An osteoconductive collagen/hyaluronate matrix for bone regeneration

A new type of collagen-hyaluronate (COL/HA) matrix was synthesized by cross-linking collagen fibers with modified hyaluronate polymers bearing active formyl groups. The resulting matrix is a three-dimensional scaffold consisting of interconnected pores with an average size of 40 microm and a high pore volume/surface area ratio. The covalent nature of the bond between the collagen fibers and the modified hyaluronate was demonstrated by extended elution with phosphate buffered saline and by extraction in increasing ionic gradients. The fraction of covalently bound hyaluronate in the matrix ranged from 5 to 25 w%. The total hyaluronate content of the COL/HA matrix affected both the in vitro non-enzymatic and enzymatic degradation as well as the in vivo turnover. When implanted in cranial defects in rats, the COL/HA matrix demonstrated good biocompatibility and exhibited greater osteoconductive potential than matrices composed of either cross-linked collagen or cross-linked hyaluronate alone.