Development of an electrochemical DNA biosensor with the DNA immobilization based on in situ generation of dithiocarbamate ligands

In this article, a simple and effective strategy for DNA immobilization on gold electrode surface is developed. The amine-modified oligonucleotide was firstly reacted with CS2 and then in situ generated dithiocarbamate group functionalized probe DNA (DTC–DNA) was directly attached onto the gold surface by bidentate anchoring points. The DNA biosensor fabrication process was characterized by cyclic voltammetry and electrochemical impedance spectroscopy with the use of Fe(CN)63−/4− as a redox indicator. The hybridization of DTC–DNA with complementary target DNA could be well distinguished with the use of Co(phen)33+ as an electrochemical indicator. The fabricated electrochemical DNA biosensor could achieve a detection limit of about 0.1 nM toward complementary target DNA. Also, the current strategy is readily operated with less time consumed and lower cost compared with those commonly used strategies.