Confined assembly of 2D biofilms at the air-water interface for versatile surface biofunctionalization of osteogenic implants

The increasing aging population has created a huge demand for osteogenic implants. In this study, we report a biogenic, scalable, and osteogenic biofilm for in vivo osseointegration. Experimental and simulation studies showed vertical migration and horizontal juxtaposition of lactoferrin (LF) nanoaggregates at the air-water interface, forming 2D biofilms with highly controllable thickness, roughness, and adhesiveness. The inherent biocompatible, antibacterial, and osteogenic properties of LF clearly translated the biofilms into facile coatings for versatile surface biofunctionalization of various implants such as polylactic acid. Specifically, the defective tibiae in rat models receiving such implants featured a 149% increase in bone volume/tissue volume and a 57% increase in the number of bone trabeculae after an 8-week recovery, making the LF-based biofilms the best among the biomolecular osteo-regenerative coatings reported so far. This study provided a compelling example of how the inherent biofunctions of natural proteins can be combined with surface biofunctionalization towards advanced biomedical applications.