulated back scatter interferometry (M-BSI) is shown to improve the detection metrics for refractive index (RI) sensing in microseparations. In M-BSI, the output of a tunable diode laser is focused into the detection zone of a separation channel as the excitation wavelength is rapidly modulated. This spatially modulates the observed interference pattern, which is measured in the backscattered direction. Read More

    Beyond Fourier Transform Infrared Spectroscopy: External Cavity Quantum Cascade Laser-Based Mid-infrared Transmission Spectroscopy of Proteins in the Amide I and Amide II Region.
    Anal Chem 2018 May 24. Epub 2018 May 24.
    Institute of Chemical Technologies and Analytics , Vienna University of Technology , Getreidemarkt 9/164-UPA , 1060 Vienna , Austria.
    In this work, we present a setup for mid-IR measurements of the protein amide I and amide II bands in aqueous solution. Employing a latest generation external cavity-quantum cascade laser (EC-QCL) at room temperature in pulsed operation mode allowed implementing a high optical path length of 31 μm that ensures robust sample handling. By application of a data processing routine, which removes occasionally deviating EC-QCL scans, the noise level could be lowered by a factor of 4. Read More

    Semi-quantitative nucleic acid test with simultaneous isotachophoretic extraction and amplification.
    Anal Chem 2018 May 15. Epub 2018 May 15.
    Nucleic acid amplification tests (NAATs) provide high diagnostic accuracy for infectious diseases and quantitative results for monitoring viral infections. The majority of NAATs require complex equipment, cold chain dependent reagents, and skilled technicians to perform tests. This largely confines NAATs to centralized laboratories and can significantly delay appropriate patient care. Read More

    Assessment of compressive Raman versus hyperspectral Raman for microcalcification chemical imaging.
    Anal Chem 2018 May 15. Epub 2018 May 15.
    We experimentally implement a compressive Raman technology (CRT) that incorporates chemometric analysis directly into the spectrometer hardware by means of a digital micromirror device (DMD). The DMD is a programmable optical filter on which optimized binary filters are displayed. The latter are generated with an algorithm based on the Cramer-Rao lower bound. Read More

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