Sand bath assisted green synthesis of carbon dots from citrus fruit peels for free radical scavenging and cell imaging.

A sand bath assisted strategy for the synthesis of fluorescent carbon dots (CDs) using citrus fruit peels as a renewable green resource is reported in this work. The CDs were synthesized without any alkaline or acidic environment. The synthesized CDs were characterized by various spectroscopic and microscopy techniques. The CDs exhibited excellent water solubility and superior optical properties like excitation dependent emission, and multicolor fluorescence. In addition, the CDs have exhibited remarkable free radical scavenging activity (EC50: 4.7382 μg ml-1).The CDs were highly biocompatible and showed lower toxicity. The CDs when modified with folic acid have shown a significant potential as biological labels for cellular imaging at multiple excitations. Synthesis of CDs from natural fruit peels as an excellent carbon source for versatile applications has been demonstrated.