Carbon dots (CDs) have gained significant interest because of their potential in biomedical applications. Nevertheless, developing CDs with efficient photoinduced charge separation for tumor photodynamic therapy (PDT) remains a challenge. This study presents a novel class of supra-carbon-dots (supra-CDs) developed by fusing red emissive CDs with 2,3-dicyanohydroquinone (DCHQ) via post-solvothermal treatment. In supra-CDs, the core, acting as electron donors, is formed by assembled CDs with substantial sp2 domains, the fused interface originating from DCHQ with electron-withdrawing groups functions as the electron acceptor. This configuration creates the unique donor-acceptor nanostructure. Upon white light irradiation, the excited electrons from the assembled CDs were transferred to the electron-withdrawing interface, whereas the photogenerated holes were retained within the assembled CDs as radicals, leading to effective photoinduced charge separation. The separated photogenerated electrons then react with oxygen to generate superoxide radicals. Simultaneously, the photogenerated holes undergo oxidation of crucial cellular substrates. This dual action underscores the exceptional cell-killing efficacy of supra-CDs. Moreover, the increased particle sizes (~20 nm) ensure supra-CDs to exhibit a notable capacity for tumor accumulation via the improved permeability and retention effect, thereby achieving satisfactory anti-tumor PDT efficacy in a mouse subcutaneous tumor model.

中文翻译：

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具有长寿命光生自由基的供体-受体型超碳点促进肿瘤光动力治疗


碳点（CD）因其在生物医学应用中的潜力而引起了人们的极大兴趣。然而，开发具有有效光致电荷分离功能的 CD 用于肿瘤光动力治疗 (PDT) 仍然是一个挑战。本研究提出了一类新型超碳点（supra-CD），其通过后溶剂热处理将红色发射 CD 与 2,3-二氰基氢醌 (DCHQ) 融合而开发。在supra-CD中，充当电子供体的核心由具有大量sp2结构域的CD组装而成，源自DCHQ的融合界面与吸电子基团充当电子受体。这种配置创造了独特的供体-受体纳米结构。在白光照射下，来自组装的碳点的激发电子转移到吸电子界面，而光生空穴作为自由基保留在组装的碳点内，从而实现有效的光致电荷分离。分离的光生电子然后与氧反应生成超氧自由基。同时，光生空穴经历关键细胞底物的氧化。这种双重作用凸显了超 CD 的卓越细胞杀伤功效。此外，增加的粒径（~20 nm）确保supra-CD通过改善的渗透性和保留效应表现出显着的肿瘤积累能力，从而在小鼠皮下肿瘤模型中获得令人满意的抗肿瘤PDT疗效。