NIR-Responsive Carbon Dots Functionalized with AS1411 Aptamer: A Dual-Mode Approach to Enhanced Photothermal and Photodynamic Therapy.

Recent advancements in light-based treatments, including photodynamic therapy (PDT) and photothermal therapy (PTT), present promising alternatives to conventional cancer treatments. Moreover, combination therapy employing multiple therapeutic approaches has become a cornerstone of modern oncology, aiming to enhance treatment efficacy and overcome resistance mechanisms. This study presents an approach to enhance the effectiveness of PDT and PTT in cancer treatment by synthesizing carbon dots from the organic dye IR-820 and citric acid. The IR820-based carbon dots (IRCDs) were synthesized through a one-step hydrothermal process, inheriting the near-infrared fluorescence properties of IR-820. To facilitate targeted delivery to cancer cells, AS1411 aptamers were conjugated to the surface of IRCDs via EDC/NHS chemistry, forming IRCDs@AS1411. This transformation of IR-820 into carbon dots not only preserved its NIR fluorescence and therapeutic functionalities but also significantly enhanced the chemical stability, photostability, and resistance to photobleaching of the resulting nanomaterials. Notably, IRCDs@AS1411 exhibited a photothermal conversion efficiency approximately 35% higher than that of free IR-820. In vitro experiments demonstrated that IRCDs@AS1411 served as effective agents for bioimaging, PDT, and PTT, overcoming the limitations of traditional organic dyes and efficiently eradicating tumor cells under 808 nm laser irradiation. These findings suggest that IRCDs@AS1411 hold significant promise for advanced cancer therapy and provide a versatile platform for developing other functional nanomaterials.