Rapid on-demand in-situ gelling and dissociation of PEG bottlebrush hydrogel via light-mediated grafting-through polymerization for full-thickness skin wound repair

Developing light-triggered in situ forming dynamical hydrogels with on-demand dissolvable and antioxidation capacities to promote wound healing is highly desired yet challenging. Herein, we prepared an in situ forming bottlebrush hydrogel with on-demand dissolution capacity from two thioctic acid (TA)-functionalized poly(ethylene glycol)s (PEGs) telechelic (TA-PEGs) prepolymers via a light-mediated grafting-through polymerization strategy. In response to light irradiation, TA-PEGs could undergo rapid ring-opening polymerization to generate a highly branched bottlebrush network with dynamic disulfide bonds and simultaneously load water-soluble curcumin complexes with excellent antioxidant activity, enabling fast in situ gelation in 3 min to achieve perfect coverage of wound sites with different shapes. Furthermore, the resulting bottlebrush hydrogel dressing can achieve facile and painless removal of the dressing via rapid on-demand dissolution of the hydrogel during dressing changes. Meanwhile, thanks to its dynamical feature of the disulfide-based network, the hydrogel possesses excellent self-healing ability and shape adaptability that can maintain the interiority of the dressing during application and thus prolong its service life. In vitro evaluation demonstrates that this PEG bottlebrush hydrogel possesses favorable hemocompatibility, cytocompatibility, and antioxidant capacity. More importantly, in vivo experiments confirmed that the hydrogel promotes angiogenesis, dermal collagen synthesis, and alleviates the excessive ROS damage, thus providing more beneficial conditions to accelerate full-thickness skin wound healing.