2.6. Hybridisation detection and methylene blue accumulation using open circuit potential Square wave voltammetry (SWV) using methylene blue as a redox molecule was employed for hybridisation detection. Methylene blue is well known to interact with single and double-strand DNA based using different modes of action. After hybridisation, a chip was immersed in 50 µM methylene blue in HEPES buffer (20 mM HEPES, 10 mM KCl, pH 7) for 10 minutes, with an applied OCP for the first five minutes to accumulate the MB. After this time, MB was washed away with HEPES buffer followed by SWV recorded between 0 and -0.8 V versus on the platinum pseudo reference electrode (frequency 75 Hz, pulse amplitude 75 mV, increment 15 mV).