Entropy-Driven Proximity Strand Displacement Amplification Strategy for Electrochemical Sensing of Cancer-Related MiRNA

Enzyme-free signal amplification is appealing for its features of robust and versatile designs, exceptional stability, and tolerance to complicated conditions. However, relatively lower amplification efficiency and slower reaction kinetics limit its wide applications. In this study, we introduce an entropy-driven proximity strand displacement amplification strategy for highly sensitive analysis. Although no enzymes participate in the reactions, multicycle strand displacements by the proximity-dependent recognition principle facilitate fast and efficient DNA structural transition. The subsequently loaded silver nanoparticles (AgNPs) provide intense stripping signals for quantitative analysis. Compared with traditional strand displacement amplification strategies, the proximity design achieves autocatalytic reactions without extra fuel strands and the integrated AgNPs exert ultrahigh sensitivity. This method exhibits improved accuracy in challenging cancer-related miRNA, which may have great potential in disease diagnosis.