ELECTROCHEMICAL DNA SENSORS BASED ON POLYMERIC INDICATOR: USE OF A POLY(4-VINYLPYRIDINE) DERIVATIVE BEARING Os(5,6-5,6-dimethyl-l,10-phenanthroline)_2Cl~(2+)

摘要

A poly(4-vinylpyridine) (PVP) derivative bearing redox-active osmium complexes, PVP-[Os(5,6-dmphen)_2Cl]~(2+) (5,6-dmphen = 5,6-dimethyl-l,10-phenanthroline), was employed as a hybridization indicator for electrochemical DNA sensors. PVP-[Os(5,6-dmphen_2Cl]~(2+) exhibited -1000 times higher sensitivity than the corresponding monomeric analogue, [Os(5,6-dmphen)_3]~(2+), in DNA determination due to polymeric effects. The detection limit of the present sensor was 0.1 pM. Another merit of the polymeric indicator is that the redox potential was found to be +360 mV (vs Ag/AgCl), which is significantly lower than that reported for the monomeric analogue (+672 raV). The polymeric indicator was applicable to the discrimination of single- and double-base-mismatched DNAs from fully matched target DNA. The polymeric indicator can be removed from the electrode surface by rinsing the electrode in a high-temperature buffer for 6 min, and thus, the polymeric indicator-based DNA sensor, can.