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Analytical Chemistry

Shichu Huang, Koji Abe, Steven Bennett, Tinny Liang, Paula D Ladd, Lindsay Yokobe, Caitlin E Anderson, Kamal Shah, Josh Bishop, Mike Purfield, Peter C Kauffman, Sai Paul, AnneMarie E Welch, Bonnie Strelitz, Kristin Follmer, Kelsey Pullar, Luis Sanchez-Erebia, Emily Gerth-Guyette, Gonzalo J Domingo, Eileen Klein, Janet A Englund, Elain Fu, Paul Yager
A prototype of a self-contained, automated, disposable device for chemically-amplified protein-based detection of influenza virus from nasal swab specimens was developed and evaluated in a clinical setting. The device required only simple specimen manipulation without any dedicated instrumentation or specialized training by the operator for interpretation. The device was based on a sandwich immunoassay for influenza virus nucleoprotein; it used an enzyme-labeled antibody and a chromogenic substrate to provide an amplified visible signal, in a two-dimensional paper network format...
April 26, 2017: Analytical Chemistry
Yuzhi Chen, Xiaomin Shi, Zhengliang Lu, Xuefei Wang, Zhuo Wang
Endogenous hydrogen peroxide in vivo is related to many diseases, including cancer, diabetes, cardiovascular disease, and neurodegenerative disorders. Although many probes for detection of H2O2 have been explored, rapid response probes are still expected for in vivo application. Here, a new probe (PAM-BN-PB) was designed based on an intramolecular charge transfer (ICT) process with three parts: phenanthroimidazole, benzonitrile, and phenyl boronate. By modulation ICT process of PAM-BN-PB, H2O2 in solution systems can be detected with good selectivity...
April 26, 2017: Analytical Chemistry
Lihua Huang, Ning Wang, Charles E Mitchell, Tammy Brownlee, Steven R Maple, Michael R De Felippis
Residual host cell proteins (HCPs) in biopharmaceuticals derived from recombinant DNA technology can present potential safety risks to patients or compromise product stability. Thus, the downstream purification process is designed to demonstrate robust removal of these impurities. ELISA using polyclonal anti-HCP antibodies as reagents for capture, detection, and quantitation purposes is most commonly used to monitor HCP removal during process development, but this technique has limitations. More recently, LC-MS for residual HCP characterization has emerged as a powerful tool to support purification process development...
April 26, 2017: Analytical Chemistry
Miguel Reyes, Marek Piotrowski, Swee Kim Ang, Jingqi Chan, Shuai He, Justin Jang Hann Chu, James Chen Yong Kah
Enterovirus 71 (EV71) is a major public health threat that requires rapid point-of-care detection. Here, we developed a surface-enhanced Raman spectroscopy (SERS)-based scheme that utilized protein-induced aggregation of colloidal gold nanostars (AuNS) to rapidly detect EV71 without the need for fabricating a solid substrate, Raman labels or complicated sample handling. We used AuNS (hydrodynamic diameter, DH of 105.12 ± 1.13 nm) conjugated to recombinant scavenger receptor class B, member 2 (SCARB2) protein with known affinity to EV71...
April 26, 2017: Analytical Chemistry
Rocio J Jimenez-Valdes, Roberto Rodriguez-Moncayo, Diana F Cedillo-Alcantar, Jose L Garcia-Cordero
New tools that facilitate the study of cell-to-cell variability could help uncover novel cellular regulation mechanisms. We present an integrated microfluidic platform to analyze a large number of single cells in parallel. To isolate and analyze thousands of individual cells in multiplexed conditions, our platform incorporates arrays of microwells (7 pL each) in a multilayered microfluidic device. The device allows the simultaneous loading of cells into 16 separate chambers, each containing 4640 microwells, for a total of 74 240 wells per device...
April 26, 2017: Analytical Chemistry
Amanda L Le Sueur, Sashary Ramos, Jonathan D Ellefsen, Silas Cook, Megan C Thielges
Two-dimensional infrared (2D IR) spectroscopy provides a powerful approach for the direct study of molecular dynamics with high spatial and temporal resolution. Its application for investigating specific locations in proteins requires the incorporation of IR probe groups with spectrally isolated absorptions to avoid the congestion inherent to protein spectra. This has motivated extensive efforts toward the development of new IR probes, but there remains a need for those that can extend the experimental time range, which is limited by their vibrational lifetimes...
April 26, 2017: Analytical Chemistry
Syrena C Fernandes, Jenna A Walz, Daniel J Wilson, Jessica C Brooks, Charles R Mace
While a number of assays for soluble analytes have been developed using paper-based microfluidic devices, the detection and analysis of blood cells has remained an outstanding challenge. In this Feature, we discuss how the properties of paper determine the performance of paper-based microfluidic devices and permit the design of cellular assays, which can ultimately impact disparities in healthcare that exist in limited-resource settings.
April 26, 2017: Analytical Chemistry
Pavel V Shliaha, Matthew A Baird, Mogens M Nielsen, Vladimir Gorshkov, Andrew P Bowman, Julia L Kaszycki, Ole N Jensen, Alexandre A Shvartsburg
Histone proteins are subject to dynamic post-translational modifications (PTMs) that cooperatively modulate the chromatin structure and function. Nearly all functional PTMs are found on the N-terminal histone domains (tails) of ∼50 residues protruding from the nucleosome core. Using high-definition differential ion mobility spectrometry (FAIMS) with electron transfer dissociation, we demonstrate rapid baseline gas-phase separation and identification of tails involving monomethylation, trimethylation, acetylation, or phosphorylation in biologically relevant positions...
April 26, 2017: Analytical Chemistry
Laura Freije-Carrelo, Mariella Moldovan, Jose Ignacio Garcia-Alonso, Thuy Diep Thanh Vo, Jorge Ruiz Encinar
Although analysis of metals and metalloids, such as arsenic, is widely spread in many different fields, their analysis in gas and liquefied gas samples is still a challenge. A new GC-ICP-MS set up has been developed for their simultaneous total and speciation analysis in gas and liquefied gas samples without the need of a preconcentration step. An arsine in nitrogen standard was used for optimization and evaluation of the system. Good linearity and detection limits in the very low ppt level for both total and speciation analyses were found...
April 25, 2017: Analytical Chemistry
Marc B Taraban, Roberto A DePaz, Brian Lobo, Yihua Bruce Yu
Formulation stability is a critical attribute of any protein-based biopharmaceutical drug due to a protein's inherent tendency to aggregate. Advanced analytical techniques currently used for characterization of protein aggregates are prone to a number of limitations, and usually require additional manipulations with the sample, such as dilution, separation, labeling and use of special cuvettes. In the present work, we compared conventional techniques for the analysis of protein aggregates with a novel approach that employs the water proton transverse relaxation rate R2(1H2O)...
April 25, 2017: Analytical Chemistry
Mirelis Santos-Cancel, Ryan J White
Electrochemical aptamer-based (E-AB) sensors offer advantageous analytical detection abilities on account of their rapid response time (sec to min), specificity to a target, and selectivity to function in complex media. Ribonucleic acid (RNA) aptamers employed in this class of sensor offer favorable binding characteristics resulting from the ability of RNA to form stable tertiary folds aided by long-range intermolecular interactions. As a result, RNA aptamers can fold into more complex three-dimensional structures than their DNA counterparts, and consequently, exhibit better binding ability to target analytes...
April 25, 2017: Analytical Chemistry
Shuangshou Wang, Yanrong Wen, Yijia Wang, Yanyan Ma, Zhen Liu
Recognition of cancer cells is essential for many important areas such as targeted cancer therapy. Multi-monosaccharide based recognition could be a useful strategy to improve the recognition specificity, but such a possibility has not been explored yet. Herein we report pattern recognition of cells via multiplexed imaging with monosaccharide-imprinted quantum dots (QDs). Imprinted with sialic acid, fucose and mannose as the template respectively, the QDs exhibited good specificity toward the template monosaccharides...
April 25, 2017: Analytical Chemistry
Cheng-Yi Hong, Shu-Xian Wu, Shi-Hua Li, Hong Liang, Shan Chen, Juan Li, Huang-Hao Yang, Weihong Tan
The development of functional DNA-based nanosensors in living cells has experienced some design challenges, including, for example, poor cellular uptake, rapid nuclease degradation, and high false positives. Herein, we designed selectively permeable poly(methacrylic acid) (PMA) nanocapsules to encapsulate functional DNAs for metal ions and small-molecules sensing in living cells. Since functional DNAs are concentrated in the nanocapsules, an increasing reaction rate is obtained in vitro. During endocytosis, polymeric capsules simultaneously improve cellular uptake of functional DNAs and preserve their structural integrity inside the confined capsule space...
April 25, 2017: Analytical Chemistry
Linjing Zhao, Yan Ni, Mingming Su, Hongsen Li, Fangcong Dong, Wenlian Chen, Runmin Wei, Lulu Zhang, Seu-Ping Guiraud, François-Pierre J Martin, Cynthia Rajani, Guoxiang Xie, Wei Jia
The ability to identify and quantify small molecule metabolites derived from gut microbial-mammalian co-metabolism is essential for the understanding of the distinct metabolic functions of the microbiome. To date, analytical protocols that quantitatively measure a complete panel of microbial metabolites in biological samples have not been established, but urgently needed by the microbiome research community. Here, we report an automated high-throughput quantitative method using a gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) platform to simultaneously measure over one hundred microbial metabolites in human serum, urine, feces and Escherichia coli cell samples within 15 minutes per sample...
April 24, 2017: Analytical Chemistry
Jinjie Wang, Xiangyi Huang, Heng Liu, Chaoqing Dong, Jicun Ren
In this work we propose fluorescence and scattering light cross-correlation spectroscopy (FSCCS) based on laser confocal configuration using silver nanoparticle (SNPs) and Alexa Fluor 488 (Alexa) as probe pairs. FSCCS is a single molecule (particle) method, and its principle is similar to that of fluorescence cross-correlation spectroscopy (FCCS). We established the setup of FSCCS using single wavelength laser and developed an immunoassay model of FSCCS. The reliability and adaptability of FSCCS method were evaluated by homogeneous sandwich immunoassay mode...
April 24, 2017: Analytical Chemistry
Hongyu Li, Xiaohua Li, Xiaofeng Wu, Wen Shi, Huimin Ma
Peroxynitrite (ONOO-), an important reactive oxygen species (ROS), may be generated in the mitochondria under various physiological and pathological conditions. In this work, we designed and synthesized a mitochondria-targetable fluorescence probe RPTPP by using rhodamine as the fluorophore, phenylhydrazine as the recognition moiety, and triphenyl- phosphonium cation as the mitochondria-targeting moiety. Upon reaction of the probe with ONOO-, the oxidation of phenylhydrazine by ONOO- and the subsequent hydrolysis opens the non-fluorescent spirocyclic structure and thus triggers a fluorescence turn-on response, which provides a sensitive and selective method for the detection of ONOO-...
April 24, 2017: Analytical Chemistry
Saer Samanipour, Malcolm J Reid, Kevin V Thomas
Liquid chromatography coupled to high resolution mass spectrometry (LC-HR-MS) has been one of the main analytical tools for the analysis of small polar organic pollutants in the environment. LC-HR-MS typically produces a large amount of data for a single chromatogram. The analyst is therefore required to perform prioritization prior to non-target structural elucidation. In the present study we have combined the F-ratio statistical variable selection and the apex detection algorithms in order to perform prioritization in data sets produced via LC-HR-MS...
April 24, 2017: Analytical Chemistry
Martin Breitenlechner, Lukas Fischer, Markus Hainer, Martin Heinritzi, Joachim Curtius, Armin Hansel
We have developed and characterized the novel PTR3, a Proton Transfer Reaction Time-of-Flight mass spectrometer (PTR-ToF) using a new gas inlet and an innovative reaction chamber design. The reaction chamber consists of a tripole operated with RF voltages generating an electric field only in radial direction. An elevated electrical field is necessary to reduce clustering of primary hydronium (H3O(+)) and product ions with water molecules present in the sample gas. The axial movement of the ions is achieved by the sample gas flow only...
April 24, 2017: Analytical Chemistry
Jiaqing Chen, Pei Zhang, Mengying Lv, Huimin Guo, Yin Huang, Zunjian Zhang, Fengguo Xu
Data reduction techniques in gas chromatography-mass spectrometry-based untargeted metabolomics has made the following workflow of data analysis more lucid. However, the normalization process still perplexes researchers, and its effects are always ignored. In order to reveal the influences of normalization method, five representative normalization methods (mass spectrometry total useful signal, median, probabilistic quotient normalization, remove unwanted variation-random, and systematic ratio normalization) were compared in three real data sets with different types...
April 24, 2017: Analytical Chemistry
Tian-Jia Jiang, Meng Yang, Shan-Shan Li, Ming-Jun Ma, Nan-Jing Zhao, Zheng Guo, Jin-Huai Liu, Xing-Jiu Huang
Traditional laser-induced breakdown spectroscopy (LIBS) always fails to directly detect target in aqueous solution due to rapid quenching of emitted light and adsorption of pulse energy by surrounding water. A method is proposed for the in situ underwater LIBS analysis of Cr(VI) in aqueous solution freed from the common problems mentioned above by combining a gas-assisted localized liquid discharge apparatus with electrosorption for the first time. In this approach, the introduction of the gas-assisted localized liquid discharge apparatus provides an instantaneous gaseous environment for underwater LIBS measurement (that is, the transfer of sampling matrix is not needed from aqueous solution to dry state)...
April 24, 2017: Analytical Chemistry
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