Abstract
Cyclic voltammetry and differential pulse voltammetry together with electrochemical impedance spectroscopy were used for an electrochemical study of methylene blue at bare and DNA-modified silver solid amalgam electrode. Methylene blue gave a specific cathodic signal, and this signal is significantly higher at DNA-modified than at unmodified amalgam electrode, which is in correspondence with the changes of charge resistance transfer values obtained from Nyquist plots.
The integrity of dsDNA layer was tested indirectly using differential pulse voltammetry of intercalated methylene blue after the previous UV irradiation of the biosensor surface at two different wavelengths. Individual electrochemical signals depend on the time of biosensor incubation in methylene blue, time of the exposure to UV radiation, and selected wavelengths.