A colorimetric nano-biosensor for simultaneous detection of prevalent cancers using unamplified cell-free ribonucleic acid biomarkers

Early detection of cancer increases the chance of effective treatment and survival rates. The aim of this study is to develop a rapid and non-invasive nano-biosensing method to screen common lethal cancers in their early stages. In that regard, two circulating microRNA (miR-21, miR-155) biomarkers, which are upregulated in plasma in prevalent cancers, were targeted by a rapid and colorimetric nano-biosensor based on non-crosslinking Au-nanoprobes without amplification requirement. Multiple cancerous cell lines, including A549, MCF7, HT-29, A2780, AGS, MKN-45, and SW-1736 and the primary fibroblast were examined with naked eyes after the hybridization assay using exogenous biomarkers. The results were also confirmed by spectroscopy analysis. The upregulated miRNAs in cancerous cell lines caused a significant blue shift in the Au-nanoprobe absorbance spectrum while the samples isolated from normal cells remained intact red. The limit of detection (LOD) of the method was determined to be less than one ng/µL of total isolated miRNA using an instrument-free visual method. The developed geno-sensing method could serve as a simple, point-of-care platform for cancer prognosis and diagnosis, leading to operative nano-theranostics.