Sulfur source-mediated in situ growth of highly conductive nanocomposites for sensitive detection of miRNA-21

Abstract

The accurate detection of miRNA-21, one of the emerging biomarkers for breast cancer, is extremely important for facilitating early diagnosis. In this paper, we present a novel nanocomposite material Co9S8@WS2/DWCNT was prepared through a one-pot hydrothermal method. WS2 (Tungsten disulfide) semiconductor nanosheets were used as negative carriers to provide binding sites. TAA (Thioacetamide) was used as a sulfur source and cross-linking agent to modify ZIF-67 (Co-based zeolite imidazole framework) into Co9S8 with excellent electrical conductivity and to grow it in situ on the WS2 surface. DWCNT (Double-walled carbon nanotubes) was then stacked with WS2 by π-π conjugation. To further enhance the electrical conductivity and biocompatibility of the composite nanomaterials, it was doped by AgNPs (Silver nanoparticles) to obtain Co9S8@WS2/DWCNT-AgNPs nanocomposites with excellent electrochemical properties. The capture probe cDNA was immobilized on the electrode through Ag-S bonding to enable sensitive detection of miRNA-21. With a concentration response range of 10−18-10−11 M and a detection limit as low as 1.54 aM, the detection of miRNA-21 in human serum samples has been successfully achieved applying to this biosensing platform.