Development of the BAT-26 mutation-based electrochemical genosensor for identifying microsatellite instability in relationship to cancer

Screening for microsatellite instability is one of the biggest challenges in the cancer diagnosis due to its association with different types of cancer development. In this sense, the development of fast and highly sensitive analytical devices for early the cancer detection is a high priority. In the present work, a highly sensitive electrochemistry genosensor is developed and described for BAT-26 mutation detection using: differential pulse voltammetry (DPV), and cyclic voltametric (CV) supported by scanning tunnel microscopy (STM). The redox reaction of Fe(CN)63−/4– was monitored to probe the presence DNA target. The results demonstrate that modifying the screen-printed gold electrode surface (SPGE) 250AT with a combination of 11-mercaptoundecanoic acid (MUA) and a single-stranded DNA oligonucleotide successfully altered the electrode's properties, particularly its affinity for detecting the BAT-26 mutation under physiological conditions. The genosensor exhibited a wide linear range (100 aM to 1 μM) and achieved a low detection limit of 71.74 aM under optimal parameters. These characteristics, coupled with its high sensitivity and rapid analysis time, make it a promising candidate for development into a portable microsatellite instability diagnostic kit.