Chitosan modified poly(glycidyl methacrylate¯butyl acrylate) copolymer grafted bovine pericardial tissue¯¯anticalcification properties

Calcification is the main cause of failure of glutaraldehyde crosslinked pericardial tissue used as heart valve substitutes. In our earlier work, we have shown that the grafting of glutaraldehyde crosslinked pericardial tissue with poly[glycidylmethacrylate(GMA) ¯butyl acrylate(BA)] copolymer with monomer ratio of 15:7.2 resulted in 50% reduction in calcification. In the present investigation, an attempt was made to eliminate calcification of the polymer grafted glutaraldehyde crosslinked pericardial tissue by coupling with low molecular weight chitosan. Low molecular weight chitosan was prepared to improve its solubility in water containing lower concentration of acetic acid and ensure easy diffusion into the tissue fiber matrix. The effect of treatment with the prepared chitosan on the anticalcification properties of poly(GMA¯BA) copolymer grafted pericardial tissue was studied. It was found that chitosan post treatment of copolymer grafted glutaraldehyde crosslinked pericardial tissue was able to reduce the susceptibility of the glutaraldehyde crosslinked pericardial tissue to negligible levels after 30 days of implantation in rat subcutaneous models.