Square Wave Stripping Voltammetry of Unlabeled Single- and Double-Stranded DNAs
We show that, in difference to previously applied electrochemical methods working with stationary electrodes, square wave voltammetry produces well-developed peaks II(SW) (specific for dsDNA) and III(SW) yielded by ssDNA at hanging mercury drop electrode (HMDE) and solid amalgam electrodes (SAEs). Using these peaks various kinds of DNA structural transitions can be studied, including unwinding of dsDNA at negatively charged electrode surfaces. The sensitivity of the DNA analysis is much better than that obtained with guanine oxidation signals at carbon electrodes. Both carbon electrodes and SAEs appear attractive as transducers in label-free RNA and DNA sensors.