Micro-Nanostructures of Cellulose-Collagen for Critical Sized Bone Defect Healing

Bone tissue engineering (BTE) strategies utilize biodegradable polymeric matrices alone or in combination with cells and factors to provide mechanical support to bone, while promoting cell proliferation, differentiation, and tissue ingrowth. The performance of mechanically competent, micro-nanostructured polymeric matrices, in combination with bone marrow stromal cells (BMSCs), was evaluated in a critical sized bone defect. Cellulose acetate (CA) was used to fabricate a porous micro-structured matrix. Type I collagen was then allowed to self-assemble on these micro-structures to create a natural polymer-based, micro-nanostructured matrix (CAc). Poly (lactic-co-glycolic acid) (PLGA) matrices with identical micro-structures served as controls. Significantly higher number of implanted host cells were distributed in the natural polymer based micro-nanostructures with greater bone density and more uniform cell distribution. Additionally, a two-fold increase in collagen content was observed with natural polymer based scaffolds. This study establishes the benefits of natural polymer derived micro-nanostructures in combination with donor derived BMSCs to repair and regenerate critical sized bone defects. Natural polymer based materials with mechanically competent micro-nanostructures may serve as an alternative material platform for bone regeneration.