In Vitro Cellular Responses to Scaffolds Containing Two Microencapulated Growth Factors

Growth factors play an important role in the complex cascade of tissue events in periodontal regeneration, although optimal methods of delivery remain to be identified. We hypothesize that multiple delivery of growth factors, particularly via a microparticle-containing scaffold, will enhance cellular events leading to periodontal regeneration. In this study, cellular responses of periodontal ligament fibroblasts (PDLFs) in scaffolds containing microparticles (MPs) loaded with either bone morphogenetic protein (BMP)-2, insulin-like growth factor (IGF)-1, or a mixture of both MPs were evaluated, and the dual-MP-containing scaffold exhibited the release of different proteins in a sustained and independent fashion. When PDLF-seeded scaffolds were cultured in a flow perfusion bioreactor, cell metabolism and proliferation of PDLFs were significantly increased within 3 days in all IGF-1-containing scaffolds compared with those in groups lacking IGF-1 and particulate delivery enhanced these effects between 3 and 7 days. The dual-MP-containing group showed the most positive results. Both the BMP-2-in-MP and IGF-1-in-MP groups showed greater effects of alkaline phosphatase activity, more osteocalcin and osteopontin production, and more calcium deposition compared with matched GF-adsorbed groups. All osteoblastic markers were at their highest in the dual-MP-containing group at all detected time points. The combined results suggest that our dual-MP-containing scaffold can be used as a cell vehicle to positively affect cell behavior, thus exhibiting the potential to be a candidate scaffold for future periodontal tissue engineering.