Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, China.
School of Life Sciences, Beijing University of Chinese Medicine, Beijing 100029, China.
ACS Appl Mater Interfaces. 2021 Feb 3;13(4):5877-5886. doi: 10.1021/acsami.0c21949. Epub 2021 Jan 22.
Chiral carbon dots (CDs) integrated the advantages of achiral CDs and the unique chiral property, which expand the prospect of the biological applications of CDs. However, the structure control and the origin of chirality for chiral CDs remain unclear. Herein, chiral CDs were obtained by thermal polymerization of chiral amino acids and citric acid, and their handedness of chirality could be controlled by adjusting the reaction temperature, which leads to different kinds of surface modifications. With aliphatic amino acids as a chiral source, all of the CDs that reacted at different temperatures (90-200 °C) have the same handedness of the chiral source. But with aromatic amino acids as a chiral source, CDs with maintained or inversed handedness compared with the chiral source could be obtained by adjusting the reaction temperature. Below a temperature of 120 °C, the chiral source was modified with CDs by esterification and transferred the handedness of chirality; at high temperatures (above 150 °C), which mainly connected by amidation accompanying with the formation of rigid structure generated by the π conjugation between the aromatic nucleus of chiral source and the carbon core of CDs, caused the inversing of the chiral signal. Further, we investigated the chiral effects of CDs on the glucose oxidase activity for a highly sensitive electrochemical biosensor.
手性碳点（CDs）集成了非手性 CDs 的优势和独特的手性性质，扩展了 CDs 在生物应用中的前景。然而，手性 CDs 的结构控制和手性起源仍然不清楚。本文通过手性氨基酸和柠檬酸的热聚合得到了手性 CDs，通过调节反应温度可以控制其手性的 handedness，从而导致不同种类的表面修饰。以脂肪族氨基酸为手性源，在不同温度（90-200°C）下反应得到的所有 CDs 都具有相同的手性源的 handedness。但是，以芳香族氨基酸为手性源时，可以通过调节反应温度得到与手性源保持一致或相反 handedness 的 CDs。在 120°C 以下，手性源通过酯化与 CDs 结合，传递手性的 handedness；在高温（150°C 以上）下，主要通过酰胺化伴随着由手性源的芳核与 CDs 的碳核之间的π共轭形成的刚性结构的形成而连接，导致手性信号的反转。进一步，我们研究了 CDs 对手性葡萄糖氧化酶活性的影响，用于构建高灵敏度的电化学生物传感器。
