Plasmonic nanobiosensor based on hairpin DNA for detection of trace oligonucleotides biomarker in cancers.

MicroRNAs (miRNAs), a class of small, endogenous, noncoding RNA molecules, can serve as biomarkers for potential applications in cancer diagnosis, prognosis, and prediction due to its abnormal expression. As a result, a novel label-free biosensor with nanometer scale was prepared and employed in the detection of trace oligonucleotides based on the localized surface plasmon resonance (LSPR). The dielectric constant on the surface of DNA modified gold nanoparticle would change when probe single-strand DNA hybridized with target oligonucleotides, which resulted in the notable red shift of scattering peak position. The biosensor with excellent selectivity can be used in a real-time monitoring hybridization process. Notably, this method provided label-free detection of DNA and miRNA at single nanoparticle level with limit of detection up to 3 nM. Due to the advantages of LSPR scattering spectra, single nanoparticle biosensor can be designed for trace cancer-relevant miRNAs detection in the future.