MnO coated Au nanoparticles advance SERS detection of cellular glutathione.

Glutathione, referred to as GSH, abnormal physiologic level of GSH is an indication to some neurodegenerative diseases and cancers. A measurement of cellular GSH calls for rapid, sensitive, and selective methods. In this work, we rationally design and prepare Au@MnO core-shell composite nanoparticles combining with tetramethylbenzidine (TMB) molecules to determine intracellular GSH by Surface enhanced Raman scattering (SERS) technique. MnO plays multifunctional roles in the method, including the participation in catalyzing TMB to molecules form dimer charge-transfer complex (CTC) which own a great SERS signal reporter. With the addition of GSH, the MnO will be dissolving detaching CTC molecules from the surface of Au@MnO and resulting in a signal-off off SERS response and indirect and sensitive detection of GSH could be realized. The limit of detection of GSH by SERS method is as low as 0.1 μmol/L and a good linear relationship of GSH is found in the range from 0.5 to 30 μmol/L. Au@MnO-SERS assay is successfully applied to detect cellular GSH, which is validated by using Enzyme-linked-immunoassay-based Kit. The Au@MnO-SERS protocol has promising potential for clinical application.