POROSITY AND BIOLOGICAL PROPERTIES OF POLYETHYLENE GLYCOL-CONJUGATED COLLAGEN MATERIALS

Collagen-based materials can be designed for use as scaffolds for conn ective tissue reconstruction. The goal of the present study was to eva luate the behavior of collagen materials as well as cell and tissue re actions after the conjugation of activated polyethylene glycols (PEGs) with collagen. It is known that proteins conjugated with PEGs exhibit a decrease in their biodegradation rate and their immunogenicity. Dif ferent concentrations and molecular weights of activated PEGs (PEG-750 and PEG-5000) were conjugated to collagen materials (films or sponges ) which were then investigated by collagenase assay, fibroblast cell c ulture, and subcutaneous implantation. PEG-conjugated collagen sponge degradation by collagenase was delayed in comparison to untreated spon ges. In culture, fibroblasts with a normal morphology reached confluen cy on PEG-conjugated collagen films. In vivo, the porous structure of non-modified sponges collapsed by day 15 with a few observable fibrobl asts between the collagen fibers. In PEG-modified collagen sponges, th e porous structure remained stable for 30 days. Cell infiltration was particularly enhanced in PEG-750-conjugated collagen sponges. In concl usion, PEGs conjugated onto collagen sponges stabilize the porous stru cture without deactivating the biological properties of collagen. Thes e porous composite materials could function as a scaffold to organize tissue ingrowth.