Light-Regulated P(VDF-TrFE)/BiS Microneedle Patch with Tunable Electric Stimulation for Modulating the Healing of Burn Wound Dynamically.

As the skin wound forms, external electric stimulation (ES) is required to mimic the endogenous electric field that has been damaged, in order to mediate cellular behavior and promote tissue healing. At the same time, there are certain differences in the external electric stimulation requirements at different stages of skin wound healing. In this study, a Poly(vinylidene fluoride-co-trifluoroethylene)/Bismuth sulfide (P(VDF-TrFE)/Bi₂S₃) microneedle (MN) patch that is able to provide external ES to damaged tissue is developed. Owing to the existence of BiS, generating photoexcited electrons under near-infrared (NIR) light illumination, the electric property of the MN patch is easily adjustable to provide stage-optimized electrical stimulation. In vitro experiments show that the P(VDF-TrFE)/Bi₂S₃ microneedle patches, proving the inherent polarized bound charges of P(VDF-TrFE) and the photoexcited electrons generated by Bi₂S₃, can regulate cell behaviors associated with different stages of burn wound healing, including macrophage polarization, angiogenesis, and collagen deposition. In vivo, experiments reveal that persistent bound charges and stage-optimized photo-electrical stimulation synergistically accelerate wound healing, while the physical intervention of microneedles reduces scar tissue formation. This microneedle patch, which provides variable electrical stimulation, offers a promising strategy for enhanced burn healing.