Use of a chondroitin sulfate bioadhesive to enhance integration of bioglass particles for repairing critical-size bone defects.

Replacement of autogenous or allograft bones by artificial graft materials represents a growing area of interest in current bone repair strategies. Bioactive ceramics in particulate form, such as Bioglass (BG) 45S5, stimulate bone mineralization comparable to autologous bone grafts, but have potential issues of particle migration and inflammation. The aim of this study was to employ a chondroitin sulfate- (CS-) based bioadhesive to improve integration of the bioglass (NovaBone Putty) to prevent particle migration and promote bone regeneration. This BG-CS composite can encapsulate bone marrow (BM) to form a mechanically stable construct, BG-CS-BM. Rheological characterization confirmed the formation of CS-BM hydrogel by reacting the CS-based bioadhesive with the BM. Compared to the bioglass, the BG-CS-BM composite demonstrated a superior capacity to maintain construct integrity under both aqueous and turbulent environments in vitro. After implantation for 4 weeks in a critical-size distal femoral bone defect in a rabbit model, there was significantly greater bone growth in BG-CS-BM as compared to bioglass-only and the empty control. Unlike BG-CS-BM, BG-CS recruited BM in situ from the bone defect. BG-CS demonstrated a similar effect in bone formation but at a comparatively slower rate than BG-CS-BM over 6-weeks' implantation.