Discrimination of single nucleotide polymorphisms by magnetic functionalized graphene oxide-based microchip system

Abstract

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 π-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.