▎ 摘　　要

A facile strategy has been constructed for the highly efficient discrimination of single nucleotide polymorphisms (SNPs) based on magnetic functionalized graphene oxide (GO@Fe3O4) modified poly(dimethylsiloxane) microchip system coupled with electrochemical detection. A methylene blue-labeled single stranded DNA (P1) can complete complementary with target mircoRNA-21 (T1) to form a perfectly matched DNA/RNA heteroduplex (P1T1), while the hybridization of the P1 with single-base mismatched sequence of mircoRNA-21 (M1) can form a loose DNA/ms-RNA heteroduplex (P1M1). The pi-stacking interaction between the loose DNA/ms-RNA heteroduplex and the GO is much stronger than that of the perfectly matched DNA/RNA heteroduplex. Moreover, GO can enhance the unwinding of unstable DNA/ms-RNA through strong interaction between GO and single stranded DNA (ssDNA) and consequently increase the retention time of single-base mismatch microRNA-21 in the GO@Fe3O4-based microchip system. Therefore, the GO@Fe3O4-based microchip system exhibited high performance for the separation and detection of microRNA-21 and single-base mismatch microRNA-21, which provide a powerful protocol for SNPs discrimination within a short analytical time. More importantly, this platform can be used for other small molecules and proteins assay in various systems by simply changing the sequence of the probe DNA. (C) 2019 Elsevier B.V. All rights reserved.