Impedimetric Detection of Hairpin Ribozyme Activity

Electrochemical impedance spectroscopy is successfully utilized for label-free monitoring of the cleavage reaction of a RNA substrate by a complementary hairpin ribozyme. The formation of the RNA substrate/ribozyme complex is increasing the negative charge at the interface and is modulating the kinetic of the redox conversion of a negatively charged redox mediator (e.g. [Fe(CN)(6)](3-/4-)) hence leading to an increase in the charge transfer resistance. Upon addition of bivalent cations such as Mg2+ ions the conformation of the ribozyme is changed and the catalytic cleavage of the RNA is monitored by a decrease of the charge transfer resistance.