Dual‐Responsive Nanocomposites for Synergistic Antibacterial Therapies Facilitating Bacteria‐Infected Wound Healing

Abstract The rising dangers of bacterial infections have created an urgent need for the development of a new generation of antibacterial technologies and therapeutics. Antibacterial photodynamic therapy (PDT), considered as a noninvasive treatment with no drug resistance, has become a new promising photochemistry‐involved treatment strategy. Titanium oxide (TiO 2 ) is proved to be a very efficient PDT agent among the photosensitive materials, while the property of a large bandgap of TiO 2 makes it only be excited by ultraviolet light, which is harmful to organisms. In this work, a novel ligand‐to‐metal charge transfer (LMCT) mediated TiO 2 PDT strategy is proposed via the harmless near‐infrared light irradiation. By choosing a mussel‐inspired material, polydopamine (PDA) is involved in forming mesoporous TiO 2 @PDA nanoparticles (mTiO 2 @PDA NPs). The catechol groups of PDA can attach the TiO 2 tightly even in colloidal environments, and can also form the LMCT bridge, exciting TiO 2 to exert PDT function via 808 nm irradiation. Combining the sonodynamic therapy (SDT) of TiO 2 and the photothermal therapy properties of PDA, this simple structure mTiO 2 @PDA enables synergistic antibacterial applications with multiple functions under the dual excitation of NIR and ultrasound. This reliable all‐in‐one NPs can achieve great antibacterial effect and a rapid repair of infected wounds.