Biodegradable piezoelectric skin-wound scaffold

Electrical stimulation (ES) induces wound healing and skin regeneration. Combining ES with the tissue engineering approach, which relies on biomaterials to construct a replacement tissue graft, could offer a self stimulated scaffold to heal skin-wounds without using potentially toxic growth factors and exogenous cells. Unfortunately, current ES technologies are either ineffective (external stimulations) or unsafe (implanted electrical devices using toxic batteries). Hence, we propose a novel wound-healing strategy that integrates ES with tissue engineering techniques by utilizing a biodegradable self-charged piezoelectric PLLA (Poly (L-lactic acid)) nanofiber matrix. This unique, safe, and stable piezoelectric scaffold can be activated by an external ultrasound (US) to produce well-controlled surface-charges with different polarities, thus serving multiple functions to suppress bacterial growth (negative surface charge) and promote skin regeneration (positive surface charge) at the same time. We demonstrate that the scaffold activated by low intensity/low frequency US can facilitate the proliferation of fibroblast/epithelial cells, enhance expression of genes (collagen I, III, and fibronectin) typical for the wound healing process, and suppress the growth of S. aureus and P. aeruginosa bacteria in vitro simultaneously. This approach induces rapid skin regeneration in a critical-sized skin wound mouse model in vivo. The piezoelectric PLLA skin scaffold thus assumes the role of a multi-tasking, biodegradable, battery-free electrical stimulator which is important for skin-wound healing and bacterial infection prevention simultaneuosly.

Automated summary

Electrical stimulation combined with tissue engineering techniques using a biodegradable self-charged piezoelectric PLLA nanofiber matrix can effectively promote wound healing and prevent bacterial growth. This novel approach utilizes an external ultrasound to activate the piezoelectric scaffold, generating controlled surface charges with different polarities that suppress bacterial growth and promote skin regeneration simultaneously. In vitro and in vivo experiments demonstrate the efficacy of this multi-tasking, battery-free electrical stimulator in facilitating cell proliferation, gene expression related to wound healing, and bacterial infection prevention.