An Amphiphilic Polymer- and Carbon Nanotube-Modified Indium Tin Oxide Electrode for Sensitive Electrochemical DNA Detection with Low Nonspecific Binding

We herein report an amphiphilic polymer-, carboxylated multiwalled carbon nanotube (CNT)-, silane polymer-, and streptavidin-modified indium tin oxide (ITO) electrode that allows low nonspecific binding and efficient immobilization of DNA, along with good electrocatalytic activities and low background-current levels. The low nonspecific binding results from the well-covering of the CNT and ITO surface with the amphiphilic polymer and silane polymer, as well as the poly(ethylene glycol) groups of the polymers. The streptavidin for DNA immobilization is covalently attached to the carboxylic acid groups of the amphiphilic polymer and CNT. A low surface coverage of CNT on the ITO electrode provides the good electrocatalytic activities and low background-current levels. The fabricated electrode enables us to achieve a detection limit of 100 pM in DNA detection.