Bimetallic metal-organic frameworks utilizing AIE for visual detection of glutathione and applications in information encryption

Glutathione (GSH) plays an important role in living organisms and is often added to food as a food additive, so it is of great importance to accurately and conveniently determine GSH in food. In this paper, a terbium and copper bimetallic metal-organic frameworks (Tbx/Cu1-x-BTC) was designed for the visualization and detection of GSH in food. Terbium ions in the Tbx/Cu1-x-BTC provide the background signal and act as an aggregation center. After reduction and aggregation-induced emission (AIE), GSH-modified copper nanoclusters (GSH-Cu NCs) enhance the red fluorescence and keep the green fluorescence unchanged. This results in a color shift of the system from green to orange. Combined with a smartphone, the RGB value of the system color was extracted to realize the visual detection of GSH. Due to the specificity of the reaction, Tbx/Cu1-x-BTC was able to specifically recognize GSH among GSH structural analogs with very good selectivity, anti-interference ability, sensitivity and accuracy. In addition, using the difference in color and excitation wavelength range between the probe and the reaction product, the probe was applied in the field of information encryption, which further expanded the application scenario of the probe. Therefore, this study provides new ideas for the detection of GSH in food and the application of fluorescence probes in the field of information encryption.