Adsorption of plasma proteins to DMAA hydrogels obtained by ionizing radiation and its relationship with blood compatibility

The interaction of plasma proteins such as albumin, gamma-globulin, and fibrinogen with the surface of graft copolymers DMAA-G-PTFE, DMAA-G-PETFE, and DMPLA-G-PE obtained by radiation graft polymerization was studied. The adsorption of serum proteins was affected by the hydrophilicity of the graft copolymers. Increased albumin adsorption and decreased fibrinogen and gamma-globulin adsorption with increasing grafting levels was shown. A certain range of degrees of grafting showed an improved blood compatibility of the polymeric surfaces due to the existence of a hydrophilic/hydrophobic balance on the polymers. The results suggest that the DMAA-G-PTFE, DMAA-G-PETFE, and DMAA-G-FE graft copolymers can be used as biomaterials for longterm use in cardiovascular systems.8533534

Scaffolds of poly (epsilon-caprolactone) with whiskers of hydroxyapatite

Scaffolds of Poly (epsilon-caprolactone)/hydroxyapatite were produced and studied for tissue engineering applications. The materials were selected due to its biodegradability (PCL) and bioactivity (HA), and above all their biocompatibility toward the human tissue. The composites produced were characterized by SEM, XRD, and EDS. By analyzing these characterizations it was possible to obtain further information about the composition and morphology aspects of all portions of the composite scaffold.45184990499

Poly (acryloyl-l-proline methyl ester) hydrogels obtained by radiation polymerization for the controlled release of drugs

Thermosensitive hydrogels were obtained by radiation-induced polymerization of acryloyl-L-proline methyl ester in the presence of a crosslinking agent. The measurements of equilibrium water content in the temperature range between 08 and 608C showed that the samples swelled at low temperatures while they shrank at high temperatures. These hydrogels were used as drug delivery systems for the controlled release of insulin. In vivo studies carried out on diabetic rats ascertained a signi®cant reduction in the hyperglycemic level in the blood which continued for about 2 months. # 2000 Elsevier Science Ltd. All rights reserved

alpha-tricalcium phosphate cement: 'in vitro' cytotoxicity

Calcium phosphate-based bioceramics have revolutionized orthopedic and dental repair of damaged parts of the bone system. Among these materials, calcium phosphate-based cements, with hydraulic setting, stand out due to their biocompatibility and in situ hardening, which allow easy manipulation and adaptation to the shape and dimensions of bone defects. An investigation was made of the in vitro cytotoxic effect of calcium phosphate cement based on a-tricalcium phosphate, immersed for different lengths of time in simulated body fluid (SBF), based on the ISO-10993 'Biological Evaluation of Medical Devices' standard. The culture medium was Chinese hamster ovary (CHO) cells in contact with diluted cement extracts. The results revealed that the calcium phosphate cement used was cytotoxic and that the material's cytotoxicity decreased the longer the cement was immersed in SBF. (C) 2002 Elsevier Science Ltd. All rights reserved.2392035204

Glycerin and Ethanol as Additives on Silk Fibroin Films: Insoluble and Malleable Films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Silk fibroin (SF) films have been largely studied as biomaterials due to their biocompatibility and biodegradability. Casting a SF aqueous solution at room temperature is a common technique to produce SF films at relative low cost and processing time; however, their brittleness and solubility in water make them unsuitable for certain biomedical applications. In this study, the incorporation of additives, ethanol and glycerin, are presented as an alternative to both improve mechanical properties of SF films and decrease their solubility in water. SF films with additives were further characterized using scanning electron microscopy, X-ray diffraction, Fourier transformed infrared spectroscopy with attenuated total reflection, analysis of water solubility, mechanical test of traction, and in vitro cytotoxicity experiments. The results show that SF films containing additives are stable in water due to the effect of glycerin and ethanol, and do not require post-treatments. Furthermore, great improvements on elongation of the films were achieved, mainly in the presence of both additives. In addition, all films were not toxic to cells, which is a first indication of their biocompatibility. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 128: 115-122, 20131281115122Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Inhibition of calcification of bovine pericardium after treatment with biopolymers, E-beam irradiation and in vitro endothelization

This work has investigated the in vitro calcification of bovine pericardium (BP) treated with chitosan (C), silk fibroin (SF) and electron beam irradiation after its endothelization in vitro. For this purpose, freeze-dried BP membranes treated with mixtures of C and SF (1:3, 1:1 and 3:1) and then irradiated by electron beam irradiation were seeded with human umbilical vein endothelial cells (HUVEC) in vitro. After 3 weeks of cultivation these membranes were submitted to in vitro calcification tests using simulated body fluid as the calcifying agent. Control membranes were also studied (without endothelial cells exposure). The results have shown that the membrane compatibility with HUVECs in vitro prevent such biomaterial from calcifying, showing a potential application in biomaterial area, such as cardiac valves and repair patches. (c) 2012 Elsevier B.V. All rights reserved.331859

Glutaraldehyde-treated bovine pericardium: Effects of lyophilization on cytotoxicity and residual aldehydes

This work assesses the effect of lyophilization on the cytotoxicity and residual aldehyde concentra- tion of glutaraldehyde-treated and lyophilized bovine pericardium (group A), comparing it to conventional glutaraldehyde-treated bovine pericardium (group B). Cytotoxicity was measured by incubating a pericardium sample from each group in saline and assessing the eluant's influence on cellular growth. Residual aldehydes were measured by HPLC. Although both groups' eluants exhibited some cytotoxicity, the eluant from group A was less cytotoxic, with a cytotoxicity index (IC(50(%)) ) of 41%. Group B eluants all had marked cytotoxic effects; cell growth was 24.15% of the negative control at the most dilute eluant concentration (6.25%). The mean residual glutaraldehyde level was less in group A than in group B (2.36 +/- 0.11 and 9.90 +/- 3.70 g/l, respectively; n=3, P < 0.05), but residual formaldehyde levels did not differ. These results demonstrate that compared with conventional glutaraldehyde-treated bovine pericardium, lyophilized pericardium is less cytotoxic, with fewer glutaraldehyde residues.27869269

Lyophilized bovine pericardium treated with a phenethylamine-diepoxide as an alternative to preventing calcification of cardiovascular bioprosthesis: Preliminary calcification results

This study investigated the calcification process that occurred on chemically treated bovine pericardium substrata through tests with simulated body fluid solutions. The use of bovine pericardium bioprosthetic valves in heart valve surgery has a significant drawback due to the calcification processes. Thus, many routes such as chemical treatments in the substratum or the adoption of systemic therapies are considered in the literature with the intention to inhibit or to decelerate this process. The presented treatment using the two different phenetylamine-diepoxide solutions showed no effects on calcification experiments as showed by the tests. However, the lyophilized bovine pericardium samples, treated with both solutions, did not show any detectable phosphate deposits. The lyophilization of bovine pericardium before chemical treatments with cross-link agents as epoxy compounds may be an alternative to the conventional calcification prevention methods, but further investigations are recommended to check if the same behavior is found in all lyophilized systems.31427828