Adsorption of proteins to thin-films of PDMS and its effect on the adhesion of human endothelial cells

This paper describes a simple and inexpensive procedure to produce thin-films of poly(dimethylsiloxane). Such films were characterized by a variety of techniques (ellipsometry, nuclear magnetic resonance, atomic force microscopy, and goniometry) and used to investigate the adsorption kinetics of three model proteins (fibrinogen, collagen type-I, and bovine serum albumin) under different conditions. The information collected from the protein adsorption studies was then used to investigate the adhesion of human dermal microvascular endothelial cells. The results of these studies suggest that these films can be used to model the surface properties of microdevices fabricated with commercial PDMS. Moreover, the paper provides guidelines to efficiently attach cells in BioMEMS devices.Fil: Chumbimuni Torres, Karin Y.. The University of Texas at San Antonio; Estados UnidosFil: Coronado, Ramon E.. The University of Texas at San Antonio; Estados UnidosFil: Mfuh, Adelphe M.. The University of Texas at San Antonio; Estados UnidosFil: Castro Guerrero, Carlos. The University of Texas at San Antonio; Estados UnidosFil: Silva, María Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Biología Agrícola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza; ArgentinaFil: Negrete, George R.. The University of Texas at San Antonio; Estados UnidosFil: Bizios, Rena. The University of Texas at San Antonio; Estados UnidosFil: Garcia, Carlos D.. The University of Texas at San Antonio; Estados Unido

Visible Light-Induced Ion-Selective Optodes Based On A Metastable Photoacid For Cation Detection

A new platform of ion-selective optodes is presented here to detect cations under thermodynamic equilibrium via ratiometric analysis. This novel platform utilizes a \u27one of a kind\u27 visible light-induced metastable photoacid as a reference ion indicator to achieve activatable and controllable sensors. These ion-selective optodes were studied in terms of their stability, sensitivity, selectivity, and theoretical aspects

Nanomolar Detection Limits Of Cd\u3csup\u3e2+\u3c/sup\u3e, Ag\u3csup\u3e+\u3c/sup\u3e, And K \u3csup\u3e+\u3c/sup\u3e Using Paper-Strip Ion-Selective Electrodes

Paper-based ion-selective electrodes (ISEs) are simple, flexible, and cost-efficient in comparison to conventional solid-contact ISEs. Yet, paper-based ISEs have poor limits of detection (in the micromolar range) relative to conventional solid-contact ISEs. Here we describe the construction and optimization of ISEs based on commercially available filter paper modified with single-walled carbon nanotubes (SWCNTs), sputtered gold, and conductive polymer poly(3-octylthiophene) to support an ion-selective membrane. The ion-selective membrane presented here is based on the copolymer methyl methacrylate-decyl methacrylate (MMA-DMA). The copolymer MMA-DMA is highly water-repellent and has a low coefficient of diffusion, which makes it particularly suitable for the creation of sensors with high performance in reaching low limits of detection. Three different configurations of the electrodes have been characterized by using contact angle surface analysis, oxygen influence, and testing for the presence of a water layer. Paper-strip ISEs for cadmium, silver, and potassium ions were developed with groundbreaking limits of detection of 1.2, 25.1, and 11.0 nM, respectively. In addition to such low limits of detection, paper-strip ISEs display high selectivity for their ion of interest and high reproducibility. © 2014 American Chemical Society

Morphological Effect on the Surface Activity and Hydrogen Evolution Catalytic Performance of Cu₂O and Cu₂O/rGO Composites

Different cuprous oxide (Cu2O) particle forms, including the octahedron, truncated octahedron, cube, and star-like forms, are synthesized through chemical reduction under different reaction conditions. The correlation between the morphology and the catalytic activity of hydrogen evolution reactions (HERs) is investigated. It is discovered that the Cu2O particles with a higher 111/100 facets (r) ratio have a higher oxidation resistance and higher activity in HER catalysis, as supported by the density functional theory (DFT) calculation results. This improvement is attributed to the fact that more Cu+ terminated atoms on facet 111 provide more active sites, as measured using their electroactive area, as well as the lower H2 adsorption energy on that facet. To enhance Cu2O’s HER performance, cuprous oxide particles are deposited on reduced graphene oxide (rGO) through a hydrothermal method. XPS and XRD show a CuO layer on the composite surface, which reduces the Cu2O corrosion in the reaction. Overall, Cu2O/rGO composites exhibit a better particle distribution, increased active sites, and improved charge separation. The best electrocatalyst in this study is the Cu2O/rGO with a star-shaped form, with an overpotential of −458 mV. Its improved performance is attributed to the presence of unsaturated active sites with a higher reactivity, such as the edges and corners. SEM studies of this composite after catalysis indicate that Cu2O undergoes structural reconstruction during the reaction and reaches a more stable structure

Application Of Blind Source Separation Methods To Ion-Selective Electrode Arrays In Flow-Injection Analysis

As shown recently, the interference problem typical of ion-selective electrodes can be dealt with via smart arrays adjusted by blind source separation methods. In this letter, we resume this study and show that such an approach can be applied even when faced with a limited number of samples acquired through flow-injection analysis. © 2001-2012 IEEE

Ready-To-Use Single-Strip Paper Based Sensor For Multiplex Ion Detection

Ion-selective electrodes (ISEs) are an efficient and versatile tool for ion detection. However, portability and applicability for field applications are often limited by the need of a conditioning step, and high cost of the needed bulky reference electrode. Herein, the traditional conditioning protocol of ISEs has been eliminated and a paper-based solid-contact ISE (PBSC-ISE) has been integrated with a paper-based solid-contact reference electrode (PBSC-RE) in a single strip format for on-site analysis. The PBSC-RE is based on the copolymer methyl methacrylate-co-decyl methacrylate (MMA-DMA) (support matrix), combined with ionic liquids (ILs) to create and maintain a stable potential that is un-affected by a change in ionic activity. This single-strip ready-to-use sensor yields a Nernstian response towards Na+, K+, and I− ions with submicromolar limits of detection, and is able to be used for multiplex analysis