Effect of composite SiO₂@AuNPs on wound healing: in vitro and vivo studies

Recently gold nanomaterials have been widely applied in the biomedical field, but their biosafety is still controversial. We immobilized small gold nanoparticles (AuNPs) on a large silica substrate to form silica-gold core-shell materials (SiO2@AuNPs) via classical seed-mediated growth. In vitro, 500 nm-SiO2@AuNPs could promote the proliferation of mouse embryonic fibroblast cells (NIH/3T3). The results of transmission electron microscope (TEM) showed that the vast majority of particles did not enter cells and that the morphology of microtubules experienced no change as observed in the confocal microscope images. The mechanism may be that the large silica substrate kept AuNPs outside the cells and the nano-size concavo-convex gold shell facilitated to cell adhesion, resulting in the proliferation. In vivo, a cutaneous full-thickness excisional wound rat model was applied to assess the healing efficiency of 500 nm-SiO2@AuNPs. The results indicated that SiO2@AuNPs could promote wound healing, which was potentially related to the anti-inflammatory and antioxidation of AuNPs. The pathological finding showed that the healing levels of SiO2@AuNPs were significantly better than those of the control groups. Our study may provide insight into the application of silica-gold core-shell materials in the treatment of cutaneous wounds.