Flexible electrostatic hydrogels from marine organism for nitric oxide-enhanced photodynamic therapy against multidrug-resistant bacterial infection

The abuse of antibiotics in treating microbial infections has led to the emergence and prevalence of drug-resistant bacteria. Thus, the development of novel antibacterial materials is attracting increasing attention. Here, a series of flexible electrostatic hydrogels with excellent antibacterial ability were constructed using a mixture of nitric oxide (NO)-releasing nitrated chitosan (CSNO) and mesotetra(4-carboxyphenyl)porphine (TCPP) with salmon sperm DNA (ssDNA) solution. When cultured with gram-negative bacteria under solar simulator irradiation, TCPP-CSNOm-ssDNAn hydrogels released reactive oxygen species (ROS) and NO to produce peroxynitrite ions (ONOO−). ONOO− is efficient at killing bacteria, thereby improving the antimicrobial ability of photodynamic therapy against gram-negative bacteria. The hydrogels exhibited powerful antibacterial activity in vivo when used to treat skin infections caused by drug-resistant bacteria, making them a promising candidate for clinical applications. A string of antibacterial hydrogels that release ROS and NO synergistically can bring new possibilities for effectively killing drug-resistant bacteria and be of great value in anti-infection wound dressings and other applications.