Synthesis of bio-templated clickable quantum dots and a dual-emitting organic/inorganic complex for ratiometric fluorescence visual assay of blood glucose

Abstract

With the prevalence of diabetes, rapid and simple blood glucose monitoring has become more and more important. Here, we report the synthesis of bio-templated N₃–CdZnTeS quantum dots (QDs), which are great fluorescent biological labels and were used for the fabrication of dual-emissive dye@protein–QD conjugates via copper-free click chemistry, such as the 5(6)-carboxyfluorescein@glucose oxidase-quantum dot (FAM@GOx–QDs) complex. When adding glucose, the red fluorescence of the CdZnTeS QDs sharply decreased, while the green fluorescence of FAM was invariable. A good linear relationship ranging from 0.3 to 30 μM was obtained for glucose detection, with the limit of detection as low as 0.035 μM. Notably, the DNA-bridging FAM@GOx–QDs complex exhibited enhanced enzyme activity and stability, and was applied for the differentiation of diabetic and healthy people by the naked eye.