IADR Abstract Archives
Cu++-Free Click Hydrogel Delivery of rhBMP2 for Therapeutic Bone Regeneration
Objectives: Bone morphogenetic protein-2 (BMP-2), a potent osteoinductive agent, has been used for enhancing osseointegration of dental implants. rhBMP-2 is traditionally delivered using collagen scaffolds, but drawbacks to this method of delivery include an undesirable burst release of the therapeutic, off-target effects, and ectopic bone formation. This research examined if an injectable PEG-based Cu++-free click hydrogel that rapidly polymerizes in vivo (QuickGel) could be used for in situ delivery of rhBMP-2 to address these complications.
Methods: QuickGel+/-rhBMP-2 were incubated in media over 10 days. Activity of the released BMP-2 was tested using a human pre-osteoblast-like cell line (MG63). Cultures were incubated with conditioned media (A). In addition, a coculture experiment was performed to test release and activity of the BMP-2 in situ by placing QuickGel+/-rhBMP-2 in transwells (B). DNA was measured in cell layer lysates, and osteogenic markers (osteocalcin, osteopontin, and osteoprotegerin) were assessed in conditioned media by ELISAs (n=6). Safety testing was performed using mouse MC3T3-E1 pre-osteoblasts, human MRC-5 lung fibroblasts and MG63 cells compared to media incubated on a polyethylene disc and cytotoxic latex disc (n=6).
Results: There was a burst release of BMP-2 within 48 hours, followed by sustained release over the 10-day test period. Production of osteogenic markers per cell and decreased total DNA content were observed in both A and B assays. In vitro safety testing showed the hydrogel was non-cytotoxic across the three cell lines.
Conclusions: Results demonstrated that QuickGel is a viable, localized, non-cytotoxic delivery vehicle for rhBMP-2 with a tunable release profile for enhancing bone formation in dental and craniofacial applications. Safety testing of the hydrogel showed it had no effect on cell viability. The hydrogel is able to extend release of the therapeutic over the course of 10 days, and BMP-2 released from the gel maintains its biological activity, inducing osteoblast differentiation.
Methods: QuickGel+/-rhBMP-2 were incubated in media over 10 days. Activity of the released BMP-2 was tested using a human pre-osteoblast-like cell line (MG63). Cultures were incubated with conditioned media (A). In addition, a coculture experiment was performed to test release and activity of the BMP-2 in situ by placing QuickGel+/-rhBMP-2 in transwells (B). DNA was measured in cell layer lysates, and osteogenic markers (osteocalcin, osteopontin, and osteoprotegerin) were assessed in conditioned media by ELISAs (n=6). Safety testing was performed using mouse MC3T3-E1 pre-osteoblasts, human MRC-5 lung fibroblasts and MG63 cells compared to media incubated on a polyethylene disc and cytotoxic latex disc (n=6).
Results: There was a burst release of BMP-2 within 48 hours, followed by sustained release over the 10-day test period. Production of osteogenic markers per cell and decreased total DNA content were observed in both A and B assays. In vitro safety testing showed the hydrogel was non-cytotoxic across the three cell lines.
Conclusions: Results demonstrated that QuickGel is a viable, localized, non-cytotoxic delivery vehicle for rhBMP-2 with a tunable release profile for enhancing bone formation in dental and craniofacial applications. Safety testing of the hydrogel showed it had no effect on cell viability. The hydrogel is able to extend release of the therapeutic over the course of 10 days, and BMP-2 released from the gel maintains its biological activity, inducing osteoblast differentiation.