An electrochemical determination method for the analyzing sequence-specific DNA using ferrocene-capped gold nanoparticles/streptavidin conjugates has been developed in this work. Thiolated DNA probes were covalently immobilized on a gold electrode with hexanethiol (HT) forming mixed self-assembled monolayer and hybridized with target DNA, containing a complementary sequence. Duplex (Double-stranded) DNA was formed on the gold surface. Then functional gold nanoparticles were introduced via strong interaction...