Engineering Carbon Nanotube-Based Photoactive COF to Synergistically Arm a Multifunctional Antibacterial Hydrogel

Enhancing the covalent organic framework (COF)'s photocatalytic ability synergistically with gelling formulations remains an urgent challenge for extended bio-applications. Herein, COF is homogeneously coated on an oxidized carbon nanotube (OCNT) and coordinated by Fe3+ to obtain tubular nanocomplex OCNT@COF-Fe (O@CF). The results showed that the photodynamic reactive oxygen species (ROS) generation ability of O@CF is enhanced due to the wrapped OCNT and the coordinated Fe3+, which can respectively serve as intermolecular charge transfer channel and electron acceptors/substrates (O2 and H2O) adsorbent to narrow the energy band gaps, increase the light absorption, and decrease the photogenerated carrier recombination. Synergistically, O@CF exhibited pH-dependent peroxidase and catalase activities, which further enhanced ROS generation and relieved hypoxia, respectively. Meanwhile, O@CF possessed degradation of COF coatings-dependent photothermal performances. Then, O@CF is evenly incorporated into Schiff base hydrogel via the COF coating-participated covalent cross-linking, to obtain an electroconductive hydrogel OCNT@COF-Fe@Gel (O@CF@G). This O@CF@G can not only improve the mechanical properties of pure gel but also inherit the multifunction of O@CF. Consequently, it can well adhere to diabetic wounds for imbibition, drug-resistant biofilm elimination, gram-positive and negative bacteria killing, hypoxia alleviation, and intercellular electrical signal conduction, thus accelerating wound healing. A tubular nanocomplex of Fe-doped covalent organic framework (COF) coated on carbon nanotube which can synergistically modulate photo-enzyme catalytic activities for both reactive oxygen species (ROS) and O2 generations is prepared and exploited to arm a multifunctional antibacterial hydrogel. This hydrogel can accelerate infected diabetic wound healing via synergistic photothermal-combined multiple photodynamic properties, pH-dependent peroxidase and catalase activities, presented electroconductibility, and improved injectability and viscoelasticity.image