A review of digital microfluidics as portable platforms for lab-on a-chip applications

Lab Chip, 2016, Accepted ManuscriptDOI: 10.1039/C6LC00387G, Critical ReviewEhsan Samiei, Maryam Tabrizian, Mina HoorfarFollowing the development of microfluidic systems, there has been a high tendency towards developing lab-on-a-chip devices for bioche…

Oligonucleotide Based Label-free Detection with Optical Microresonators: Strategies and Challenges

Lab Chip, 2016, Accepted ManuscriptDOI: 10.1039/C6LC00521G, Critical ReviewPelin Toren, Erol Ozgur, Mehmet BayindirThis review targets diversified oligonucleotide based biodetection techniques, focusing on use of microresonators of whispering gallery m…

Personalized Nutrition Diagnostics at the Point-of-Need

Lab Chip, 2016, Accepted ManuscriptDOI: 10.1039/C6LC00393A, FrontierSeoho Lee, Balaji Srinivasan, Sasank Vemulapati, Saurabh Mehta , David EricksonMicronutrient deficiency is widespread and negatively impacts morbidity, mortality, and quality of life …

Microfluidic generation of hollow Ca-alginate microfibers

Lab Chip, 2016, Accepted ManuscriptDOI: 10.1039/C6LC00640J, PaperZhi-Jun Meng, Wei Wang, Rui Xie, Xiao-Jie Ju, Zhuang Liu, Liang-Yin ChuThis work reports on an efficient microfluidic approach for continuous production of hollow Ca-alginate microfibers …

Finger-powered Electrophoretic Transport OF Discrete Droplets For Portable Digital Microfluidics

Lab Chip, 2016, Accepted ManuscriptDOI: 10.1039/C6LC00219F, PaperCheng Peng, Yide Wang, Y. Sungtaek JuWe report a finger-powered digital microfluidics based on the electrophoretic transport of discrete droplets (EPD). An array of piezoelectric elements…

Biomimetic Spinning of Silk Fibers and in situ Cell Encapsulation

Lab Chip, 2016, Accepted ManuscriptDOI: 10.1039/C6LC00488A, PaperSang-Hoon Lee, Jie Cheng, DoYeun Park, Yesl Jun, JaeSeo Lee, Jinho HyunIn situ embedding of sensitive materials (e.g., cells and proteins) in silk fibers without damage presents a signifi…

A microdevice assisted approach for the preparation, characterization and selection of continuous aqueous two-phase systems: from micro to bench-scale

Lab Chip, 2016, Accepted ManuscriptDOI: 10.1039/C6LC00333H, PaperPatricia Vazquez-Villegas, Eric Ouellet, Claudia Gonzalez, Federico Ruiz-Ruiz, Marco Antonio Rito-Palomares, Charles Haynes, Oscar AguilarAqueous two-phase systems (ATPS) have emerged as…

Printing of stretchable silk membranes for strain measurements

Lab Chip, 2016, Advance ArticleDOI: 10.1039/C6LC00519E, PaperShengjie Ling, Qiang Zhang, David L. Kaplan, Fiorenzo Omenetto, Markus J. Buehler, Zhao QinA high stretchable silk strain gauge made by direct printing.To cite this article before page number…

Phenomenon of dual- and single-retention behaviors of solutes and its validation by computational simulation in linear programmed temperature gas chromatography

The current theory of programmed temperature gas chromatography considers that solutes are focused by the stationary phase at the column head completely and does not explicitly recognize the different effects of initial temperature (To) and heating rate (rT) on the retention time or temperature of a homologue series. In the present study, n-alkanes, 1-alkenes, 1-alkyl alcohols, alkyl benzenes and fatty acid methyl esters standards were used as model chemicals and were separated on two non-polar columns, one middle polar column and one polar column. Retention behaviors of the non-stationary phase focusing and stationary phase focusing solutes can be explicitly described with isothermal and cubic equation models, respectively. When the solutes were in the non-stationary phase focusing status, the dual retention behaviors of solutes were observed. Dual retention behaviors are complicated, sensitive to temperature changes from both To and rT values and cannot be described by any explicit expression. When the solutes were in the stationary phase focusing status, the single-retention behavior of solutes was observed. It is simple, dependent upon rT only and can be well described by the cubic equation model which was visualized through four sequential slope analyses. These observed dual- and single-retention behaviors of solutes were validated by various experimental data, physical properties and computational simulation.
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Spectroscopic Ellipsometry as a Complementary Tool to Characterize Coatings on PDMS for CE Applications

This paper describes the use of spectroscopic ellipsometry to investigate the adsorption process of model polyelectrolytes (PDDAC and PSS) to thin-films of PDMS. A description of the information collected by ellipsometry as well as complementary information obtained by atomic force microscopy and contact angle measurements is discussed. Upon identification of the driving forces and optimum experimental conditions required for the adsorption, multilayer constructs were fabricated (ranging from 1 to 20 nm in thickness) and used to evaluate their effect on the separation of phenolic compounds by capillary electrophoresis. According to the presented results, polyelectrolyte layers of approximately 10 nm thick provided the best conditions for the separation of the selected phenolic compounds.
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Microfluidic free-flow zone electrophoresis and isotachophoresis using carbon black nano-composite PDMS sidewall membranes

We present a new type of free-flow electrophoresis (FFE) device for performing on-chip microfluidic isotachophoresis (ITP) and zone electrophoresis (ZE). FFE is performed using metal gallium electrodes, which are isolated from a main microfluidic flow…

Analytical and semipreparative chiral separation of cis-itraconazole on cellulose stationary phases by high-performance liquid chromatography

cis-Itraconazole is a chiral antifungal drug administered as a racemate. The knowledge of properties of individual cis-itraconazole stereoisomers is vital information for medicine and biosciences as different stereoisomers of cis-itraconazole may poss…

Screening and identification of hepatotoxic component in Evodia rutaecarpa based on spectrum-effect relationship and UPLC-Q-TOFMS

Evodia rutaecarpa (E. rutaecarpa) has been used to treat aches, vomiting and dysentery in traditional Chinese medicine. However, as a mild toxic herb its toxic components have not been elucidated. An attempt was made to illuminate the hepatotoxic constituents of E. rutaecarpa. The 50% ethanol extracts of E. rutaecarpa from 19 different sources were used to establish UPLC fingerprints and administered to mice at a dose of 35 g/kg (crude medicine weight/mouse weight) once daily for 14 days. Serum levels of alanine transaminase (ALT), aspartate aminotransferase (AST) and liver coefficient were used as indices of liver injury. Additionally, the characteristic peaks of 19 fingerprints were identified. Spectrum-effect relationship between fingerprints and hepatotoxic indicators were analyzed using Bivariate correlation analysis (BCA). The UPLC fingerprints were established and a total of 28 main compounds were identified. Because of the inherent variations in chemical compositions, the liver injury levels were different among the E. rutaecarpa samples from 19 production place. BCA results indicated that compounds Dihydrorutaecarpine, 6-acetoxy-5-epilimonin, Goshuyuamide I, 1-Methyl-2-[(Z)-5-undecenyl]-4(1H)-quinolone, 1-Methyl-2-[(4Z,7Z)-4,7-tridecadienyl]-4(1H)-quinolone, Evocarpine and 1-Methyl-2-[(6Z,9Z)-6,9-pentadecadienyl]-4(1H)-quinolone were tentatively determined as the primary hepatotoxic components. The present study provides a valuable method for the discovery of hepatotoxic constituents by combination of fingerprints and hepatotoxicity index.

Development of simultaneous analysis of tryptophan metabolites in serum and gastric juice – an investigation towards establishing a biomarker test for gastric cancer diagnosis

To evaluate changes in tryptophan metabolism and discover diagnostic biomarkers for gastric cancer, a quantitative method was developed for tryptophan and its seven metabolites (indole-3-lactic acid, anthranilic acid, serotonin, nicotinic acid, kynurenic acid, kynurenine, and 3-indoxyl sulfate) in both human serum and gastric juice using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Serum and gastric juice were prepared with a simple protein precipitation using aqueous 0.1% formic acid and acetonitrile. As a result, it was found that the kynurenine pathway of tryptophan metabolism was activated in gastric cancer and that the metabolic ratio of kynurenine/tryptophan, which reflects the enzyme activity of indoleamine-2,3-dioxygenase (IDO), was associated with the observed metabolic changes. Finally, the investigation of tryptophan metabolites, especially kynurenic acid, in serum and gastric juice might serve as biomarkers for gastric cancer. The findings in this study provide critical information of tryptophan metabolism which can be applied to a serum-based diagnostic test for gastric cancer.

Analysis of Nerve Agent Metabolites from Hair for Long-Term Verification of Nerve Agent Exposure

Analytical ChemistryDOI: 10.1021/acs.analchem.6b01274

Anesthetic constituents of Zanthoxylum bungeanum Maxim. pharmacokinetic study

A sensitive and selective ultra high performance liquid chromatography with tandem mass spectrometry method was established and validated for the simultaneous determination of hydroxy-α-sanshool, hydroxy-β-sanshool and hydroxy-γ-sanshool in rat pla…

Determination of hexabromocyclododecane enantiomers in chicken whole blood by a modified quick, easy, cheap, effective, rugged, and safe method with liquid chromatography and tandem mass spectrometry

A rapid and simple analytical method has been developed for the determination of hexabromocyclododecane enantiomers in chicken whole blood, based on a modified quick, easy, cheap, effective, rugged and safe approach before liquid chromatography couple…

Ultra-Trace Analysis of Furanic Compounds in Transformer/Rectifier Oils with Water Extraction and high-performance liquid chromatography

A novel approach for the determination of parts-per-billion level of 5-hydroxymethyl-2-furaldehyde, furfuryl alcohol, furfural, 2-furyl methyl ketone, and 5-methylfurfural in transformer or rectifier oils has been successfully innovated and implemented. Various extraction methods including solid-phase extraction, liquid–liquid extraction using methanol, acetonitrile, and water were studied. Water was found to be by far the most practical and reliable solvent for use as an extraction medium. Separation of the analytes of interest was conducted using a 4.6 mm × 250 mm × 3.5 μm Agilent Zorbax column while the detection and quantitation of targeted analytes were conducted with a variable wavelength UV detector. Detection limits of all furans were found to be at 1 ppb v/v with linear ranges range from 5 to 1000 ppb v/v with correlation coefficients of at least 0.997 or better. A relative standard deviation of at most 2.4% at 1000 ppb v/v and 7.3% at 5 ppb v/v and a recovery of greater than 98% for all compounds were obtained. The method was purposely designed as a greener chemistry approach with water being used as an extraction medium since water is accessible in practically anywhere around the world. Also, the method uses 80% water and 20% acetonitrile with a mere 0.2 mL/min of acetonitrile in an acetonitrile/water mixture as mobile phase. The analytical technique has been demonstrated to be highly reliable with low cost of ownership, suitable for deployment in quality control labs or in regions where available analytical resources and solvents are difficult to procure.
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Selective adsorption of protein by a high-efficiency Cu2+-cooperated magnetic imprinted nanomaterial

We report a core–shell magnetic molecularly imprinted polymer with high affinity through a facile sol–gel method for selective adsorption of bovine hemoglobin from real bovine blood. Copper ions grafted on the surface of matrix could immobilize template protein through chelation, which greatly enhances the orderliness of imprinted cavities and affinity of polymers. The obtained products exhibit a desired level of magnetic susceptibility, resulting in the highly efficient adsorption process. The results of adsorption experiments show that the saturation adsorption capacity of imprinted products could reach 116.3 mg g−1 within 30 min. Meanwhile, the specific binding experiment demonstrates the high selectivity of polymers for bovine hemoglobin. Furthermore, satisfactory reusability is demonstrated by ten adsorption–desorption cycles with no obvious deterioration in binding capacity. Electrophoretic analysis suggests the polymer could be used successfully in separation and enrichment of bovine hemoglobin from the bovine blood sample, which exhibits potential application in pretreatment of proteomics.
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New strategy for the biosorption of atrazine after magnetic solid phase extraction from water followed by high-performance liquid chromatography analysis

We describe a rapid and simple microextraction of atrazine from water samples. This method is based on the use of magnetic nanoparticles as sorbents and bioaggregates that are applied to the extraction and preconcentration of atrazine. The resulting m…