Highly reproducible SERS sensor based on self-assembled Au nanocubic monolayer film for sensitive and quantitative detection of glutathione

Abstract

The detection of glutathione (GSH) in human serum is significant for the clinical diagnosis of various diseases, such as Alzheimer's disease and cancer. A sensitive surface enhanced Raman scattering (SERS) sensor is proposed to detect low-concentration biomolecule GSH. The sensor is built based on a dense monolayer film of self-assembly Au Nano cubes. The film has an excellent enhancement effect on the probe molecule DTNB. After the GSH molecule is continuously added, the disulfide bond in DTNB breaks into TNB molecule. In a neutral or alkaline environment, TNB will be hydrolyzed into anions, and bind to the surface of the positively charged Au NCs film through electrostatic interaction, thereby enhancing the Raman spectroscopy of TNB. As a result, the proposed sensor can detect low concentrations GSH. The detection limit is 50 nM, and the relative spectral intensity of TNB characteristic peak existed good linear relationship with the concentration of GSH between 50 and 750 nM. The SERS substrate used in the sensor is easy to prepare, with high uniformity and reproducibility, the sample does not require complicated pre-processing and preparation. The SERS sensor provides a novel strategy for sensitive and quantitative detection of the trace analytes and has potential for clinical applications.