A facile approach for fabrication of three-dimensional platinum-nanoporous gold film and its application for sensitive detection of microRNA-126 combining with catalytic hairpin assembly reaction

Abstract MicroRNAs (miRNAs) as important biomarkers are closely related to cancers. Herein, a easy-facilitative nanocomposite which consists of Pt nanoparticles (PtNPs) and nanoporous gold (NPG) structure has been successfully prepared on Au electrode through a facile two-step square wave voltammetry (SWV) combining with electrodeposition method. Scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and cyclic voltammetry (CV) were used for microscopic analysis and electrochemical studies of the PtNPs/NPG modified electrode. Combined with the well-designed catalytic hairpin assembly (CHA) amplification strategy, the small amount of Pt particles presented over the NPG film electrode substantially improved the electrocatalytic activity in the determination of microRNA-126 (miRNA-126), and a significant increase of amperometric current response accompanied with low background signal could be monitored at PtNPs/NPG electrode compared to those of bare Au and NPG electrodes. Under optimal conditions, a wide linear range of 0.5 to 500 pM for the amperometric assay of miRNA-126 was achieved along with a limit of detection (S/N=3) of 0.17 pM. We further applied this assay to detect target miRNA in the total RNA extract of H1975 cells. Therefore, the proposed biosensing platform exhibits good analytical performance such as facile, ultrasensitive, low-cost, and high anti-interference capability, which promises to be a potential and beneficial tool for biomedical research and early clinical diagnosis of cancers through detection of multiple miRNA biomarkers.