Self-powered biodegradable piezoelectric fibrous composites as antibacterial and wound healing dressings

Antibacterial properties are crucial for wound dressings to prevent bacterial infections that impede the healing process. However, achieving portability, permeability and biodegradability simultaneously in wound dressings is a challenging and essential task. Herein, we fabricated self -powered piezoelectric and biodegradable wound dressings with antibacterial properties using fibrous composites of poly(L-lactic acid) (PLLA), poly(ethylene glycol) (PEG) and tetragonal barium titanate (BT). During the initial treatment stage, the piezoelectricity of the composites effectively generated voltages to eliminate bacteria. As the composite degraded, the piezoelectricity dynamically and gradually diminished, resulting in relatively lower electrical signals to promote wound healing. The in -situ skin elongation of a rat in relaxed and active states was first evaluated through measuring the mechanical deformation of conductive nanofibers, illustrating that approximately 6 %-18 % strain was generated on a rat skin in daily life. Furthermore, the piezoelectric output of the fibrous composites was characterized by using a homemade dynamic stretching apparatus under the predetermined strain and frequency that mimicked the stretching deformation of the rat skin. To balance the biodegradability and antibacterial effects, PLLA composite fibers were optimized by incorporating 10 % PEG and 4 % BT, which effectively generated piezoelectric voltages from 2.2 to 4.2 V under the skin deformations from 6 % to 18 %. The fibrous composites produced reactive oxygen species to kill 99 % of bacteria in 60 min and maintained great biocompatibility even at the strain of 18 %. In vivo experiments demonstrated that the fibrous dressing led to a healing rate of 91 % on day 7 and a fully wound healing with an intact epidermis after 14 days. The study provides an innovative approach to develop self -powered piezoelectric and biodegradable fibrous composites for antibacterial wound healing applications.