Individual Au-Nanocube Based Plasmonic Nanoprobe for Cancer Relevant MicroRNA Biomarker Detection.

MicroRNA205 (miR-205), as a significant tumor biomarker, is of vital importance for diagnosis of lung cancer and its overexpression patterns have been extensively studied. Here, we report a novel and label-free nanoprobe with high sensitivity and selectivity for miRNA biomarker detection using localized surface plasmon resonance (LSPR) technology on a single DNA modified gold nanocube (AuNC). This method allowed real-time monitoring of the subtle LSPR scattering peak position's change which was aroused by the variation of dielectric constant in the hybridization process of target miRNA with ssDNA modified on the surface of AuNCs. Notably, the limit of detection of the AuNC-ssDNA probe is up to 5 pM in serum sample, and these results showed that the square structure has more superior sensitivity for design and development of nanoprobe for trace lung cancer relevant miRNAs detection. The better sensing ability and stability of LSPR probe on a AuNC provide potential application to developing a high flux biochip in the future.