Physically-strengthened Collagen Bioactive Nanocomposite Gels for Bone: A Feasibility Study

Collagen hydrogel systems have been limited in their uses for hard tissue engineering due to their poor mechanical properties in spite of their excellent biocompatibility. Physical strengthening and incorporation of the inorganic substances are considered as promising ways to improve mechanical stability of the collagen gel, while providing effective biomimetic environment for cells. Here, we developed three-dimensional matrix by rolling up the plastically-compressed collagen hydrogel composites with mesoporous bioactive glass nanoparticle (BGn). Monodispersed BGn with a size of similar to 90 nm was well incorporated within the collagen matrix which has nanofibrillar structure. The mechanical properties of the composite hydrogels measured by dynamic mechanical analysis were significantly improved by the compression of the hydrogels and further improved by addition of BGn into hydrogels. Moreover, the proliferation rate and osteogenic differentiation of rat bone marrow derived mesenchymal stem cells cultured within the composite hydrogels were enhanced by incorporation of BGn. The results suggest that physically-strengthened nanocomposite collagen hydrogel would be useful in hard tissue engineering applications.