Carbon quantum dots with photo-induced enzyme activity and room-temperature phosphorescence and their application in drug analysis and anticounterfeiting

Abstract

The carbon quantum dots with enzyme-mimicking activity and phosphorescence have exhibited promising applications in biochemical detection and anticounterfeiting. Therefore, this paper reports the synthesis of carbon quantum dots (CDs@heme) with fluorescence, phosphorescence and photo-induced oxidase properties through the microwave method (5 min) using N-[3-(trimethoxysilyl) propyl] ethylenediamine, phosphoric acid, and hemoglobin as the raw materials. Also, CDs@heme were complexed with tetraethyl orthosilicate (TEOS) to prepared CDs@heme-TEOS with water-soluble phosphorescence. The best excitation and emission wavelengths for the fluorescence of the prepared CDs@heme are 370 and 446 nm, respectively, while those of the phosphorescence are 350 and 530 nm, respectively. A sensitive detection strategy for carmine has been established with detection limits of fluorescence and phosphorescence at 330 and 51 nM, respectively. Based on the inhibitory effect of tiopronin (TPN) on the photo-induced oxidase activity of CDs@heme, a colorimetric detection method for TPN has been established in the concentration range of 0.015 − 25 μM, with a detection limit of 9.8 nM, and the recovery rate for TPN enteric tablets is in the range of 99.85 % − 109.21 %. The change can be visually presented with a hydrogel as the medium. A triple information security system was developed based on the fluorescence/phosphorescence/mimic enzyme properties of CDs@heme. This research provides a new perspective and strategy for room-temperature phosphorescence and photosensitive multifunctional nanomaterials.