The presence of excessive ROS can cause much harm to the human body and can even cause diseases. Therefore, it is important to detect and remove ROS, but there is no ideal method available for this at present. In this research, using procyanidins, a type of plant extract with strong reducibility, as raw materials, fluorescent carbon dots (CDs) were prepared by a hydrothermal method. The proanthocyanidin-based carbon dots (PCDs) emit a light-green colored light under UV irradiation. The PCDs retain the strong reducibility of procyanidins and are highly water-soluble compared with procyanidins. The PCDs, in addition to having good biocompatibility, also have the superior properties of radical scavenging activity and cell imaging. In in vitro experiments, 1,1-diphenyl-2-picrylhydrazyl (DPPH; 100 μM) was reduced by 30% when PCDs were added up to a concentration of 87.5 μg mL⁻¹. At the same time, the fluorescence quenching correlates with the concentration of hypochlorite and hydrogen peroxide and has a good linearity in the range of 250–2250 nM and 60–180 μM with a detection limit of 3.676 nM and 0.602 μM, respectively. Based on the previously described advantages, PCDs have potential as a biomedicine.

中文翻译：

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来自原花青素的高级还原碳点可用于自由基清除和细胞成像

过量的ROS的存在会对人体造成很大伤害，甚至可能导致疾病。因此，检测和去除ROS很重要，但是目前尚无理想的方法。在这项研究中，使用原花青素（一种还原性强的植物提取物）作为原料，通过水热法制备了荧光碳点（CD）。原花青素基碳点（PCD）在紫外线照射下发出浅绿色的光。PCD保留了原花青素的强还原性，并且与原花青素相比具有很高的水溶性。PCD除了具有良好的生物相容性外，还具有自由基清除活性和细胞成像的优越性能。在体外实验中，当添加PCD浓度达到87.5μgmL ^-1时，1,1-二苯基-2-吡啶并肼基（DPPH; 100μM）降低了30％。同时，荧光猝灭与次氯酸盐和过氧化氢的浓度相关，并且在250–2250 nM和60–180μM的范围内具有良好的线性，检出限分别为3.676 nM和0.602μM。基于先前描述的优点，PCD具有作为生物医学的潜力。