Sensitive detection of miR-9 in human serum: An electrochemical approach utilizing robust gold nanostructures for early diagnosis of lung cancer

Abstract

The complexity of procedures, concentration dependency, and time consumption associated with traditional microRNA analysis platforms render them unsuitable for point-of-care (POC) diagnostics. In order to address the challenges posed by reduced electro activity resulting from the use of surfactants or stabilizers in the fabrication of nanostructures for biosensors, we have developed a customized method for gold nanofabrication. This technique involves the deposition of gold nanostructures (Au-NS) onto FTO electrodes without the use of surfactants or stabilizers, followed by the immobilization of thiolated ssDNA onto the substrate surface. To assess the performance of the resulting biosensor, we hybridized miR-9 with the ssDNA and determined the linear detection range to be from 10 zM to 100 nM. Our approach provides a unique solution to the limitations associated with electrochemical and/or SERS biosensors and demonstrates the potential for improved biosensing applications. The acquired data demonstrate the superior ability of nanostructured biosensors for label-free detection of miR-9 at attomolar limit of detection (LOD = 0.012 aM). The HRSEM data also revealed a unique nanostructure; the AFM topology confirmed an increase in the surface area aspect ratio features; and the GIXRD analysis approved the fabricated AuNSs on FTO electrodes. Furthermore, electrochemical analysis of AuNS’ platforms showed considerable electroactivity compared to bare FTO. In addition to its previously demonstrated performance, our biosensor exhibited outstanding selectivity in the detection of miR-486. The use of AuNSs in our biosensor fabrication results in excellent selectivity, high electroactivity, and ease of fabrication, rendering it an ideal option for both biosensing and cancer screening applications.