In-situ photoelectrochemical surface-enhanced Raman scattering based on Au@Ag/WO3 hollow microsphere for dual-mode sensing of microcystin-LR

Abstract

Developing an accurate assay for early warning of microcystin-LR (MC-LR) is of great importance for environmental protection and agricultural production. Herein, this paper reported an in-situ photoelectrochemical surface-enhanced Raman scattering (PEC-SERS) strategy for dual-mode detection of MC-LR. The Au@Ag core-cell nanoparticles loaded hollow WO3 microsphere (Au@Ag/H-WO3) acted as in-situ PEC-SERS substrate to take advantage of the synergy between electromagnetic and chemical enhancement, while methylene blue (MB) was chosen as a bifunctional probe to produce photocurrent and SERS signal. For this strategy, double signals from MB were simultaneously induced by a 532 nm laser that the SERS signal and photocurrent offered a 57.9-fold and a 4.7-fold amplification, respectively, in the presence of Au@Ag/H-WO3. For analysis, the binding of MC-LR to aptamer led to the stripping of MB from the substrate and further decreased signals. Such a strategy offered linear ranges of 0.3–50 ng/mL in PEC mode while 1–100 ng/mL in SERS mode for MC-LR detection with high accuracy and applicability for real sample analysis. This in-situ PEC-SERS strategy offered an efficient way to monitor hazardous materials in the environment and agriculture.