NIR-responsive polydopamine nanosystem with on-demand release for dual antibacterial and catalytic performance

A NIR-responsive nanosystem enabled on-demand release of Ag + . • The synergistic PTT/Ag⁺ therapy enhanced antibacterial and antibiofilm performance. • The nanosystem demonstrated high catalytic performance toward organic pollutants. The bacterial resistance induced by antibiotic abuse and bacterial biofilm barriers has constituted a major challenge in the field of global public health. To address this issue, a near-infrared (NIR)-responsive polydopamine-functionalized silver nanoparticle (PDA@Ag) antibacterial system was developed to achieve dual-function antibacterial and catalytic performance. Under NIR irradiation, polydopamine exhibited excellent photothermal conversion performance, enabling direct antibacterial through a mild photothermal therapy (PTT) while simultaneously triggering the precisely controlled release of Ag⁺ via NIR-responsive, thus achieving synergistic PTT/Ag⁺ antibacterial activity. In vitro experimental results demonstrated that the system exhibited significant antibacterial efficacy against S. aureus (97.4%) and E. coli (98.6%), and effectively disrupted bacterial biofilms. Furthermore, the strong adhesion property of the polydopamine matrix effectively prevented the aggregation of Ag NPs, ensuring catalytic stability and endowing PDA@Ag with a high capability of reducing 4-nitrophenol (4-NP), with a reaction rate constant of 0.029 min⁻¹ . Given that the systemic in vivo safety requires further comprehensive evaluation, the current NIR-responsive intelligent on-demand release nanoplatform developed in this study is primarily suited for localized/superficial bacterial infection therapy. Download: Download high-res image (156KB) Download: Download full-size image