Exploring the Mechanism of the Electrostatic Denaturation of Double-Stranded DNA

Electrostatic melting is an electrochemical tool that can be used to analyze the stability of DNA, allowing for the detection of various mutations in double-stranded DNA (dsDNA). Here, we explore the influence of electrostatic double layer formation on the unzipping of dsDNA to better comprehend the mechanism of this process. Previous studies by our lab show that the melting curve produced can distinguish between fully complementary 34-bp strands and a version of the same sequence in which one base pair has been replaced with a mismatch pair or detect and characterize the crosslinking of the dsDNA by anticancer drug cisplatin. Additionally, other papers in this field show that when the potential on the electrode is alternated between an attractive and repulsive potential at a set frequency, the ions in solution cannot react quickly enough to form the double layer at frequencies higher than 10 kHz. From this, we concluded that replacing the standard melting step with a fast potential pulse routine, which alternates between potentials above and below the threshold potential for melting, could give better insight into electrostatic DNA melting and its dependence on the formation of the double layer. The results of this research show that the time taken for melting to occur (τ) remained constant regardless of frequency. This implies that the mechanism is not dependent on the generation of the electric field caused by electrostatic double layer formation and that the mechanism is not purely electrostatic. Further testing proved that neither thermal melting nor probe desorption is responsible for the loss of signal used to indicate the quantity of DNA adhering to the electrode surface