Effect of Freezing and Thawing on Uptake of Amino Acids into Human Erythrocytes

ABSTRACT - The transport of C-amino acids into human erythrocytes and into erythrocytes which had been frozen and thawed was studied experimentally. The relative rates of uptake were found to be (in decreasing order): phenylalanine, leucine, alanine, trythophan, and glycine. Freezing (using gycerol as the cryoprotective additive) and thawing had no significant effect on either the magnitude of the rate constants or on the order of the above relative rates of amino acid uptake into erythrocytes suspended in isotonic TRIS-HCl buffer

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

An Introduction To Tissue-Biomaterial Interactions

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Electrochemically-Preadsorbed Collagen Promotes Adult Human Mesenchymal Stem Cell Adhesion on Carbon Nanostructured Substrates

The effect of electric potential on the adsorption of collagen type I onto optically transparent carbon electrodes (OTCE) and its mediation on subsequent adhesion of adult, human, mesenchymal stem cells (hMSCs) is described. Adsorption was investigated as a function of the protein concentration and applied potential. The resulting substrate surfaces were characterized using spectroscopic ellipsometry (SE), atomic force microscopy (AFM), and cyclic voltammetry (CV). While the higher applied potential and protein concentration, the higher the adsorbed amount, the application of potential values higher than +800 mV resulted in the oxidation of the adsorbed protein. Subsequent adhesion of hMSCs on the substrates under standard cell culture conditions was also affected by the potential applied and when the collagen type I was oxidized (under applied potential \u3e +800 mV), hMSCs adhesion was decreased. These results provide the first correlation between the effects of electric potential on protein adsorption and subsequent modulation of anchorage-dependent cell adhesion