Development of an injectable composite as a carrier for growth factor-enhanced periodontal regeneration

Aim: Biomaterials are often applied in periodontal therapy; however, not always well adapted for tissue regeneration. The objective of this study was to evaluate the physico-chemical properties and biocompatibility of an injectable, in situ setting composite for growth factor-enhanced periodontal regeneration. Material and Methods: The composite constitutes bioresorbable poly(lactic-co-glycolic acid) (PLGA) and additives forming in situ a matrix designed as a carrier for recombinant human growth/differentiation factor-5 (rhGDF-5). In vitro characterization included the porosity, biointeraction, biodegradation, injectability, and biological activity of released rhGDF-5. Biocompatibility was compared with granular β-tricalcium phosphate and an absorbable collagen sponge using a canine periodontal defect model. Results: The PLGA composite showed a highly porous (500-1000 μm) space-providing structure. It effectively induced coagulation exhibiting an intimate interaction with the fibrin clot. The biphasic biodegradation was complete within 4 weeks. The composite was conveniently injectable (90.4±3.6 N) for ease of use. It exhibited a sustained rhGDF-5 release over 4 weeks (40.8%) after initial burst (3.4%) detected by ALP activity. Sites receiving the composite showed limited, if any, residuals and had no appreciable negative effect on periodontal wound healing. There were no noteworthy inflammatory lesions in sites receiving the PLGA composite. Conclusion: Characteristics of the PLGA composite makes it an attractive matrix to support native wound healing and rhGDF-5-enhanced periodontal regeneration.