Designing a fluorescence nanobiosensor for early detection of colorectal cancer using APC and miR-21-5p probes simultaneously

APC gene in ctDNA and miR-21-5p have been proposed as potential biomarkers for cancer diagnosis. In this above study, a biosensor based on multi-walled carbon nanotube (MWCNT) and DNA probe with fluorophore FAM (6-carboxyfluorescein) to detect APC gene in ctDNA, and DNA probe with fluorophore ROX (5-carboxy-x-rhodamine ) to detect miR-21-5p, was designed to identify patients with colorectal cancer (CRC).This method is based on the adsorption and stabilization of single-stranded DNA (ssDNA) labeled with FAM and ROX on MWCNT, which leads to the quenching of the fluorescence emission of FAM and ROX. By adding their complementary DNA (cDNA), which led to the release of single-stranded DNA (ssDNA) probes from the MWCNT surface and a double-stranded DNA (dsDNA) was formed, which led to the return of FAM and ROX fluorescence emission. In this study, the sensitivity of FAM fluorophore was 50 nM (50 nM) and the sensitivity of ROX fluorophore was 25 nM (25 nM). The response time in the presence of the target strand is 12 minutes. The LOD and LOQ of DNA biosensor individually were 1.12 nM and 3.2 μM, respectively. The results of this study showed that the biosensor based on carbon nanotubes and DNA probe, in addition to existing methods, can be used as a high-sensitivity method for early detection of CRC.