Reprogrammed Implant Surface with Enhanced Neutrophil Response for Preventing Implant-Associated Infection and Promoting Osseointegration

The onset of implant-associated infection (IAI) initiates a series of immune responses, primarily mediated by neutrophils. Bacterial aggregate formation and the presence of a hypoxic microenvironment are two major risk factors in the early stages that can impair neutrophil function and contribute to IAI and implant failure. In this study, we employed a mechanochemical approach to reprogram the implant surface using phytic acid-Zn2+ coordinated nanopillars (PA-Zn@TiNPs) and oxygen self-supporting nanoparticles. The developed PA-Zn@TiNPs combine the anti-bacterial adhesion properties of a superhydrophilic-like surface, the bactericidal effects of the nanopillars, and the chemo-biocidal effects of Zn2+ to inhibit the formation of nascent biofilms. Consequently, efficient bacteria elimination can be achieved with a minimal number of neutrophils. Additionally, the continuous oxygenation provided by the interface fuels neutrophils with reactive oxygen species, enhancing intracellular sterilization. This interface effectively prevents IAI, accelerates neutrophil turnover, and creates an immunomodulatory osteogenic microenvironment in a rat IAI model. The tailor-made reprogrammed interface significantly enhances the potential of neutrophils to prevent IAI and promote bone-implant integration.