Green Making of Calcium and Nitrogen Doped Carbon Quantum Dots for Sensing of Pb (II) ion and Anticancer Activity

Abstract

Carbon Quantum Dots (CQDs) have garnered significant attention due to their excellent optical properties, making them suitable for various applications. The present study investigates the influence of hetero atoms of Nitrogen, Oxygen, and Calcium on the structural aspects and applications of Carbon Quantum Dots especially in terms of fluorescence sensing and antioxidant properties. A facile and non-toxic microwave-assisted method was used to prepare Nitrogen-doped Carbon Quantum Dots (NCQDs) and Calcium-doped NCQDs (Ca-NCQDs) from the precursor of Crassostrea virginica seashell using urea and Citrus lemon extract as doping agents, respectively. The impact of doping on the structure-activity relationship and emission (fluorescence) properties of the prepared sample were examined by comparing their microstructure, surface morphology, and elemental composition using analytical tools. Upon evaluating the luminescence and antioxidant activities of NCQDs and Ca-NCQDs, the Calcium doped CQDs showed better intense green fluorescence and enhanced sensing activity of Pb (II) ion while, the Nitrogen-doped CQDs showed more antioxidant and anticancer potential under the given experimental conditions. The results of the study provide great scope for the fabrication of a Pb (II) sensor and anti-cancer agent.