Alternative Copper-Based Single-Atom Nanozyme with Superior Multienzyme Activities and NIR-II Responsiveness to Fight against Deep Tissue Infections

: Bai Jiaxiang, Feng Yonghai, Li Wenming, Cheng Zerui, Rosenholm Jessica M, Yang Huilin, Pan Guoqing, Zhang Hongbo, Geng Dechun

Publisher: American Association for the Advancement of Science

: 2023

: Research

: Research (Washington, D.C.)

: 0031

: 6

: 2639-5274

DOI: https://doi.org/10.34133/research.0031

: https://spj.science.org/doi/10.34133/research.0031

: https://research.utu.fi/converis/portal/detail/Publication/179519542

Nanozymes are considered to represent a new era of antibacterial agents, while their antibacterial efficiency is limited by the increasing tissue depth of infection. To address this issue, here, we report a copper and silk fibroin (Cu-SF) complex strategy to synthesize alternative copper single-atom nanozymes (SAzymes) with atomically dispersed copper sites anchored on ultrathin 2D porous N-doped carbon nanosheets (CuN _x -CNS) and tunable N coordination numbers in the CuN _x sites (x = 2 or 4). The CuN _x -CNS SAzymes inherently possess triple peroxidase (POD)-, catalase (CAT)-, and oxidase (OXD)-like activities, facilitating the conversion of H₂O₂ and O₂ into reactive oxygen species (ROS) through parallel POD- and OXD-like or cascaded CAT- and OXD-like reactions. Compared to CuN₂-CNS, tailoring the N coordination number from 2 to 4 endows the SAzyme (CuN₄-CNS) with higher multienzyme activities due to its superior electron structure and lower energy barrier. Meanwhile, CuN _x -CNS display strong absorption in the second near-infrared (NIR-II) biowindow with deeper tissue penetration, offering NIR-II-responsive enhanced ROS generation and photothermal treatment in deep tissues. The in vitro and in vivo results demonstrate that the optimal CuN₄-CNS can effectively inhibit multidrug-resistant bacteria and eliminate stubborn biofilms, thus exhibiting high therapeutic efficacy in both superficial skin wound and deep implant-related biofilm infections.

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