Mechanochemical Reprogramming of Implant Surfaces for Preventing Implant-Associated Infection

The initiation of implant-associated infection (IAI) elicits a series of immune responses primarily mediated by neutrophils. The formation of bacterial aggregates and the presence of a hypoxic microenvironment, which arise shortly after implantation, can be significant risk factors that compromise neutrophil function and contribute to IAI.

In this study, we utilized a mechanochemical approach to modify the implant surface with TiO2 nanopillar arrays coordinated with phytic acid-Zn2+ (PA-Zn@TiNPs) and oxygen self-supporting nanoparticles. The engineered interface of PA-Zn@TiNPs incorporated several properties that hindered the formation of early biofilms, encompassing antibacterial adhesion, mechanobactericidal effects, and chemobiocidal effects.

Simultaneously, the continuous oxygenation provided neutrophils with reactive oxygen species, enabling effective eradication of bacteria both on the implant surface and within the neutrophils. Furthermore, this surface modulation strategy expedited neutrophil apoptosis and facilitated M2 macrophage-mediated osteogenesis at the bone-implant interface in a rat model of IAI.

Targeting neutrophils for immunomodulation represents a practical and effective strategy to prevent IAI and enhance bone-implant integration following implantation.