Near-infrared Emission Carbon Dots Derived from Bromo-Substituted Perylene Derivatives with Simultaneously High Type I/II ROS Generation for Effective Bacterial Elimination and Tumor Ablation

Abstract

Bacterial infections and tumor tissues are characterized by complex microenvironments with uneven oxygen availability. Effective photodynamic therapy for these conditions requires photosensitizers that can perform optimally within such environments, specifically by generating both type I and II reactive oxygen species (ROS) simultaneously. Carbon dots (CDs), a type of fluorescent nanomaterial smaller than 10 nm, are commonly used to treat bacterial infections and tumors. However, their current limitations, such as short maximum absorption and emission wavelengths, significantly restrict their therapeutic efficacy in deep tissues. In response to these challenges, a new type of fluorescent carbon dots with near-infrared (NIR) absorption and emission properties is reported, featuring a maximum emission peak beyond 700 nm (NIR-I region). These CDs offer strong tissue penetration and reduced tissue absorption advantages. Additionally, bromine atom doping significantly enhances the generation of type I and II ROS through efficient photodynamic processes. In vitro studies demonstrated their high photodynamic efficacy in antibacterial and antitumor applications. Ultimately, these findings translate into significant therapeutic effectiveness for treating skin infections and tumors in vivo. This study employs bromine-doped CDs nanomaterials, which demonstrate maximum fluorescence emission in the NIR region, to achieve efficient photodynamic treatment of bacterial infections and tumor ablation in complex microenvironments.