Sex determination based on amelogenin DNA by modified electrode with gold nanoparticle.

We have developed a simple and renewable electrochemical biosensor based on carbon paste electrode (CPE) for the detection of DNA synthesis and hybridization. CPE was modified with gold nanoparticles (AuNPs), which are helpful for immobilization of thiolated bioreceptors. AuNPs were characterized by scanning electron microscopy (SEM). Self-assembled monolayers (SAMs) of thiolated single-stranded DNA (SH-ssDNA) of the amelogenin gene was formed on CPE. The immobilization of the probe and its hybridization with the target DNA was optimized using different experimental conditions. The modified electrode was characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The electrochemical response of ssDNA hybridization and DNA synthesis was measured using differential pulse voltammetry (DPV) with methylene blue (MB) as an electroactive indicator. The new biosensor can distinguish between complementary and non-complementary strands of amelogenin ssDNA. Genomic DNA was extracted from blood and was detected based on changes in the MB reduction signal. These results demonstrated that the new biosensor could be used for sex determination. The proposed biosensor in this study could be used for detection and discrimination of polymerase chain reaction (PCR) products of amelogenin DNA.