We present a new electrochemical strategy to probe the binding of the anticancer drug, cisplatin, with DNA at the liquid-solid interface. The strategy exploits the sensitivity of a long-range charge transfer observed through double stranded DNA (dsDNA), utilizing "on" and "off" switching of such a charge transfer upon drug binding as the basis to probe the electronic changes that occur to the DNA upon cisplatin exposure. The charge transfer occurs when a redox active species intercalates into the dsDNA base-pair pi-stack, thereby producing a current. Disruption of the DNA base-pair stack will reduce the efficiency of the charge transfer to the redox species, therefore a diminution in the current arising from the long-range charge transfer is observed. As a result, the electrochemical technique can provide information on the disruption of the intrinsic electronic properties of the DNA duplexes, which provide a new way to study drug-DNA binding.