Gold electrodes modified with poly (4-aminophenol): incorporation of nitrogenated bases and an oligonucleotide

BACKGROUND: Investigations of chemical modification of electrode surfaces and immobilization of nitrogenated bases and oligonucleotides are considered essential for the construction of DNA electrochemical nanodevices. Modification of gold electrode surfaces with poly(4-aminophenol) was carried out in order to produce polymers capable of immobilizing purine bases and oligonucleotides. RESULTS: Gold electrodes coated with poly(4-aminophenol) showed improved analytical characteristics and considerably enhanced the electrochemical signals associated with the detection of adenine and guanine by factors of ca 3 and ca 6, respectively, when compared with non-coated gold surfaces. Impedance studies indicated higher charge transfer impedance to modified electrodes containing adenosine monophosphate. Atomic force microscopy images showed that nitrogenated bases have a strong influence over the morphology of the modified electrode surface. It was observed that the modified electrode containing guanine presents globular morphology. CONCLUSION: The modified electrodes increased the amplitude of the current signal of nitrogenated bases when compared to non-coated gold surfaces and produced good response and peaks to the detection of an oligonucleotide. This work presents, for the first time, the electropolymerization of 4-aminophenol on gold electrodes, as well as the detection of nitrogenated bases and an oligonucleotide incorporated on these modified electrodes. (c) 2007 Society of Chemical Industry.