A novel SERS substrate with high reusability for sensitive detection of miRNA 21

Electrochemistry combining with Surface Enhanced Raman Spectroscopy (EC-SERS) is a hot area which can achieve real-time analysis of the electrochemical product. In this work, a high-performance reusable Raman substrate was fabricated via electrochemical reduction for miRNA 21 assay. In this strategy, 2'-hydroxymethyl-3, 4-thylenedioxythiophene (EDOT-OH) was electropolymerized to form PEDOT-OH (Red), which acted as a part of SERS substrate and a Raman probe at the same time. The Raman intensity of PEDOT-OH was different between the reduction (Red) and oxidation state (Ox). When it is oxidized, the signal of the PEDOT-OH (Ox) on the electrode surface can be restored by applying a reduction voltage. In view of this feature, a Raman enhanced substrate displaying signal changes is constructed and the constructed Raman substrate can be recycled quickly and efficiently. Combining with double-amplification strategy, the SERS platform can detect miRNA 21 from 100 fM to 1 μM. The Raman substrate can be reused at least 15 times and solves the current problems of poor reusability and troublesome restoration of present reusable Raman substrate. As a result, it indicates that the reusable Raman substrate with high performance and non-destructive property will broaden the application of EC-SERS and SERS analysis.