Development of a hydroxyapatite-poly(d,l-lactide-co-glycolide) infiltrated carbon foam for orthopedic applications

Reticulated vitreous carbon (RVC) foams are of interest in orthopedic applications due to their porous, honeycomb-like structure, biocompatibility, and bio-inert nature. Despite these desirable properties, RVC foams lack the strength necessary for orthopedic applications. Specifically, orthopedic biomaterials, whether bone scaffolds, plates or screws, must be able to withstand normal bone tissue loading at the time of implantation. This manuscript focuses on developing a composite RVC foam infiltrated with a hydroxyapatite (HA)-reinforced poly(d,l-lactide-co-glycolide) (PLGA) polymer. The HA/PLGA filler is envisioned to increase initial RVC foam mechanical stability while enabling osteoblasts to invade and deposit new tissue within the foam as the filler resorbs, providing long-term strength and osseointegration. Herein, a facile processing technique is developed which results in HA/PLGA-infused RVC foams with good internal interfacial bonding and increased modulus and strength relative to pure RVC foams. As anticipated, in vitro hydrolytic degradation studies indicate that the porous network of the RVC foam becomes progressively more accessible as the PLGA filler degrades and that the RVC foam may support improved structural integrity of the resorbing filler. Initial cell studies also demonstrate that this material system allows for robust osteoblast adhesion. These results indicate the proposed composites warrant further investigation for orthopedic applications.