A voltammetric method for the determination of surface-confined wild-type p53 protein has been developed. Consensus double-stranded oligonucleotide (ds-DNA) was first formed onto gold electrodes via hybridization of thiolated single-stranded DNA (ss-DNA)/hexanethiol (HT) mixed self-assembled monolayer with the complementary target DNA. The resultant consensus ds-DNA was subsequently used to capture wild-type p53 in solution. The cysteine residues on the exterior of the p53 molecules were derivatized with a thiol-specific reagent, N-(2-ferrocenylethyl)maleimide (Fc-Mi). Well-defined voltammetric peaks that report on the interaction of p53 with the consensus ds-DNA were obtained. The level of p53 binding was found to be dependent on the sequence of the double-stranded (ds-DNA). The present method can measure p53 concentration as low as 1.33 nmol•L－1.

Key words: p53, consensus double-stranded DNA, N-(2-ferrocenylethyl)maleimide, voltammetry