The Three-Pronged Strategy: A Bilayer Hydrogel Treats Diabetic Chronic Wound through Microalgae Oxygen Therapy, Ag─FA NP Antibacterial, and Synergistic Scavenging of ROS

Due to hypoxia, excessive reactive oxygen species (ROS), dense bacterial biofilms, and complex inflammatory microenvironment, chronic diabetic wound healing presents a huge challenge. Currently, sustainable treatments for this multifaceted problem have not been found. Here, microalgae and silver (Ag)─fulvic acid (FA) NPs are used to develop a multinetwork hydrogel (C@Ag─KGCM) based on oxidized konjac glucomannan (OKG) for the treatment of diabetic chronic wound (DCW). The lower hydrogel carries microrobots of Chlamydomonas rheinhardtii (C. rheinhardtii) , which continuously release bio-oxygen under light irradiation to alleviate hypoxia in deep wound tissues. The upper layer carries Ag─FA NPs formed by Ag + and FA self-assembly chelation complex, which can effectively inhibit bacterial growth and remove bacterial biofilms through photothermal-therapy-based Near - Infrared (NIR) 808 nm. C. reinhardtii and Ag─FA NPs synergistically scavenge excessive ROS. Therefore, a new concept of “three-pronged strategies” that addresses multiple problems in the wound microenvironment of diabetic patients has been proposed. Histological analysis of wound tissues shows that the C@Ag─KGCM bilayer hydrogel can promote chronic diabetic wound healing and tissue regeneration, indicating promising potential for its treatment of DCW healing.