Self-oxidized Carbon Dots with Enhanced Near-infrared Absorption for Highly Effective Photothermal Therapy of Tumor

Abstract

Near-infrared (NIR) photothermal agents are crucial for tumor therapy due to their unique ability to penetrate deep into tissues, overcoming the limitations of light scattering and absorption. In this study, we established a facile synthetic approach to extend the absorption range of carbon dots (CDs) into the NIR region via a self-oxidation mechanism. Using citric acid and uric acid as precursors, we prepared three types of CDs (WCDs, WACDs, and EACDs). Their oxidized forms (ox-WCDs, ox-WACDs, and ox-EACDs) exhibited broadened NIR absorption, attributable to an increased number of C=O groups. Among these, ox-EACDs exhibited superior performance with a remarkable photothermal conversion efficiency of 75.23%. In vitro studies demonstrated over 90% tumor cell ablation under NIR irradiation, whereas in vivo tests revealed rapid tumor heating to approximately 65 °C, leading to complete tumor regression. These results indicate that ox-EACDs represent a promising photothermal agent, integrating strong NIR absorption, high efficiency, and excellent biosafety for photothermal therapy application.

Keywords

Carbon dot / Near-infrared / Photothermal therapy / Antitumor / Self-oxidation

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