PEGylated Coating Affects DBM Osteoinductivity In Vivo by Changing Inflammatory Responses

PEGylation is a widely used modification in device coating or drug delivery by combing materials with poly(ethylene glycol) (PEG). In the present study, a well-established rat ectopic bone formation model was used to elucidate how PEGylated coating affects demineralized bone matrix (DBM) osteoinductivity in vivo by changing the inflammation events at the early phase of implantation. A range of cell-matrix interactions was characterized at the cellular and functional levels, including growth factor activity and kinetics, immune cell migration and activation, and bone formation in vivo. After 28 days, DBM's bone formation potential decreased in groups with increasing PEG concentration in the gelatin carrier. The increasing PEG concentration did not affect DBM's osteoinductive growth factor release or activity. However, increasing PEG cross-linking concentration resulted in decreased DBM-related early phase inflammatory reactions, reduced neutrophil infiltration, decreased coating material degradation, lowered the total number and active mast cells, and decreased CD80+ macrophage expression. Understanding and controlling cell-material responses may improve the design and development of functional medical devices.