Detection of the p53 Gene Mutation Using an Ultra-sensitive and Highly Selective Electrochemical DNA Biosensor

The p53 gene- "the guardian of the genome"-is responsible for maintaining the integrity of the genome, along with cell cycle regulation, apoptosis, and cell differentiation. New analytical devices are needed to recognize the main alterations this gene could suffer, since it is one of the most frequent in human cancer. For this reason, we developed an electrochemical DNA biosensor with high sensitivity and specificity to monitor the 175p2 mutation of the p53 gene. We modified a screen-printed gold electrode (SPGE) by immobilizing a thiolated DNA probe sequence with 11-mercaptoundecanoic acid to detect its complementary sequence through the hybridization reaction. Doxorubicin (Dox) was used to increase the sensitivity of the biosensor, and the entire process was evaluated using the Cyclic Voltammetry (CV) technique. The measurement range of the developed device is from 1 fM to 100 nM of the p53 gene mutation with a limit of detection (LOD) of 2.2 fM. In the presence of Dox, the LOD increased up to 175 aM, becoming one of the highest efficiency devices in the field. The electrochemical DNA biosensor selectively detects the p53 suppressor gene mutation; it distinguishes between different non-complementary and complementary sequences. Our results indicate a high potential of our sensor for the p53 gene 175p2 mutation detection, which is convenient in the early diagnosis of diseases related to this gene.