Ag+ ions-mediated fluorescence “off-on” sensing platform for the detection of glutathione based on CuS quantum dots

The development of analytical methods capable of simultaneously detecting multiple components in biological samples holds significant potential for advancing disease diagnosis. However, constructing optical platforms for continuous detection remains challenging due to limitations such as insufficient selectivity, specificity, response speed, and sensitivity. Herein, we developed a facile and efficient microwave-assisted method to rapidly synthesize CuS quantum dots (QDs) and constructed a fluorescence-based sensing platform for detecting Ag + and glutathione (GSH). The fluorescence emission of CuS QDs at 500 nm was selectively quenched upon interaction with Ag + , exhibiting a linear correlation with Ag + concentrations ranging from 0.3 to 300 μM. Notably, the quenched fluorescence could be restored by introducing GSH, accompanied by a slight redshift in the emission wavelength. This Ag + -mediated “off-on” fluorescence sensing mechanism significantly enhanced the sensitivity for GSH detection. This platform demonstrated high selectivity towards both Ag + and GSH, enabling their quantitative determination in complex matrices, including tap water, human serum, and cell lysate. This work not only presents a novel synthetic approach for CuS QDs but also achieves successive detection of Ag + and GSH without requiring complex probe modifications or the integration of multiple nanomaterials, representing a simplified yet highly effective design compared to more intricate systems. The proposed platform serves as a versatile measurement tool applicable across various fields, from environmental contaminant monitoring to the detection of key biological thiols, demonstrating a generalizable strategy for diverse analytical scenarios in both environmental and clinical contexts.