A multi-function hydrogel-coating engineered implant for rescuing biofilm infection and boosting osseointegration by macrophage-related immunomodulation.

Abstract

Incurable bacterial infections, impenetrable microbial biofilm and dysregulated immune microenvironments are among the most intractable threats for the treatment of implant-associated infections (IAIs). Innovative methodologies combined with reactive oxygen species (ROS) scavenging suppress the oxidative stress damage and promote macrophage polarization to M2 phenotype may be ideal for remodeling implant-infected bone tissue. Herein, a functionalization strategy for doping Tannic acid-D-Tyrosine nanoparticles (TA-D-Tyr NPs) with photothermal profile into the hydrogel coating composed of konjac gum and gelatin on the titanium (Ti) surface w as accurately constructed, named as Ti-G-TA-D-Tyr sample. The prepared hydrogel coating exhibited excellent properties of eliminating biofilm and killing planktonic bacteria, which w as based on increasing susceptibility to bacteria by the photothermal transduction effect of TA-D-Tyr NPs, biofilm-dissipation effect of D-Tyr, as well as the bactericidal effect of TA. In addition, Ti-G-TA-Tyr sample h ad effectively alleviated proinflammatory responses by scavenging intracellular excessive ROS and guiding macrophages polarization towards M2. More interesting, conditioned medium from macrophage indicated that paracrine w as conducive to osteogenic proliferation and differentiation of mesenchymal stem cells. Results from Rat model of femur infection in vivo demonstrated that the modified Ti implant significantly eliminated the residual bacteria, relieved inflammation, mediated macrophage polarization, and accelerated osseointegration. Altogether, this study exhibited a new perspective for the development of advanced functional implant with great application potential in bone tissue regeneration and repair. This article is protected by copyright. All rights reserved.