A nano-biosensor based on graphene oxide (GO) and 5-carboxy fluorescein (FAM) labeled DNA was developed for the detection of deletion mutation in exon 19 of EGFR gene, which led to the lung cancer. The method is based on the adsorbtion of FAM-labeled single-stranded DNA (fDNA) on GO, leading to fluorescence quenching of FAM. By addition of its complementary DNA (cDNA), a double-stranded DNA (dsDNA) was formed, resulted in recovering of fluorescence of FAM by desorbing and releasing from GO. While in the case of mismatched DNA, corresponding dsDNA was not formed, and therefore the fluorescence of FAM was not recovered.
