“Bacterial Suicide”: An Aminal-Linked Covalent Organic Polymer with Infection-Microenvironment-Enhanced Synergistic Photothermal and Enzymatic Activities for Wound Therapy

Abstract

The infected microenvironment provides fertile ground for bacterial growth and the progression of inflammation, making it challenging to cure related diseases. Here, a covalent organic polymer (COP)-based antibacterial agent, denoted as PF-COP, was developed. PF-COP has intrinsic photothermal capacity, which allows it to take advantage of the infected microenvironment for enhanced synergistic wound infection therapy. PF-COP was prepared via the copolymerization of piperazine with ferrocene diformaldehyde using catalyst-free aminal chemistry, in which the piperazine units could easily bind with acid to generate the cationic skeleton, while the ferrocene components could convert the endogenous H₂O₂ into a toxic hydroxyl radical. This effectively regulates the infection of the microenvironment. The acidified positively charged structures could enhance material adhesion with bacterial cell membranes and improve photothermal responsiveness, significantly improving the therapeutic effect. As a result, PF-COP amalgamating photothermal and enzyme catalytic capacities could serve as an infection microenvironment-enhanced therapeutic agent. It could disrupt the balance of the infection microenvironment, destroying the optimal growth environment for bacteria and inducing “bacterial suicide”, and regulate the microenvironment to promote the growth of normal cells, thus accelerating the wound healing. Therefore, this work presents a promising construction strategy for the precise development of COP-based therapeutics facilitating wound healing through direct infectious microenvironment utilization and regulation.