Electrochemical Investigation of Heterogeneous Affinity Behaviour of Methylene Blue and G‐quadruplex

Abstract The heterogeneous binding behaviour between methylene blue (MB) and G‐quadruplex, one kind of single‐stranded (ss) DNA with specific guanine tetrads, has been thoroughly studied via electrochemical techniques. Positively charged MB interacted electrostatically with both G‐quadruplex and normal ssDNA but the binding and dissociation kinetics between them were significantly different. Compared with ssDNA, G‐quadruplex had a slower binding rate constant and dissociation rate constant with MB since there existed other different binding mechanisms between G‐quadruplex and MB besides electrostatic interaction. This work might provide valuable information in the design and development of DNA sensors.