Piezoelectric and bactericidal effects of GaSe-loaded poly-L-lactic acid fibrous dressings under ultrasound stimulation for improved MRSA-infected wound healing.

The treatment of wound infections caused by bacterial invasion poses a clinical challenge due to the absence of effective therapeutic strategies. To tackle this issue, a composite ultrasound-responsive piezoelectric fibrous membrane is engineered for managing infected wounds. The membrane is composed of a Poly-L-lactic acid (PLLA) matrix embedded with gallium selenide-doped nanoparticles (GaSe NPs) to achieve synergistic therapeutic effects. In the initial phase, ultrasound activation triggers piezoelectric polarization of the PLLA component, generating reactive oxygen species (ROS) that affect the oxidative-antioxidative balance of bacteria. Subsequently, the GaSe NPs component gradually releases therapeutic ions, exerting an antibacterial effect and establishing an anti-inflammatory microenvironment that promotes macrophage polarization towards the M2 phenotype. In a murine model of full-thickness infected wounds, the membrane speeds up healing by 1.42-fold within the first five days compared to controls, showing improved angiogenesis, collagen deposition, and immune system coordination. RNA sequencing reveals timed regulation of inflammatory pathways (TNF), aligning macrophage phenotypes with different healing stages. The integration of piezoelectric-driven physical sterilization and bioactive ion-mediated biological regulation represents a novel dual-mode therapeutic approach, demonstrating significant potential for accelerating healing in infected chronic wounds.