Low temperature synthesis of chiral carbon dots for reducing H₂O₂ damage

Recently, researches focused towards the chiral nanostructures have attracted vast attention. However, the synthesis of chiral carbon dots (CDs) through one-step method is still rather scarce. Herein, a universal approach to green synthesis of chiral CDs at low temperature was proposed. In brief, L-FruCDs and D-FruCDs were obtained by only heating the fructose and chiral cysteine molecules in the sodium hydroxide aqueous solution under atmospheric pressure. Circular dichroism spectra show that these prepared CDs exhibit opposite chirality ranging from 210 to 260 nm. Specially, the prepared L-FruCDs could reduce the intracellular oxidative damage induced by hydrogen peroxide and display a superior performance than that of D-FruCDs. Mechanism studies indicate that the probably protect mechanism is ascribed to the directly consumption the intracellular ROS. And the clearance efficiency of intracellular reactive oxygen species of L-FruCDs is 3-times than that of D-FruCDs. Furthermore, this newly synthesized method is scalable by replacing fructose precursor with ascorbic acid, sucrose or lactose. In sum, our work provides a new method for the preparation of chiral CDs and achieve a great success in exploring the chiral biological effects at nanoscale.