Porphyrins functionalized covalent organic frameworks for enhanced photodynamic and photothermal antibacterial

Abstract

Porphyrins, as important organic photosensitizers, have attracted widespread attention in photodynamic and photothermal therapy. However, the poor water solubility of porphyrins causes their tendency to aggregate in living organisms, resulting in unsatisfactory photodynamic and photothermal effects. In this work, we have ingeniously designed a kind of photoactive COFs-Tph by covalent coupling hydrophobic porphyrin (Tph) on the surface of porous covalent organic frameworks (COFs) with free aldehyde groups. Under 660 nm light irradiation, the proposed COFs-Tph exhibit high ¹O₂ generation ability and photothermal conversion efficiency (50.56 %) simultaneously. Importantly, the COFs-Tph display the obviously enhanced photodynamic and photothermal performance compared to Tph, which is attributed not only to the high loading capacity of COFs on Tph, but also to covalent coupling between COFs and Tph that improves the dispersibility of Tph. Because of the excellent phototherapeutic ability, the COFs-Tph are used as the antibacterial nanoreagents to kill 100 % both Gram-negative and Gram-positive bacteria in just 5 min. This work develops a powerful strategy to construct phototherapeutic nanoreagents with enhanced photodynamic and photothermal properties and achieve efficient antibacterial purposes.