Enriched graphitic N dopants of carbon dots as F cores mediate photothermal conversion in the NIR-II window with high efficiency. (June 2020)

• Record Type: Journal Article
• Authors: Geng, Bijiang; Shen, Wenwen; Fang, Fuling; Qin, Hua; Li, Ping; Wang, Xulong; Li, Xiaokai; Pan, Dengyu; Shen, Longxiang
• Is Part Of: Carbon. Volume 162(2020)
• Page Start: 220
• Page End: 233
• Publication Date: 2020-06
• Subjects: Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2020.02.053
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: We have developed the rapid synthesis of NIR–II–responsive carbon dots (NIR–II–CDs) under microwave irradiation conditions. A close correlation between the photothermal effects and graphitic N doping level is well established by two observed effects: 1) absorbance at 808 and 1064 nm was consistently proportional to the graphitic N content; 2) the photothermal conversion efficiency remarkably increased with the graphitic N content. We further revealed a distinct photothermal conversion mechanism in the NIR–II–CDs, where doped graphitic N sites as paramagnetic F centers can mediate the highly efficient NIR absorption and photothermal conversion. Importantly, readily derived NIR–II–CDs with a graphitic N doping level as high as 4.30 at.% showed ultrahigh photothermal conversion efficiency of 81.3% in the NIR-II window. Using NIR–II–CDs or their hybrid liposomal formula as single PTT or imaging-guided PCT agents, complete tumor ablation without recurrence was realized under the 1064-nm laser irradiation at low laser power densities even in the presence of the breast tissue with a thickness larger than 10 mm. Our results suggest that the photothermal properties of biocompatible CDs can be regulated in the extended NIR regions by doping a high concentration of graphitic N defects as color centers for tumor treatment with minimized side effects. Graphical abstract: Image 1