Poly (hydroxyethyl methacrylate-glycidyl methacrylate) films modified with different functional groups: In vitro interactions with platelets and rat stem cells

Copolymerization of 2-hydroxyethylmethacrylate (HEMA) with glycidylmethacrylate (GMA) in the presence of α-α′- azoisobisbutyronitrile (AIBN) resulted in the formation of hydrogel films carrying reactive epoxy groups. Thirteen kinds of different molecules with pendant NH2 group were used for modifications of the p(HEMA-GMA) films. The NH2 group served as anchor binding site for immobilization of functional groups on the hydrogel film via direct epoxy ring opening reaction. The modified hydrogel films were characterized by FTIR, and contact angle studies. In addition, mechanical properties of the hydrogel films were studied, and modified hydrogel films showed improved mechanical properties compared with the non-modified film, but they are less elastic than the non-modified film. The biological activities of these films such as platelet adhesion, red blood cells hemolysis, and swelling behavior were studied. The effect of modified hydrogel films, including NH2, (using different aliphatic CH2 chain lengths) CH3, SO3H, aromatic groups with substituted OH and COOH groups, and amino acids were also investigated on the adhesion, morphology and survival of rat mesenchymal stem cells (MSCs). The MTT colorimetric assay reveals that the p(HEMA-GMA)-GA-AB, p(HEMA-GMA)-GA-Phe, p(HEMA-GMA)-GA-Trp, p(HEMA-GMA)-GA-Glu formulations have an excellent biocompatibility to promote the cell adhesion and growth. We anticipate that the fabricated p(HEMA-GMA) based hydrogel films with controllable surface chemistry and good stable swelling ratio may find extensive applications in future development of tissue engineering scaffold materials, and in various biotechnological areas. © 2012 Elsevier B.V

Affinity dye-ligand poly(hydroxyethyl methacrylate)/chitosan composite membrane for adsorption lysozyme and kinetic properties (Letter)

[No abstract available

Polyethylenimine-grafted and HSA-immobilized poly(GMA-MMA) affinity adsorbents for bilirubin removal

The epoxy-group-containing microspheres from cross-linked glycidyl methacrylate and methyl methacrylate, poly(GAM-MMA), were prepared by suspension polymerisation. The epoxy groups of the poly(GMA-MMA) microspheres were used for grafting with an anionic polymer polyethylenimine (PEI) to prepare non-specific affinity adsorbents (poly(GMA-MMA)-PEI) for bilirubin removal. The specificity of the poly(GMA-MMA)-PEI adsorbent to bilirubin was further increased by immobilization of human serum albumin (HSA) via adsorption onto PEI-grafted poly(GMA-MMA) adsorbent. Various amounts of HSA were immobilized on the poly(GMA-MMA)-PEI adsorbent by changing the medium pH and initial HSA concentration. The maximum HSA content was obtained at 68.3mg g-1 microspheres. The effects of pH, ionic strength, temperature and initial bilirubin concentration on the adsorption capacity of both adsorbents were investigated in a batch system. Separation of bilirubin from human serum was also investigated in a continuous-flow system. The bilirubin adsorption on the poly(GMA-MMA)-PEI and poly(GMA-MMA)-PEI-HSA was not well described by the Langmuir model, but obeyed the Freundlich isotherm model. The poly(GMA-MMA)-PEI affinity microspheres are stable when subjected to sanitization with sodium hydroxide after repeated adsorption-desorption cycles. © 2004 Society of Chemical Industry

Characterization of β-galactosidase immobilized into poly(hydroxyethyl methacrylate) membranes

β-galactosidase was immobilized into pHEMA membranes with the highest specific activity yield of 9.5%. The specific activity of the entrapped enzyme was found to be decreased as the enzyme loading increased in pHEMA membranes. The optimum pH and temperature for maximum activity of the immobilized βgalactosidase was found to be at pH 7.5 and 50°C, respectively, and were the same as native enzyme. K(m) and V(max) values for the free enzyme were found to be 0.256 mM and 26.6 μmole/min/mg, respectively. K(m) value of immobilized βgalactosidase was found to be increased about 3 folds upon immobilization. Operational, thermal and storage stability of β-galactosidase were found to increase with immobilization. Immobilized enzyme preparation was reused in 15 cycles without significant loss in activity

Low-molecular-weight heparin-conjugated liposomes with improved stability and hemocompatibility

Multilamellar vesicles (MLV) containing phosphatidyl choline (PC), cholestrol (CHOL), and stearylamine (SA) in the molar ratio of 7:2:0.2 were prepared by the thin film hydration method. Low-molecular-weight heparin (LMWH, MW: 3000) was conjugated with the MLV using carbodiimide (EDC). Infrared, Raman, and nuclear magnetic resonance spectra and DSC of each sample (MLV, LMWH, and MLV-LMWH) were obtained, enabling the authors to determine the chemical changes that occurred in the MLV structure at the end of the conjugation step. In addition, the changes in the chemical structures of the conjugated samples were revealed by the use of elemental analysis. Particle size analysis was used to determine the difference between the sizes of MLV and MLV-LMWH. In order to study the effect of LMWH on the behavior of MLV-LMWH in blood, osmotic fragility (in saline and plasma), hemolytic activity, and plasma recalcification time tests were carried out. These tests showed that it was possible to construct liposomes that would not induce reactions in the blood and would have potentially longer half-lives in the circulation

Aminopyridine Modified Spirulina Platensis Biomass For Chromium(Vi) Adsorption In Aqueous Solution

Scopu

Construction of a bioraactor for the degradation of the pesticide, aldicarb

Water soluble derivatives of cellulose are widely used in various biomedical and biotechnological applications. Sodium carboxymethyl cellulose (25 ml, 1-4% w/v) was insolubilized in the form of microspheres using aluminum chloride (150 ml, 0.2-2.0 M) as the crosslinking agent. Microspheres were activated by epichlorohydrin. Methylophilus, a Gram negative bacteria capable of degrading aldicarb, a carbamate pesticide, was immobilized Methylophilus was determined by feeding in aqueous aldicarb solutions (10-400 ppm) at a rate of 20 ml/h. The degradative capability was found to be quite stable for ca. 48 h, and ca. 10% of the aldicarb was degradative capability was found to be quite stable for ca. 48 h, and ca. 10% of the aldicarb was found to be metabolized in the packed bed approach with a single pass application. © 1997 Elsevier B.V. All rights reserved.Consejo Nacional de Investigaciones Científicas y Técnicas: TBAG-DPT-27 Orta Doğu Teknik ÜniversitesiThe authors appreciate the support by the Scientific and Technical Research Council of Turkey (Grant No: TBAG-DPT-27) and by the Middle East Technical University, Graduate School of Natural and Applied Sciences (assistantship to F.N.K.)