A photoactive Dual-cationic Covalent Organic Framework Encapsulated Sodium Nitroprusside as controllable NO-releasing material for joint cation/photothermal/NO antibacterial therapy

The rational design and preparation of novel multifunctional materials harboring with combinational antibacterial activities have great demand in the fields of biomedicine. Herein, a novel antibacterial agent (DC-COF-SNP) based on a photoactive dual-cationic covalent organic framework (COF) encapsulated sodium nitroprusside (SNP) hybrid was developed. DC-COF consisted by imidazolium and viologen cation, showed a prominent broad spectrum antibacterial activity itself via damaging the negatively charged cell membrane of bacteria. Under laser irradiation, DC-COF with concurrently excellent photo-stability and high photothermal conversion efficiency (38.71%) presented an efficient photothermal antibacterial activity. Meanwhile, the electronegative SNP could be strongly absorbed in the positively charged COF, avoiding the self-decomposition of SNP. DC-COF-SNP displayed controllable NO release property under intermittent laser irradiation. As a result, a synergistic and amplified multi modalities antibacterial effect of cation, NO gas, and photothermal therapy was achieved, which could be employed as a wide spectrum antibacterial agent against both Gram-negative and Gram-positive bacteria. Therefore, this work paves an avenue for the rational preparation of promising combinational antimicrobial agents with controllable gas release capacity, thus, achieving higher therapeutic effect.