Biomineral interface with superior cell adhesive and antibacterial properties based on enzyme-triggered digestion of saliva acquired pellicle-inspired polypeptide coatings

With the long-term clinical study of implantation materials, the problem of bioinertness on the implant surface emerged. The bioinert implant surface can cause inflammation, fibrosis, coagulation, and infections, and even threaten the life of patients. Herein, we designed and synthesized a saliva-acquired pellicle (SAP)-inspired multifunctional polypeptide DDDEEKRWRWRWGPLGVRGD (SAP-MP196-G-1) by orderly assembling the hydroxyapatite (HA)-adsorbing motif DDDEEK, antibacterial motif RWRWRW, bacterial enzyme-responding motif GPLGV, and cell adhesion motif RGD. The bioinspired polypeptide can self-assemble into nanoparticles and tightly adsorb onto the biomineral, such as the HA surface. The newly formed bio-interface exhibited two-fold higher adhesion and proliferation of MG63 cells and five-fold higher antibacterial properties against Staphylococcus aureus (S. aureus) compared to bare HA group. An in vivo study indicated that the bio-interface can promote implant wound healing and decrease infection of S. aureus on HA-coated implants. This study proposes a strategy to design a cell-adhesive and antibacterial-biomineral interface based on a dynamic enzyme-digestion reaction to effectively inhibit the side effects of implantation surface presence.