Effect of alternative crosslinking techniques on the enzymatic degradation of bovine pericardia and their calcification

Abstract

The in vitro calcification and enzymatic degradation of bovine pericardia (BP) after a series of surface treatments were studied as a function of exposure time. The degradation of these treated surfaces was monitored by scanning electron micrography and tensile strength measurements. Polyethylene glycol-(PEG) grafted BP and glutaraldehyde-(GA) treated BPs retained maximum stability in collagenase digestion compared with SDS-treated BP. The ability of alpha chymotrypsin, bromelain, esterase, trypsin, and collagenase to modulate the degradation of SDS-, GA-, PEG-, Carbodiimide-, and glycidylether-treated BPs also was investigated. Incubation of various enzymes to these crosslinked pericardia variably reduced the tensile strength of these tissues. It is conceivable that chemical treatments of pericardial tissues might have altered their physical and chemical configuration and the subsequent degradation properties. In vitro calcification studies showed a substantial reduction in the calcification profile of PEG-grafted bovine pericardia compared to other treated tissues. Furthermore, the biocompatibility aspects of pericardial tissues were established by platelet adhesion and octane contact angle. In conclusion, it seems that the surface modification of bovine pericardia via GA-PEG grafting may provide new ways of controlling biodegradation and calcification.

Kinetic characterization and comparison of various protein crosslinking reagents for matrix modification

“…We therefore monitored crosslink formation indirectly using a collagenase protection assay which has been commonly used for this purpose previously [10, 45–48]. This method, however, may underestimate the number of crosslinks formed since it is possible that complete protease protection might be achieved before reaction of every possible crosslinking site.…”

A structural constitutive model for chemically treated planar tissues under biaxial loading

“…However, due to the aforementioned calci®cation and structural durability problems, both PAV and BP BHV are limited to patients 65 years or older, substantially limiting their applicability. There have been many attempts to improve BP use through novel chemical treatments (Harasaki et al, 1990;Pereira et al, 1990;Petite et al, 1990;Vasudev and Chandy 1997). An example of the dif®culties in extending the BHV durability underscored by a recently developed chemical treatment technology, dye-mediated photooxidation.…”

Preparation of Surface-Engineered Elastin/Lamin Nerve Guide Tubes of Poly(Lactic Acid)/Poly(Ethylene Vinyl Acetate)

“…The tubes were removed at specific time periods, washed thoroughly with distilled water and dried for several hours under vacuum. The degradation of the polymers was checked by gravimetric methods [17,18]. Hydrolytic degradation of the tubes was also monitored by immersing them in 0.1M PBS pH 7.4 and pH 8.4 in a similar fashion.…”