A Multifunction Hydrogel-Coating Engineered Implant for Rescuing Biofilm Infection and Boosting Osseointegration by Macrophage-Related Immunomodulation

Innovative methodologies combined with scavenging reactive oxygen species (ROS), alleviating oxidative stress damage and promoting 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 with photothermal profile into the hydrogel coating composed of konjac gum and gelatin on the surface of titanium (Ti) substrate is accurately constructed. The prepared hydrogel coating exhibits excellent properties of eliminating biofilm and killing planktonic bacteria, which is based on increasing susceptibility to bacteria by the photothermal effect, biofilm-dissipation effect of D-tyrosine, as well as the bactericidal effect of tannic acid. In addition, the modified Ti substrate has effectively alleviated proinflammatory responses by scavenging intracellular excessive ROS and guiding macrophages polarization toward M2. More interesting, conditioned medium from macrophage indicates that paracrine is conducive to osteogenic proliferation and differentiation of mesenchymal stem cells. Results from rat model of femur infection in vivo demonstrate that the modified Ti implant significantly eliminates the residual bacteria, relieves inflammation, mediates macrophage polarization, and accelerates osseointegration. Altogether, this study exhibits a new perspective for the development of advanced functional implant with great application potential in bone tissue regeneration and repair.