Photoelectron-Triggered Immunomodulation: Spray-Modified Titanium Implants Promote Macrophage M2 Polarization and Osseointegration

coating with Au nanoparticles as nanocomposites, which exhibited photoelectric properties on SLA Ti under NIR irradiation. Biological evaluations indicated that NIR-activated photoelectronic signals effectively triggered M2 macrophage polarization in RAW 264.7 cells, which in turn facilitated osteogenic differentiation of MC3T3-E1 preosteoblastic cells in coculture systems. In vivo studies using a mouse femoral implant model showed significantly improved osseointegration with Au@RE/SLA Ti compared to conventional SLA Ti surfaces, accompanied by increased M2 macrophage infiltration and accelerated bone formation. This work thus integrates surface engineering using ultrasonic spray with photoelectronic immunomodulation, providing a foundation for dynamic regulation of the bone-implant interface.