Read by QxMD icon Read


Ying Zhou, Haijun Wang, Ying Zhuo, Yaqin Chai, Ruo Yuan
In this work, a ferrocene (Fc)-driven light switch biosensor for ultrasensitive detection of amyloid-β (Aβ) was designed by utilizing the highly-efficient electrochemiluminescent nanomaterials of Ag NCs/TiO2 nanoflowers (NFs) as signal labels. Through combining the TiO2 NFs as the co-reaction accelerator and dissolved O2 as the intrinsic co-reactant to in suit generate strong oxidizing intermediate radical OH•, the electrochemiluminescence (ECL) of Ag NCs on the TiO2 NFs surface could be significantly promoted in comparion with that of pure Ag NCs in solution...
February 22, 2017: Analytical Chemistry
Zhengsheng Mao, Xin Wang, Bingxin Li, Jing Jin, Ming Xu, Youping Liu, Xin Di
Matrix effects have been a major concern when developing LC-MS/MS methods for quantitative bioanalysis of cycloserine. Sample handling procedures including solid phase extraction or derivatization have been reported previously by researchers to overcome matrix effects of cycloserine. In the present study, the possibility of reducing matrix effects of cycloserine using protein precipitation coupled with dilution techniques was investigated. Plasma samples were pretreated by protein precipitation with methanol followed by a 40-fold dilution with methanol-water (50:50, v/v)...
February 21, 2017: Analytical and Bioanalytical Chemistry
Lizhen Chen, Jie Chao, Xiangmeng Qu, Hongbo Zhang, Dan Zhu, Shao Su, Ali Aldalbahi, Lianhui Wang, Hao Pei
Adenosine triphosphate (ATP) is a central metabolite that is of critical importance in many cellular processes. The development of sensitive and selective methods for the detection of ATP level in vivo is crucial in diagnostic and theranostic applications. In this work, we have developed a polyA-based aptamer nanobeacon (PAaptNB) with improved efficiency and speed of ATP analysis. We found that the dissociation constants and competitive binding kinetics of the PAaptNB could be programmably regulated by adjusting the polyA length...
February 21, 2017: ACS Applied Materials & Interfaces
Mohamed Abdel-Rehim, Milton L Lee, Barbara Bojko
No abstract text is available yet for this article.
February 1, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Zhuoliang Liu, Xingyu Luo, Zhu Li, Yan Huang, Zhou Nie, Hong-Hui Wang, Shouzhuo Yao
Fluorogenic probes targeting G-quadruplex structures have emerged as the promising toolkit for functional research of G-quadruplex and biosensor development. However, their biosensing applications are still largely limited in in-tube detection. Herein, we proposed a fluorescent bioimaging method based on enzyme-generated G-quadruplexes for detecting apoptotic cells at the cell and tissue level, namely, terminal deoxynucleotidyl transferase (TdT)-activated de novo G-quadruplex synthesis (TAGS) assay. The detection target is genomic DNA fragmentation, a biochemical hallmark of apoptosis...
February 7, 2017: Analytical Chemistry
Jian Shu, Zhenli Qiu, Zhenzhen Lin, Guoneng Cai, Huanghao Yang, Dianping Tang
Photoelectrochemical (PEC) measurement has been developed rapidly for bioanalysis in recent years. However, the actual application for most existed PEC bioanalytical systems is still a challenge because the perfect solutions for sensing surface design, high-throughput detection, and portability are lacked. To successfully overcome these limitations and realize accurate, continuous screening and assessing on prognostic indicator of early stage cancer on the spot, an innovative and portable semiautomated support power-free photoelectrochemical (SP-PEC) immunosensing platform consisted with a miniature semiautomatic injection system and digital multimeter (DMM) readout is designed (prostate specific antigen, PSA, was used as the proof-of-concept analyte)...
December 20, 2016: Analytical Chemistry
Hongmei Chen, Han Zhang, Ruo Yuan, Shihong Chen
Generally, electrochemiluminescence (ECL) ratiometric assays were based on the energy transfer (ET) between an emitter and a metal nanomaterial or between two different emitters. The choice of suitable energy donor-acceptor pair and the distance dependence of ET would greatly limit the practical application of ratiometric assays. This work explored a novel double-potential ECL ratiometry without the ET for organophosphorus pesticides (OPs) analysis, in which, reduced graphene oxide-CdTe quantum dots (RGO-CdTe QDs) and carboxyl-conjugated polymer dots (PFO dots) were chosen as cathodic and anodic ECL emitters, and the reactant (dissolved O2) and the product (H2O2) in enzymatic reactions served as their coreactants, respectively...
February 16, 2017: Analytical Chemistry
David S Nakhla, Lobna A Hussein, N Magdy, Inas A Abdallah, Hazem E Hassan
A sensitive high-performance liquid chromatography (HPLC) assay with dual UV detection has been developed and validated for the simultaneous quantification of methadone and cocaine in rat serum and brain tissue samples. Liquid-liquid extraction using hexanes was applied for samples extraction with Levo-Tetrahydropalmatine (L-THP) as the internal standard. Chromatographic separation of the analytes was achieved on a reversed-phase Waters Symmetry(®) C18 column (150mm×4.6mm, 5μm). A gradient elution was employed with a mobile phase consisting of 5mM potassium phosphate containing 0...
February 7, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Xiu-Li Wang, Ru Sun, Wei-Jin Zhu, Xin-Long Sha, Jian-Feng Ge
Oxazinium derivatives have recently played an important role in bioanalysis attributing to the distinguished properties, thus a detailed study of the structure-property relationship is especially significant. Herein, pH-sensitive optical properties of Nile Blue (1a), N-monoalkyl-Nile Blue (1b) and Azure A (1c) have been carried out in extreme acid and base conditions. Dyes 1a and 1c showed colorimetric changes by the protonation of nitrogen atom in strong acidic condition (pH < 2.0), and dyes 1a - c exhibited colorimetric changes by equilibrium between amino and imide groups in very strong basic case (pH > 7...
February 6, 2017: Journal of Fluorescence
Lihua Qu, Jing Qian, Ping Ma, Zheng Yin
Amphotericin B (AMB), fluconazole (FZ), and fluorocytosine (FC) are recommended for HIV-associated cryptococcal meningitis (CM) patients as preferred antibiotics. This study presents a fast and automated online-dual-solid phase extraction (SPE)-LC coupled with high resolution mass spectrometer (HRMS) method to simultaneously measure the concentrations of AMB, FZ, and FC in human plasma and cerebrospinal fluid (CSF). Automated sample clean-up was performed on the human plasma and CSF samples with stop-flow heart-cutting two dimensional (2D) separation using a online-dual-SPE system, allowing retention and accumulation of AMB, FZ, and carbamazepine (CBZ, Internal standard (IS)) by the Oasis(®)HLB cartridge, and retention and accumulation of FC and 5-methylcytosine hydrochloride (MC, IS) by the HyperSep Hypercarb cartridge respectively...
April 1, 2017: Talanta
Min Meng, Nan Zhao, Carrie C Pederson, Edward Harrison, Charisse Green, Steven H Gorman, Scott Reuschel
Loxapine is an antipsychotic medication used for the treatment of schizophrenia. In vivo, loxapine is metabolized to multiple metabolites. A high performance liquid chromatographic-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the determination of loxapine and 4 of its metabolites, loxapine N-oxide, amoxapine (N-desmethyl loxapine), 8-hydroxyloxapine and 7-hydroxyloxapine, in human plasma to support regulated clinical development. During method development, several technical challenges such as poor chromatography, separation of structural isomers, and inadequate sensitivity were met and overcome...
January 9, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Minh-Kha Nguyen, Wei-Nien Su, Bing-Joe Hwang
Interactions between substrate and plasmonic nanostructures can give rise to unique optical properties and influence performance in plasmonic biosensing applications. In this study, a substrate with low refractive index and roughness based on flower-like alumina-coated etched aluminum foil (f-Al2 O3 /e-Al) has been fabricated. Silver@silica (Ag@SiO2 ) nanocubes (NCs) assemble in an edge-edge configuration when deposited on this substrate. The rough surface texture of f-Al2 O3 /e-Al provides a pathway for coupling of incident light to surface plasmons...
February 2, 2017: Advanced Healthcare Materials
Yaju Zhao, Danke Xu, Weihong Tan
Detection of rare circulating tumor cells (CTCs) in peripheral blood is a challenging, but necessary, task in order to diagnose early onset of metastatic cancer and to monitor treatment efficacy. Over the last decade, step-up produced aptamers have attracted great attention in clinical diagnosis. They have offered great promise for a broader range of cell-specific recognition and isolation. In particular, aptamer-functionalized magnetic particles for selective extraction of target CTCs have shown reduced damage to cells and relatively simple operation...
February 1, 2017: Integrative Biology: Quantitative Biosciences From Nano to Macro
Alessia Stornetta, Peter W Villalta, Frederike Gossner, William R Wilson, Silvia Balbo, Shana J Sturla
PR104A is an experimental DNA-alkylating hypoxia-activated prodrug that can also be activated in an oxygen-independent manner by the two-electron aldo-keto reductase 1C3. Nitroreduction leads to the formation of cytotoxic hydroxylamine (PR104H) and amine (PR104M) metabolites, which induce DNA mono and cross-linked adducts in cells. PR104A-derived DNA adducts can be utilized as drug-specific biomarkers of efficacy and as a mechanistic tool to elucidate the cellular and molecular effects of PR104A. Toward this goal, a mass spectrometric bioanalysis approach based on a stable isotope-labeled adduct mixture (SILAM) and selected reaction monitoring (SRM) data acquisition for relative quantitation of PR104A-derived DNA adducts in cells was developed...
February 19, 2017: Chemical Research in Toxicology
Brigitte Desharnais, Félix Camirand-Lemyre, Pascal Mireault, Cameron D Skinner
Calibration model selection is required for all quantitative methods in toxicology and more broadly in bioanalysis. This typically involves selecting the equation order (quadratic or linear) and weighting factor correctly modelizing the data. A mis-selection of the calibration model will generate lower quality control (QC) accuracy, with an error up to 154%. Unfortunately, simple tools to perform this selection and tests to validate the resulting model are lacking. We present a stepwise, analyst-independent scheme for selection and validation of calibration models...
January 30, 2017: Journal of Analytical Toxicology
Yue Li, An Guo, Lan Chang, Wen-Juan Li, Wen-Juan Ruan
Metal-organic frameworks (MOFs) is emerging in recent years as a kind of versatile fluorescent sensing materials, but their application to enzyme assay has rarely been studied. Herein, we report the first example of MOF based label-free enzyme assay system. A luminescent MOF was synthesized and applied to the activity analysis of polyphenol oxidase (PPO). With its distinct responses to phenolic substrate and o-quinone product, this MOF could transduce the extent of PPO catalyzed oxidation to fluorescence signal and enable the real-time monitoring of this reaction...
January 29, 2017: Chemistry: a European Journal
Inês M Valente, Manuela M Moreira, Pâmela Neves, Thiago da Fé, Luís M Gonçalves, Paulo J Almeida, José A Rodrigues
INTRODUCTION: Salting-out assisted liquid-liquid extraction (SALLE) is a technique that, although simple and not requiring any complex equipment, is very powerful and versatile. It has obtained growing interest in bioanalysis particularly when combined with chromatographic techniques. OBJECTIVES: Herein, fennel seeds (Foeniculum vulgare Mill.) were used as a case-study to show the application of SALLE in phytochemical analysis. MATERIAL AND METHODS: SALLE combined with HPLC-UV-MS/MS and GC-MS...
January 26, 2017: Phytochemical Analysis: PCA
Ala F Nassar, Adam V Wisnewski, Khadir Raddassi
Analysis of multiplexed assays is highly important for clinical diagnostics and other analytical applications. Mass cytometry enables multi-dimensional, single-cell analysis of cell type and state. In mass cytometry, the rare earth metals used as reporters on antibodies allow determination of marker expression in individual cells. Barcode-based bioassays for CyTOF are able to encode and decode for different experimental conditions or samples within the same experiment, facilitating progress in producing straightforward and consistent results...
January 26, 2017: Analytical and Bioanalytical Chemistry
Mazaher Ahmadi, Hatem Elmongy, Tayyebeh Madrakian, Mohamed Abdel-Rehim
In recent years, application of nanomaterials as sorbent has gained the attention of researchers in bioanalysis. Different nanomaterials have been utilized as the sorbent in extraction techniques such as solid phase extraction, dispersive solid phase extraction, magnetic solid phase extraction, microextraction by packed sorbent, solid phase microextraction, dispersive μ-solid phase extraction, and stir bar sorptive extraction. In the present review, different nanomaterials which have recently been utilized as sorbent for bioanalysis are classified into six main groups, namely metallic, metallic and mixed oxide, magnetic, carbonaceous, silicon, and polymer-based nanomaterials...
March 15, 2017: Analytica Chimica Acta
Haiyin Li, Jiafu Chang, Ting Hou, Feng Li
It is well-known that the horseradish peroxidase- (HRP-) mimicking DNAzyme, namely, hemin/G-quadruplex, can effectively catalyze the polymerization of aniline to form DNA-guided polyaniline. Meanwhile, polyaniline exhibits extraordinary electrical, electrochemical, and redox properties, as well as excellent SPR signal-enhancing ability. Herein, we report a novel ultrasensitive surface plasmon resonance (SPR) biosensor based on HRP-mimicking DNAzyme-catalyzed in situ formation of polyaniline for signal amplification, using bleomycin (BLM) as the proof-of-concept analyte...
January 3, 2017: Analytical Chemistry
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"