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Analytical Chemistry

Ling Lin, Xuexia Lin, Luyao Lin, Qiang Feng, Takehiko Kitamori, Jin-Ming Lin, Jiashu Sun
Interaction between tumor and endothelial cells could affect tumor growth and progression, and induce drug resistance during cancer therapy. Investigation on tumor-endothelial cell interaction involves cell co-culture, protein detection, and analysis of drug metabolites, which are complicated and time-consuming. In this work, we present an integrated microfluidic device with three individual components (the cell co-culture component, the protein detection component, and the pre-treatment component for drug metabolites) to probe the interaction between tumor and endothelial cells...
August 18, 2017: Analytical Chemistry
Shuo Wang, Lihong Li, Shenghao Jin, Weifeng Li, Wei Hang, Xiaomei Yan
Semiconducting quantum dots (QDs) are finding a wide range of biomedical applications due to their intense fluorescence brightness and long-term photostability. Here, we report precise quantification of the fluorescence intensity of single QDs on a laboratory-built high-sensitivity flow cytometer (HSFCM). The nearly uniform illumination of the particles at the intense portions of the radiation field resulted in narrowly distributed signals with high signal-to-noise ratios. By analyzing thousands of QDs individually in as little time as 1 min, intrinsic polydispersity was quickly revealed in a statistically robust manner...
August 18, 2017: Analytical Chemistry
Weili Chen, Hojeong Yu, Fu Sun, Akid Ornob, Ryan Brisbin, Anurup Ganguli, Vinay Kumar Vemuri, Piotr Strzebonski, Guangzhe Cui, Karen J Allen, Smit A Desai, Weiran Lin, David M Nash, David Hirschberg, Ian Brooks, Rashid Bashir, Brian T Cunningham
New tools are needed to enable rapid detection, identification, and reporting of infectious viral and microbial pathogens in a wide variety of point-of-care applications that impact human and animal health. We report the design, construction, and characterization of a platform for multiplexed analysis of disease-specific DNA sequences that utilizes a smartphone camera as the sensor in conjunction with a handheld "cradle" that interfaces the phone with a silicon-based microfluidic chip embedded within a credit card-sized cartridge...
August 18, 2017: Analytical Chemistry
Mehedhi Hasan, Swaminathan Venkatesan, Dmitry A Lyashenko, Jason D Slinker, Alex Zakhidov
Organohalide lead (hybrid) perovskites have emerged as competitive semiconducting materials for photovoltaic devices due to their high performance and low cost. To further the understanding and optimization of these materials, solution based methods for interrogating and modifying perovskite thin films are needed. In this work, we report hydrofluoroether (HFE) solvent based electrolyte for electrochemical processing and characterization of organic-inorganic trihalide lead perovskite thin films. Organic perovskite films are soluble in most of the polar organic solvents and thus until now they were not considered suitable for electrochemical processing...
August 18, 2017: Analytical Chemistry
Ran Chen, Ryan James Balla, Alex Lima, Shigeru Amemiya
Nanoscale scanning electrochemical microscopy (SECM) is a powerful scanning probe technique that enables high-resolution imaging of chemical processes at single nanometer-sized objects. However, it has been a challenging task to quantitatively understand nanoscale SECM images, which requires to accurately characterize the size and geometry of nanoelectrode tips. Herein, we address this challenge through transmission electron microscopy (TEM) of quartz nanopipets for SECM imaging of single solid-state nanopores by using nanopipet-supported interfaces between two immiscible electrolyte solutions (ITIES) as tips...
August 18, 2017: Analytical Chemistry
Deying Chen, Wei Han, Xiaoling Su, Liang Li, Lanjuan Li
Blood is widely used for discovery metabolomics to search for disease biomarkers. However, blood sample matrix can have a profound effect on metabolome analysis, which can impose an undesirable restriction on the type of blood collection tubes that can be used for blood metabolomics. We investigated the effect of blood sample matrix on metabolome analysis using a high-coverage and quantitative metabolome profiling technique based on differential chemical isotope labeling (CIL) LC-MS. We used (12)C-/(13)C-dansylation LC-MS to perform relative quantification of the amine/phenol submetabolomes of four types of samples (i...
August 18, 2017: Analytical Chemistry
Ting Zhang, Zi-Yu Li, Qing-Yu Liu, Sheng-Gui He
Although the use of proton-transfer-reaction mass spectrometry (PTR-MS) in real-time measurements of atmospheric volatile organic compounds (VOCs) has expanded rapidly in recent years, PTR-MS has several serious limitations related to H3O(+) reagent ion chemistry, such as considerable fragmentation for large alkanes, low sensitivity to formaldehyde, and inability to separate isomeric aldehydes and ketones. One of the key means to address these limitations is to develop other appropriate reagent ions. In this paper, the reactivity of Au(+) toward large n-alkanes (C7-C10), formaldehyde, acetaldehyde, propanal, and acetone under high-pressure buffer gas has been explored by mass spectrometry and theoretical calculations...
August 18, 2017: Analytical Chemistry
Zuhao Zhu, Juris Meija, Airong Zheng, Zoltan Mester, Lu Yang
Like many other elements, iridium is lacking a calibrated, SI traceable isotope ratio measurement. In this study, we have undertaken absolute isotope amount ratio measurements of iridium by multicollector inductively coupled plasma mass spectrometry (MC-ICPMS) using a state-of-the-art regression model to correct for the instrumental fractionation (mass bias) of isotope ratios using both NIST SRM 997 isotopic thallium and NIST SRM 989 isotopic rhenium as primary calibrators. The optimized regression mass bias correction model is based on incrementally increasing plasma power and short (10-30 min) measurement sessions...
August 18, 2017: Analytical Chemistry
Haiyin Li, Chuanfeng Wang, Ting Hou, Feng Li
The development of ultrasensitive and highly selective fluorescence biosensors for diverse analytes is highly desirable but remains a challenge. It is attributable to the scarcity of fluorogens with promising brightness, stability, and nontoxicity, which primarily determine the performance of fluorescence biosensors. Herein, we report the design and preparation of aggregation induced emission (AIE) dots with high brightness, exceptional colloidal stability, ultrasmall size, and functional groups for developing ultrasensitive biosensor through the electrostatic conjugation to biological molecules, and use blemycin (BLM) as the proof-of-concept analyte...
August 18, 2017: Analytical Chemistry
Nathalie Scheuble, Alexander Iles, Robert C R Wootton, Erich J Windhab, Peter Fischer, Katherine S Elvira
Quantifying the impact of environmental physicochemical changes on the microstructure of lipid delivery systems is challenging. Therefore, we have developed a methodology to quantify the coalescence of oil-in-water emulsion droplets during lipid digestion in situ on a single droplet level. This technique involves a custom-made glass microfluidic platform, in which oil droplets can be trapped as single droplets, or several droplets per trap. The physicochemical environment can be controlled, and droplet digestion, as well as coalescence, can be visualized...
August 18, 2017: Analytical Chemistry
Xuefei Gao, Peng Zheng, Sujan Kasani, Steven Wu, Feng Yang, Sara Lewis, Sara Nayeem, Elizabeth Engler-Chiurazzi, Jane Wigginton, James W Simpkins, Nianqiang Wu
An inexpensive and disposable paper-based lateral flow strip (PLFS) has been developed as an immunoassay, in which surface-enhanced Raman scattering (SERS) is utilized for sensing signal transduction. The Au nanostar@Raman Reporter@silica sandwich nanoparticles are developed as the SERS probes, which is the key to high sensitivity of device. Compared with a colorimetric PLFS, the SERS-PLFS exhibits superior performance in terms of sensitivity and limit of detection (LOD) in a blood plasma-containing sample matrix...
August 17, 2017: Analytical Chemistry
Daoli Zhao, David Siebold, Noe T Alvarez, Vesselin N Shanov, William R Heineman
In this work, all three electrodes in an electrochemical cell were fabricated based on carbon nanotube (CNT) thread. CNT thread partially insulated with a thin polystyrene coating to define the microelectrode area was used as the working electrode; bare CNT thread was used as the auxiliary electrode; and a micro quasi-reference electrode was fabricated by electroplating CNT thread with Ag and then anodizing it in chloride solution to form a layer of AgCl. The AgǀAgCl coated CNT thread electrode provided a stable potential comparable to the conventional liquid-junction type AgǀAgCl reference electrode...
August 17, 2017: Analytical Chemistry
Zhugen Yang, Gaolian Xu, Julien Reboud, Barbara Kasprzyk-Hordern, Jonathan Mark Cooper
We report a rapid "sample-to-answer" platform for the quantitative monitoring of genetic biomarkers within communities by analysis of wastewater. The assay is based on the loop-mediated isothermal amplification (LAMP) and shows for the first time the ability to rapidly quantify human-specific mitochondrial DNA (mtDNA) from raw untreated wastewater samples. mtDNA provides a model population biomarker associated with carcinogenesis including breast, renal and gastric cancers. We integrated a filter to remove solid impurities and perform DNA extraction and enrichment in a low cost lateral flow-based test...
August 17, 2017: Analytical Chemistry
Dan Yuan, Say Hwa Tan, Ronald Sluyter, Qianbin Zhao, Sheng Yan, N T Nguyen, Jinhong Guo, Jun Zhang, Weihua Li
This work investigates the on-chip washing process of microparticles and cells using coflow configuration of viscoelastic fluid and Newtonian fluid in a straight microchannel. By adding a small amount of biocompatible polymers into the particle medium or cell culture medium, the induced viscoelasticity can push particles and cells laterally from their original medium to the coflow Newtonian medium. This behavior can be used for particle or cell washing. First, we demonstrated on-chip particle washing by the size-dependent migration speed using coflow of viscoelastic fluid and Newtonian fluid...
August 17, 2017: Analytical Chemistry
Jinquan Liu, Hong Cheng, Dinggeng He, Xiaoxiao He, Kemin Wang, Qiaoqiao Liu, Shuaiqi Zhao, Xudong Yang
Presented herein is a simple, robust, and label-free homogeneous electrochemical sensing platform constructed for the detection of protein kinase activity and inhibition by integration of carboxypeptidase Y (CPY)-assisted peptide cleavage reaction and vertically ordered mesoporous silica films (MSFs). In this sensing platform, the substrate peptide composed of kinase-specific recognized sequence and multiple positively charged arginine (R) residues was ingeniously designed. In the presence of protein kinase, the substrate peptide was phosphorylated and then immediately resisted CPY cleavage...
August 17, 2017: Analytical Chemistry
Anyi Chen, Min Zhao, Ying Zhuo, Yaqin Chai, Ruo Yuan
Although Ru(II)-complex-based bulk nanomaterials have received considerable attention in electrochemiluminescent (ECL) assays owing to their strong ECL signals, the ECL efficiency of these nanomaterials was quite low since the bulk nanomaterials brought about a serious inner filter effect and excess inactive emitters. Herein, hollow porous polymeric nanospheres of a self-enhanced ruthenium complex (abbreviated as Ru-HPNSs) were prepared with a polyethylenimine-ruthenium complex precursor to greatly decrease the inner filter effect and minimize inactive emitters, which significantly improved the ECL efficiency...
August 17, 2017: Analytical Chemistry
Wen-Chi Lin, Zhongrui Li, Mark A Burns
Leakage of lead and other heavy metals into drinking water is a significant health risk and one that is not easily detected. We have developed simple sensors containing only platinum electrodes for the detection of heavy metal contamination in drinking water. The two-electrode sensor can identify the existence of a variety of heavy metals in drinking water, and the four-electrode sensor can distinguish lead from other heavy metals in solution. No false-positive response is generated when the sensors are placed in simulated and actual tap water contaminated by heavy metals...
August 17, 2017: Analytical Chemistry
Ling Han, Luis C Morales, Michele R Richards, Elena N Kitova, Simonetta Sipione, John S Klassen
This work describes a versatile analytical approach, which combines the proxy ligand electrospray ionization mass spectrometry (ESI-MS) assay and model membranes of defined composition, to quantify the influence of lipid bilayer composition on protein-glycolipid binding in vitro. To illustrate the implementation of the assay (experimental design and data analysis), affinities of the monosialoganglioside ligand GM1, incorporated into nanodiscs (NDs), for cholera toxin B subunit homopentamer (CTB5) were measured...
August 17, 2017: Analytical Chemistry
Caroline W Karanja, Weili Hong, Waleed Younis, Hassan E Eldesouky, Mohamed N Seleem, Ji-Xin Cheng
Candida albicans (C. albicans) is the single most prevalent cause of fungal bloodstream infections worldwide causing significant mortality as high as fifty percent. This high mortality rate is, in part, due to the inability to initiate an effective antifungal therapy early in the disease process. Mortality rates significantly increase after twelve hours of delay in initiating the appropriate antifungal therapy following a positive blood culture. Early administration of appropriate antifungal therapy is hampered by the slow turnovers of the conventional antimicrobial testing techniques, which require days of incubation...
August 16, 2017: Analytical Chemistry
Amy Lynne Bondy, Rachel M Kirpes, Rachel Leah Merzel, Kerri A Pratt, Mark M Banaszak Holl, Andrew P Ault
Chemical analysis of atmospheric aerosols is an analytical challenge, as aerosol particles are complex chemical mixtures that can contain hundreds to thousands of species in attoliter volumes at the most abundant sizes in the atmosphere (~100 nm). These particles have global impacts on climate and health, but there are few methods available that combine imaging and the detailed molecular information from vibrational spectroscopy for individual particles <500 nm. Herein, we show the first application of atomic force microscopy with infrared spectroscopy (AFM-IR) to detect trace organic and inorganic species and probe intraparticle chemical variation in individual particles down to 150 nm...
August 16, 2017: Analytical Chemistry
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