One pot green synthesis of C-dots from groundnuts and its application as Cr(VI) sensor and in vitro bioimaging agent

The emergence of fluorescent carbon dots (C-dots) has received special attention due to their distinct characteristics which are advantageous for optical sensing and bioimaging applications. Cr(VI) is considered a hazardous environmental pollutant hence requires a simple and effective method for its detection and recovery. Herein, we have synthesized both C-dots and N-doped C-dots from ground nuts employing a cost-effective and green hydrothermal method. N-C-dots exhibits a remarkably enhanced quantum yield (17.6%) as compared to undoped C-dots (7.8%). In addition,the N-C-dots showed amazing selectivity towards Cr(VI) in the metal sensing application. Cr (VI) induced quenching of fluorescence was recovered using Humic acid as well as Glutathione thus exhibiting an off-on type sensing mechanism. The limit of detection (LOD) for Cr(VI) using N-C-dots was found to be 0.1 mg/L. C-dots possess comparatively low cytotoxicity than N-C-dots at higher concentration thereby making them an efficient candidate for bioimaging of MCF-7 cells.