Biodegradability and cell-mediated contraction of porous collagen scaffolds: the effect of lysine as a novel crosslinking bridge.

A novel crosslinking method was adopted to modify the porous collagen scaffolds by using a water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDAC) and N-hydroxysuccinimide (NHS) in the presence of lysine, which functions as a crosslinking bridge. In vitro biodegradation tests proved that in the presence of lysine the biostability of the EDAC crosslinked scaffolds was greatly enhanced. The biostability of the resultant scaffolds was also elucidated as a function of the concentrations of lysine and EDAC/NHS. Compared to the Col-DHT, the ability of the Col-EDAC and the Col/Lys to resist cell-mediated contraction (CMC) was greatly enhanced. Yet no obvious difference between the Col-EDAC and the Col/Lys was found with respect to CMC. SEM observations showed that the microstructure of the crosslinked scaffolds could be largely preserved after fibroblast seeding. As a result, MTT assays proved that the fibroblasts in the Col/Lys scaffolds proliferated faster compared to the DHT-treated one on the assumption that the cell viability was preserved to a similar level. Histological section results indicated that the Col/Lys scaffolds had the ability to accelerate the cell infiltration and proliferation. All these results demonstrated that this novel crosslinking method is an effective way to achieve a collagen scaffold with improved biostability and a more stable structure, which can resist cell-mediated contraction. (c) 2004 Wiley Periodicals, Inc. J Biomed Mater Res 71A: 334-342, 2004.