Green synthesis of carbon dots from fish scales for selective turn off–on detection of glutathione

Abstract

Carbon dots as fluorescent probes were fabricated using readily available grass carp fish scales as the carbon source via one-step synthesis based on a pyrolytic reaction. The as-prepared grass carp fish scale carbon dots (GF-CDs) exhibited good biocompatibility and excellent optical properties with a high fluorescence quantum yield of 23.8%. Glutathione (GSH) is an essential small tri-peptide molecule present in every body cell and plays a crucial role in vivo and performs a wide range of biological functions. Ag⁺ can effectively quench the fluorescence of GF-CDs because of the electron transfer between GF-CDs and Ag⁺; however, the addition of GSH can significantly increase GF-CD-Ag⁺ fluorescence. Because of their combination with Ag⁺ and GSH, GF-CDs show selective fluorescence recovery. GF-CDs can serve as fluorescent probes for GSH detection. This detection method covered a wide linear range (1.6–36.0 μg mL⁻¹) with the lowest detection limit of 0.77 μg mL⁻¹ and manifested great advantages such as a short analysis time, good stability, repeatability, and ease of operation.