Pd Icosahedral Nanoparticles Promote Skin Wound Healing by Enhancing SP1-HBEGF Axis-Mediated Keratinocytes Proliferation.

Introduction: Impaired wound healing leads to compromised cutaneous barrier and dysfunction, which still remains a challenging problem. However, safe and efficient materials and treatments for promoting wound healing are still lacking. Metal nanoparticles especially palladium nanoparticles (Pd NPs) have attracted tremendous interests in medical application in recent years, due to its unique physicochemical properties and biological inertness. Thereinto, Pd icosahedra nanoparticles (Pd Icos NPs) and Pd octahedra nanoparticles (Pd Oct NPs) have superior catalytic activity compared to other shapes but the application in skin wound healing have not been studied and reported.

Methods: Pd Oct NPs and Pd Icos NPs were synthesized by seed-mediated growth method and one-step synthesis method and characterized by series physical chemical assays. The acute full-thickness skin excision wound mouse model was used to access the wound healing potential and screen out the effective materials-Pd Icos NPs. Next evaluate the biotoxicity and safety of Pd Icos NPs and both in HaCaT cells and in vivo. Further examine related molecules expression by RT-qPCR and WB in HaCaT cells and wound tissues with Pd Icos treatment. Then knockout the related molecules both in HaCaT cells and in vivo to validate the molecular mechanism of these molecules in the phenotype of wound healing promoted by Pd Icos NPs.

Results: Pd Icos NPs with surface and tensile strain rather than Pd Oct NPs can promote skin wound healing. Pd Icos NPs upregulates the expression of HBEGF by promoting the production of transcription factor SP1, and contributes to keratinocytes proliferation and accelerating acute full-thickness skin wound healing.

Discussion: Pd Icos NPs represent an effective and safe material for skin wound healing, suggesting a potential novel therapeutic strategy.