Poly(2-hydroxyethylmethacrylate) (PHEMA) microbeads prepared by suspension polymerization were treated with diamine-plasmas (i.e. ethylene-diamine (EDA) and hexamethylene diamine (HMDA)) in a glow-discharge reactor in which the exposure time and glow-discharge power were changed between 5 and 30 min and 5 and 20 W, respectively. The amount of nitrogen deposition increased both with increase in exposure time and glow-discharge power. The maximum amounts of nitrogen deposition on the microbeads were 22.3 and 23.4 micromol g(-1) with the EDA- and HMDA-plasmas. Then, Cu(II) ions were incorporated onto the PHEMA microbeads by chelating with the nitrogen-carrying functional groups. Different amounts of Cu(II) ions (2.4-6.8 mg g(-1)) were incorporated on the PHEMA microbeads by changing the initial concentration of Cu(II) ions. Bovine serum albumin (BSA) adsorption onto the unmodified PHEMA, diamine-plasma treated PHEMA, and diamine-plasma treated Cu(II)-incorporated PHEMA microbeads was investigated. The non-specific adsorption of BSA on the unmodified microbeads was very low (0.22 mg BSA g(-1)). Deposition of nitrogen increased the BSA adsorption (9.3 mg g(-1) for EDA-plasma and 12.7 mg g(-1) for HMDA-plasma). Cu(II)-incorporation significantly increased the BSA adsorption (154 mg g(-1) for EDA-plasma and 178 mg g(-1) for HMDA-plasma). Further increases in the albumin adsorption capacities of the polymer microbeads (185 mg g(-1) for EDA-plasma and 208 mg g(-1) for HMDA-plasma) were observed when human plasma was used. More than 92% of the adsorbed albumin molecules was desorbed in 1 h in the desorption medium containing 0.5 M NaSCN at pH 8.0. Repeated adsorption-desorption cycles showed the feasibility of these plasma-modified polymer microbeads.
Medical devices made of polycarbonates are generally sterilized by ionizing radiation. The effect of irradiation on the response of polycarbonate to various components of body fluids was studied in this work. Polycarbonate films prepared by solvent casting technique from various solvents were gamma-irradiated in the range of 0-200 kGy. Characterizations of the films were achieved by contact angle and water-uptake studies as well as atomic force microscope (AFM) images. It was found that gamma-irradiated films were more hydrophilic than unmodified films. AFM images showed that surface roughness increased with gamma irradiation. Protein adsorption experiments conducted with human plasma demonstrated that protein adsorptions drastically increased by increasing the applied irradiation dose. The unirradiated and gamma-irradiated films were contacted with human blood in in vitro systems. Loss of the blood cells and clotting times were followed. Loss of blood cells in the plasma contacting with gamma-irradiated films was negligible. Any significant change was also followed for clotting times with gamma-radiation dose.
Bioaffinity adsorption has a unique and powerful role as a support tool in the removal of toxic substances from human plasma. Synthetic hollow-fiber membranes have advantages as support matrices in comparison to conventional hemoperfusion columns because they are not compressible and they eliminate internal diffusion limitations. In this study, Cibacron Blue F3GA was covalently attached onto commercially available microporous polyamide hollow-fiber membranes for bilirubin removal from hyperbilirubinemic human plasma. Different amounts of Cibacron Blue F3GA were attached on the polyamide hollow-fibers by changing the dye-attachment conditions, i.e., initial dye concentration, addition of sodium carbonate, and sodium chloride. 1989
The aim of this study is to investigate the usability of cryogel columns for the purification of invertase from Saccharomyces cerevisiae. Poly(2-hydroxyethyl methacrylate) monolithic columns were produced via cryogelation. Ester groups of the poly(2-hydroxyethyl methacrylate) structure were then converted to imine groups by the reaction with poly(ethylene imine) in the presence of NaHCO. Transition metal ions, Cu(II), Co(II), and Ni(II), were chelated on the PEI-modified cryogel columns. Purification of invertase from natural source namely S. cerevisiae was also studied, and the purification fold values were obtained as 41.350, 44.714, and 30.302 for Cu(II)-chelated, Co(II)-chelated, and Ni(II)-chelated PHEMA/PEI columns, respectively.
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