Bioinspired by both mussel foot protein and bone sialoprotein: universal adhesive coatings for the promotion of mineralization and osteogenic differentiation
Generally, the poor osteointegration between bone implant materials and the host tissue is apt to causing the severe implant failure, accompanying with a series of postoperative complications. One of realiable and valid solution to eliminate these concerns is to improve the biointerface performance of implants via various modification methods. Although some progresses have been achieved in recent decades, it still remains great challenges and requirements to develop a facile and universial methods for implant modifcation of various materials. In this work, bioinspired by the physiological functions in osteanagenesis of bone sialoprotein (glutamic acid-rich proteins), a series of bi-functional polymers were elaborately designed and synthesized through the reversible addition-fragmentation chain transfer (RAFT) polymerization of methacryloylamido glutamic acid (MGlu) and dopamine methacrylamide (DMA). Due to the abundant catechol pendants of polymer chains, these functional polymers are able to form the stable coatings on the surface of various substrates just via an environmental-friendly and mild spin-coating process. Furthermore, the results of mineralization experiment in vitro clearly indicated that these functional polymeric coatings on titanium plates have the capability of effectively promoting the minerals deposition. Particularly, polymeric coatings composed of nearly equal monomer composition (1.0/1.2) could induce the formation of calcium phosphate (CaP) with a Ca/P ratio of 1.7/1, which is close to the ratio of calcium to phosphorus in natural hydroxyapatite. Moreover, all the polymeric coatings were prone to facilitating the adhesion, speading, proliferation and osteogenic differentiation of MC3T3-E1 cells.This promotion effects were directly affected by the composition of polymer chains, especially the contens of glutamic units.