The development of wound dressings with combined antibacterial activities and pro-healing functions has always been an intractable medical task for treating bacterial wound infection. Herein, a novel injectable hybrid hydrogel dressing is developed, which is doped with nitric oxide (NO) donor (N,N'-di-sec-butyl-N,N'-dinitroso-1,4-phenylenediamine, BNN6) loaded two-dimensional polydopamine nanosheets (PDA NS). The hydrogel matrix is in situ formed through dynamic Schiff base crosslinking between hydrazide-modified 𝜸-polyglutamic acid (𝜸-PGA-ADH) and aldehyde-terminated Pluronic F127 (F127-CHO). Under 808 nm irradiation, the embedded PDA NS exhibits outstanding photothermal transform properties (56.1%) and on-demand NO release. The combination of photothermal and NO gas therapy with a synergistic antibacterial effect works on both Escherichia coli and Staphylococcus aureus in vitro. Furthermore, a full-thickness skin defect model also demonstrates that the hybrid hydrogel shows outstanding antibacterial properties and effectively accelerates the wound healing process. Overall, this study provides a facile and promising method for the fabrication of PDA NS based multifunctional hydrogel dressing for the application of infectious skin wound healing.

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The use of reactive oxygen species (ROS) generators based on singleatom catalysts (SACs) has been an emerging strategy for mediating tumor therapy, however, the current systems suffer from low mass transport efficiency. Here, a novel strategy of morphology fragmentation is developed to fabricate flower-like SAC nanozymes with greatly improved 3D accessibility of active sites. Specifically, the coordinationally polymerized zeolite imidazole framework acts as a polyphenol oxidase-like enzyme to catalyze the in situ polymerization of polydopamine (PDA) which leads to blockage of micropores and crosslinking of the morphologydeteriorated ZIF nanosheets. The protective carbonization by PDA results in SAC nanozymes (C-NFs) with plenty of reopened micropores and defect mesopores (≈4 nm) in the nanopetals, large interpetal pore space (≈39 nm), high surface area (388 m 2 g −1 ), as well as an ultrahigh loading metal atoms (27.3 wt%). Subsequently, a superior peroxidases-like activity (36.6-fold increment in the turnover frequency) facilitates significantly strengthened ROS generation and damage of biomolecules. Moreover, the employment of apoferritin modification/loading leads to particle dispersion in solution and concomitant drug loading. The following cancer cell re-sensitization is proven to be advantageous for boosting ROS-facilitated treatment of drug-resistant tumors, opening up new avenues for ROS therapy.

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