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PubMed Journal Database | Analytical chemistry RSS

09:31 EDT 27th May 2019 | BioPortfolio

The US National Library of Medicine and National Institutes of Health manage PubMed.gov which comprises of more than 29 million records, papers, reports for biomedical literature, including MEDLINE, life science and medical journals, articles, reviews, reports and  books.

BioPortfolio aims to cross reference relevant information on published papers, clinical trials and news associated with selected topics - speciality.

For example view all recent relevant publications on Epigenetics and associated publications and clincial trials.

Showing PubMed Articles 1–25 of 1,700+ from Analytical chemistry

Electrochemical Aptasensor for Ultralow Fouling Cancer Cell Quantification in Complex Biological Media Based on Designed Branched Peptides.

The rapid, convenient and selective assaying of clinical targets directly in complex biological media brings with it the potential to revolutionise diagnostics. One major hurdle to impact is retention of selectivity as 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 b...

Monitoring Biohydrogen Production and Metabolic Heat in Biofilms by Fiber-Bragg-Grating Sensors.

A fiber Bragg grating (FBG) was created to accurately and simultaneously monitor the biohydrogen and metabolic heat production in biofilms containing Rhodopseudomonas palustris CQK-01 photosynthetic bacteria (PSB). The proposed hydrogen sensor was made from an FBG unit separated into two regions by a wet etching process; a thin region with a diameter of 15 μm was employed to monitor the temperature. A smaller region of the etched FBG with a diameter of 8.0 μm was coated with a 50-nm-thick Pd film by sputt...

Laser ablation-inductively coupled plasma time-of-flight mass spectrometry imaging of trace elements at single cell level for clinical practice.

In this work a combination of routine clinical practice and state-of-the-art laser ablation-inductively coupled plasma time-of-flight mass spectrometry (LA-ICP-TOFMS) imaging is presented for multi-element analysis of single cells on clinical samples. More specifically, routinely drawn blood thin films of a patient undergoing treatment with the anticancer drug cisplatin were studied. The presented label-free approach enabled rapid analysis of hundreds of cells at single cell level within few minutes without...

A Competitive Pull-down Assay Using G-quadruplex DNA Linked Magnetic Nanoparticles to Determine Specificity of G-quadruplex Ligands.

Herein we develop a new competitive screening method in which G-quadruplex DNA linked magnetic nanoparticles pull down selective ligands for a particular quadruplex topology from a series of small molecules. The screening strategy is first optimized with known G-quadruplex ligands and then used with a series of newly synthesized G-quadruplex interactive bis-triazolyl ligands by Cu(I) catalyzed azide-alkyne cycloaddition. The assay enables the identification of c-MYC and BCL2 G-quadruplex selective bis-triaz...

Resistive-Pulse Sensing and Surface Charge Analysis of Single Nanoparticle Collision at a Conical Glass Nanopore.

In this study, the collision of monodispersed single Au@SiO2 nanoparticles (NPs, ~ 83.5 ± 6.5 nm) at the outer orifice of a smaller-sized (~ 40±8 nm) conical glass nanopore was systematically investigated by the resistive-pulse sensing technique, under three different surface charge states. When NPs approach the nanopipette orifice and collide, the ionic current changes dramatically, and the collision current amplitude showed a linear relationship with the potential bias applied. In our system the electro...

Measurement of free drug concentration from biological tissue by Solid-phase Microextraction: In-Silico and Experimental Study.

In this article, the use of an SPME technique is reported for the first time for direct measurement of free drug concentration in solid tissue. In our investigations, we considered doxorubicin (DOX) spiked in homogenized tissue matrix at transient and equilibrium extraction conditions, with subsequent assessment of obtained experimental results by an in-silico approach using mathematical models developed in COMSOL Multiphysics. In-silico studies were performed based on transported diluted species (tds) and ...

Stand-off hyperspectral Raman imaging and random decision forest classification: a potent duo for the fast, remote identification of explosives.

In this study we present a stand-off hyperspectral Raman imager (HSRI) for the fast detection and classification of differ-ent explosives at a distance of 15 m. The hyperspectral image cube is created by using a liquid crystal tunable filter (LCTF) to select a specific Raman shift and sequentially imaging spectral images onto an intensified CCD camera. The laser beam is expanded to illuminate the field of view of the HSRI and thereby improves large area scanning of suspicious surfaces. The collected hypersp...

Turn-on Fluorescent Detection of Hydrogen Peroxide and Triacetone Triperoxide via Enhancing Interfacial Interactions of a Blended System.

In this work, we report the fabrication of a blend consisting of fluorescent 1 nanofibers and amberlyst-15 particles as a turn-on fluorescence sensor for trace TATP vapors. Fluorescence imaging and lifetime analysis reveal that the interface between 1 nanofibers and amberlyst-15 particles exhibits stronger photoluminescence than the unblended areas because of the formed strong hydrogen bonding in between. Furthermore, the interfacial adhesion between 1 nanofibers and amberlyst-15 particles can be amplified ...

Selective Fabrication of Nanowires with High Aspect-Ratios using a Diffusion Mixing Reaction System for Applications in Temperature Sensing.

The selective fabrication of highly ordered nanowires with high aspect ratios was of low reproducibility, which remains a challenge for laboratory research. In this paper, we report a novel approach for selective fabrication of conductive nano-wires on a solid surface via diffusion mixing reaction system formed by a chemical pen. The nanoscale-mixing region was achieved by appropriately adjusting the viscosity of the solution and other parameters with the aid of dyes functioned as a flow boundary indicator....

Establishment of logic gates based on conformational changes in multiple-factor biomolecule interaction process by dual polarization interferometry.

DNA-based logic gates stimulate the development of molecular scale computers and show enormous potential in nanotechnology, biotechnology, and medicine. However, the reported detectors to date usually require label an appropriate signal probes, resulting in not only a high cost but also potentially tedious manipulation. For the first time, we established label-free logic gate by regarding the structure-related signal as output. Dual polarization interferometry (DPI) was employed to reveal the detailed confo...

Improved polycyclic aromatic hydrocarbons and n-alkanes determination in speleothems through cleanroom sample processing.

The interest in paleoenvironmental reconstructions from biomarkers in speleothems is increasing, thanks in part to the capacity of speleothems to grow continuously and to resist post-depositional alteration. In particular, the possibility exists to link high-resolution and accurately dated fire and vegetation records with isotopic data of climatic and paleoenvironmental interactions at the local and regional scale. However, the scarcity of existing methods for the quantification of organic molecules in stal...

Drift Subtraction for FSCV Using Double-Waveform Partial-Least-Squares Regression.

Background-subtracted fast-scan cyclic voltammetry (FSCV) provides a method for detecting molecular fluctuations with high spatiotemporal resolution in the brain of awake and behaving animals. The rapid scan rates generate large background currents that are subtracted to reveal changes in analyte concentration. Although these background currents are relatively stable, small changes do occur over time. These changes, referred to as electrochemical drift, result in background-subtraction artifacts that constr...

Initial Development Towards Non-Invasive Drug Monitoring via Untargeted Mass Spectrometric Analysis of Human Skin.

Drug monitoring is crucial for providing accurate and effective care; however, current methods (e.g. blood draws) are inconvenient and unpleasant. We aim to develop a non-invasive method for the detection and monitoring of drugs via human skin. The initial development towards this aim required information about which drugs, taken orally, can be detected from the skin. Untargeted liquid chromatography - mass spectrometry (LC-MS) was used as it was unclear if drugs, known drug metabolites, or other transforma...

A comprehensive UHPLC ion mobility QTOF method for profiling and quantification of eicosanoids, other oxylipins and fatty acids.

Analysis of oxylipins by liquid chromatography mass spectrometry (LC/MS) is challenging because of the small mass range occupied by this diverse lipid class, the presence of numerous structural isomers, and their low abundance in biological samples. Although highly sensitive LC/MS/MS methods are commonly used, further separation is achievable by using drift tube ion mobility coupled with high-resolution mass spectrometry (DTIM-MS). Herein, we present a combined analytical and computational method for the id...

Development and Evaluation of a 66-Well Plate Using a Porous Sorbent in a Four-Phase Extraction Assisted by Electric Field Approach.

In this work, cellulose cone tips were used as a hydrophilic sorbent supporting an aqueous electrolyte solution in a four-phase electric-field-assisted extraction. The wetted tips were immersed in an immiscible organic phase, acting as a filter to extract analytes present in an aqueous sample. Simultaneous four-phase extractions were carried out under the influence of an electric field using a 66-well plate constructed with inexpensive and readily available laboratory materials. Several parameters that cont...

An electrochemical biosensor based on tetrahedral DNA nanostructures and G-quadruplex/hemin conformation for the ultrasensitive detection of microRNA-21 in serum.

MicroRNAs (miRNAs) play an important role as significant biomarkers in disease diagnostics. Here, an electrochemical biosensor was developed for the quick, sensitive and specific detection of miRNAs from human serum samples using three-dimensional (3D) DNA tetrahedron-structured probes (TSPs) and duplex-specific nuclease (DSN). The designed TSPs were composed of a recognition sequence that corresponded to a target miRNA and G-quadruplex sequence that was combined with hemin to mimic the biocatalytic functio...

Exploiting the dynamic relationship between peptide separation quality and peptide co-isolation in a mPSM approach offers a new strategy to optimize bottom-up proteomics throughput and depth.

Peptide co-fragmentation leads to chimeric MS/MS spectra that negatively impact traditional single-peptide match-per-spectrum (sPSM) search strategies in proteomics. The collection of chimeric spectra is influenced by peptide co-elution and the width of precursor isolation windows. Although peptide co-fragmentation can be reduced by advanced chromatography, such as UHPLC and 2D-HPLC separation schemes, and narrower isolation windows, chimeric spectra can still be as high as 30-50% of the total MS/MS spectra...

Site-specific immobilization of β2-AR using O6-benzylguanine derivative-functionalized supporter for high throughput receptor-targeting lead discovery.

The last decade has witnessed the great promise of strategies for ligand discovery based on surface-immobilized GPCRs. We present here a method for preparation of immobilized GPCRs. Key features include covalent immobilization with high specificity and robust application in drug-receptor interaction analysis and ligand screening. In our example assay using beta2-adrenergic receptor (β2-AR), the human DNA repair protein O6-alkylguanine-DNA alkyltransferase (hAGT) fusion receptor expressed in Escherichia col...

Sr Isotope Analysis of Picogram-level Samples by Thermal Ionization Mass Spectrometry Using a Highly Sensitive Silicotungstic Acid Emitter.

Thermal ionization mass spectrometry (TIMS) has shown excellent analytical precision for Sr isotopic ratio analysis, even for small masses of material (0.5-10 ng). However, because of the sensitivity limit of TIMS, it is still not possible to obtain high precision 87Sr/86Sr isotope ratios for picogram-level sample sizes (30-100 pg) due to the lack of a highly sensitive emitter. This study is the first to employ a highly sensitive silicotungstic acid emitter to measure Sr isotopes at the picogram-level using...

Sub-ppt level detection of analytes by superhydrophobic pre-concentration paper spray ionization mass spectrometry (SHPPSI MS).

A new kind of ambient ionization method named as superhydrophobic pre-concentration paper spray ionization mass spectrometry (SHPPSI MS) is introduced; where, superhydrophobicity and paper spray mass spectrometry (PS MS) are coupled. The SHPPSI MS requires only microliter amounts of analyte solutions, allows easy sampling procedure and provides high sensitivity for a diverse array of analytes. It can be used to detect food adulteration at extremely low concentrations. The experimental methodology involves m...

Profiling of Human Milk Oligosaccharides for Lewis Epitopes and Secretor Status by Electrostatic Repulsion Hydrophilic Interaction Chromatography Coupled with Negative-Ion Electrospray Tandem Mass Spectrometry.

Human milk oligosaccharides (HMOs) are one of the most abundant ingredients in breast milk, and play a beneficial role for newborns and are important for infant health. The peripheral fucosylated sequences of HMOs, such as the histo-blood group ABH(O) and Lewis a, b, x, and y antigens, are determined by the expression of the secretor (Se) and Lewis (Le) genes in the mammary gland, and are often the recognition motifs and serve as decoy receptors for microbes. In this work, we developed a method for determin...

Non-targeted pattern recognition in the search for pyrolysis gas chromatography/mass spectrometry resin markers in historic lacquered objects.

A differential expression analysis technology developed for linear modelling of gene expression data was used in combination with thermally assisted hydrolysis and methylation gas chromatography/mass spectrometry (THM-GC/MS) to support the analysis of lacquers and varnishes on historical objects. Exudates from tropical trees such as Manila copal, sandarac, South American copal and Congo copal, which were frequently used in finishing layers on decorative objects up to the early 20th century, were compared th...

Speeding up the line-scan Raman imaging of living cells by deep convolutional neural network.

Raman imaging is a promising technique that allows the spatial distribution of different components in the sample to be obtained by using the molecular fingerprint information of individual species. However, the imaging speed are the bottleneck for the current Raman imaging methods to monitor the dynamic process of living cells. In this paper, we developed an artificial intelligence assisted fast Raman imaging method over the already fast line scan Raman imaging method. The reduced imaging time is realized ...

An Autonomous Microfluidic Device for Generating Volume-defined Dried Plasma Spots (DPS).

Obtaining plasma from a blood sample and preparing it for subsequent analysis is currently a laborious process involving experienced health-care professionals and centrifugation. We circumvent this by utilizing capillary forces and microfluidic engineering to develop an autonomous plasma sampling device that filters and stores an exact amount of plasma as a Dried Plasma Spot (DPS) from a whole blood sample in less than six minutes. We tested 24 prototype devices with whole blood from 10 volunteers, various ...

Extractive Ratio Analysis NMR Spectroscopy for Metabolite Identification in Complex Biological Mixtures.

The complexity of biological mixtures continues to challenge efforts aimed at unknown metabolite identification in the metabolomics field. To address this challenge, we provide a new method to identify related peaks from individual metabolites in complex NMR spectra. Extractive ratio analysis NMR spectroscopy (E-RANSY) builds on our previously described ratio analysis method [Anal. Chem. 2011, 83, 7616-7623] and exploits the simplified NMR spectra provided by the extraction of metabolites under varied pH co...


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