Effects of fibrous collagen/CDHA/hUCS biocomposites on bone tissue regeneration.

Collagen- and bioceramic-based composites have been widely used in hard tissue engineering because they are analogous to the organic/inorganic constituents of native bones. However, biocomposites based on collagen and bioceramics show low mechanical stiffness and limited osteogenic activities. To elevate the low biophysical and biological activities, we have introduced a new biocomposite structure. Herein, we propose a biocomposite mimicking not only the physical structure of the extracellular matrix (ECM) structure but also the biochemical components of native bone tissues. Several components including fibrillated collagen, calcium-deficient hydroxyapatite (CDHA) obtained from α-tricalcium phosphate hydrolysis, and human umbilical cord serum (hUCS) were used to generate a unique structure of the biocomposite. The 3D-printed composites were topographically similar to the nanofibrous ECM and exhibited a mechanically stable structure. We also evaluated the in vitro biocompatibilities of the biocomposite using human adipose stem cells and found that the collagen/hUCS/CDHA scaffold accelerated the in vitro osteogenic differentiation of human adipose-derived stem cells and in vivo osteogenesis in a mastoid obliterated rat model.