Poly(γ-glutamic acid)-based electrospun nanofibrous mats with photodynamic therapy for effectively combating wound infection

Pathogenic bacterial infections associated with wound healing progress usually result in serious complications. Herein, biocompatible and antimicrobial electrospun nanofibrous mats with photodynamic therapy (PDT) effect were fabricated to accelerate the infected wound healing. The nanofibrous mats were fabricated by co-electrospining of polyanionic poly(gamma-glutamic acid) (gamma-PGA) and cationic photosensitizer 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin tetra (p-toluenesulfonate) (TMPyP) in aqueous solution and stabilized by the chemical crosslinking. The as-prepared nanofibrous mats can not only confer the moist microenvironment to the wound bed, but also provide potent bactericidal activity upon visible light irradiation by releasing the cytotoxic reactive oxygen species (ROS). The antibacterial assay in vitro showed that they can effectively eradicate the board-spectrum bacteria at a relatively low loading dose of TMPyP (e.g., 0.1 wt%). Meanwhile, those nanofibrous mats showed good biocompatibility with no obvious adverse effects on mammalian cells and red blood cells (RBCs). The animal test in vivo suggested that the restrained inflammatory reaction and better wound healing could be achieved upon timely and effective antibacterial treatment with negligible local toxicities. This biocompatible and antibacterial gamma-PGA-TMPyP nanofibrous mat may show great potential in practical infection-resistant applications, particularly for wound dressing applications.