Improved calcification resistance and biocompatibility of tissue patch grafted with sulfonated PEO or heparin after glutaraldehyde fixation

A novel chemical modification of biological tissues was developed aimed at improving biocompatibility and calcification resistance. This method involv ed the additional grafting of sulfonated PEG (PEO-SO3,) or heparin after co nventional glutaraldehyde (GA) fixation of bovine pericardium (BP). The ami no groups of PEG-SO, or heparin were utilized to react to the GA residues t o block them. The PEG-SO, or heparin grafted tissues demonstrated a slightl y higher shrinkage temperature and tensile strength, but greater resistance to collagenase digestion, than GA treated ones. These results suggest that modified tissues have improved durability due to the grafting and filling effect of PEG-SO, or heparin in addition to the GA cross-linking, At the di rect contact cytotoxicity test in vitro, PEG-SO, or heparin grafted tissue was shown to be nontoxic, while relatively significant cytotoxicity was obs erved for the GA treated tissues, possibly due to the release of GA, From t he in vivo calcification study, calcium contents deposited on the modified tissues were much less than those on GA treated tissues. Such a decreased c alcification might be explained hy the decrease of residual GA groups durin g the additional treatment, and the space-filling effect and the nonadhesiv e property and/or the blood compatiblility of PEG-SO, or heparin grafted co valently, The newly modified tissue patch was observed to show improved pat hological assessibility including less inflammation and tissue reactions, T his simple modification method may be useful for calcification-resistant an d blood-compatible tissue patches for cardiovascular implants. (C) 2000 Joh n Wiley & Sons. Inc. J Biomed Mater Res (Appl Biomater) 58: 27-35. 2001.