Surface coupling of long-chain hyaluronan to the fibrils of reconstituted type II collagen

The aim of this study was to fabricate type II collagen fibrils with surface modified by long-chain hyaluronic acid. Monomeric type II collagen was isolated from bovine articular cartilage and reconstituted into collagen fibrils followed by a reaction with EDC (1-Ethyl-3-[3-dimethylaminopropyl] carbodiimide)-activated long-chain hyaluronic acid. The existence of the hyaluronan molecules on the fibrillar surface was confirmed by the specific bindings of gold nanoparticles labeled with wheat germ agglutinin. The topographic pattern of type II collagen fibrils revealed by AFM scanning changed significantly after the surface coupling of hyaluronic acid. Beneath the hyaluronan, the characteristic D-bandings of the reconstituted collagen fibrils remained intact as shown by the results of TEM observation. The collagen fibrils became more resistant to collagenase digestion after surface coupling of hyaluronic acid as compared with that without hyaluronic acid immobilization. In addition, human mesenchymal stem cells encapsulated and cultured within the matrix of HA-collagen fibrils have a higher proliferation rate than cells grown within the unmodified type II collagen fibrils. The newly synthesized material of HA-collagen II fibrils has a great potential for use in constructing scaffold for tissue repair.