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 CS(2) 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)(6)(3-/4-) as a redox indicator. The hybridization of DTC-DNA with complementary target DNA could be well distinguished with the use of Co(phen)(3)(3+) as an electrochemical indicator. The fabricated electrochemical DNA biosensor could achieve a detection limit of about 0.1nM toward complementary target DNA. Also, the current strategy is readily operated with less time consumed and lower cost compared with those commonly used strategies.