The study of small drug molecules interacting with nucleic acids is an area of intenseresearch that has particular relevance in our understanding of relative mechanismin chemotherapeutic applications and the association between genetics (includingsequence variation) and drug response. In this contribution, we demonstrate howthe sequence-specific binding of an anticancer drug Dacarbazine (DTIC) to singlebase (A-G) mismatch could be sensitively detected by combining electrochemicaldetection with biosensing surface based on gold nanoparticles. The study of small drug molecules interact with nucleic acids is an area of ​​intense research that has particular relevance in our understanding of relative mechanismin chemotherapeutic applications and the association between genetics (including sequence effects) and drug response. In this contribution, we demonstrate how the sequence-specific binding of an anticancer drug Dacarbazine (DTIC) to single base (AG) mismatch could be sensitively detected by combining electrochemical discharge with biosensing surface based on gold nanoparticles.