Monodispersed silver-gold nanorods controllable etching for ultrasensitive SERS detection of hydrogen peroxide-involved metabolites.

Hydrogen peroxide (H2O2)-involved metabolites are widely engaged in cellular metabolism, and play significant roles in cell proliferation, cell growth, and signaling transduction. It is highly desirable to establish a method for the detection of H2O2-involved metabolites for applications ranging from chemical sensing to biomedical diagnosis. Herein, monodispersed sandwich Au@4-MBN@Ag@PEG nanorods (referred to as AMPRs) with bright Raman emission were developed to serve as a universal platform for detecting H2O2-involved metabolites (4-mercaptobenzonitrile is abbreviated to 4-MBN as the Raman reporter and PEG is polyethylene glycol). The system detects metabolites through changes in the surface-enhanced Raman scattering (SERS) spectrum, resulting from the controllable etching of the silver layer by the H2O2 produced by the metabolites. The integrative nanoplatform was successfully used to quantify the levels of glucose, lactate, and choline in aqueous solutions by exploiting the close linear relationship between the intensity of a SERS band and the logarithmic concentration of H2O2. The presented SERS nanoplatform demonstrated considerable practicability for the detection of glucose in cerebrospinal fluid samples (with a limit of detection (LOD) of 1.76 μM), and was capable of distinguishing infected from uninfected individuals. Therefore, the SERS sensor provides a new platform for the detection of H2O2-involved metabolites in biological fluids, and has potential for use in metabolite analysis and biomedical diagnostics.