Single to three nucleotide polymorphisms assay of miRNA-21 using DNA capped gold nanoparticle-electrostatic force microscopy system

Abstract

Aberrant expression of microRNA (miRNA) in biological cells is crucial evidence for early diagnosis of cancer. Improvements in molecular detection techniques enabled miRNA to be detected in human blood obtained from liquid biopsies (e.g., Polymerase chain reaction, microcantilever sensor, and surface-enhanced Raman spectroscopy). Despite the advances in molecular detection technology, a simultaneous detection of single or multiple mutations of miRNAs is still a challenge. Here, we show electrostatic force microscopy (EFM) imaging of DNA-capped gold nanoparticles (DCNP) that enables discrimination between single and three-nucleotide polymorphism (SNP, TNP): 1 and 3-point mismatched nucleotides in miRNA-21 (M1_RNA, M3_ RNA). Detection of the miRNA-21 and their mutant sequence is owing to sterically well-adjusted DNA&#8211

RNA interactions that take place within the confined spaces of DCNP. The average absolute EFM amplitudes of DCNP interacting with M1_RNA, and M3_RNA (&#8722

81.0 ± 11.5, and &#8722

65.7 ± 8.2 mV) were found to be lower than the DCNP reacting with normal (non-mutant) miRNA-21 (&#8722

100.2 ± 13.6 mV).