Electrochemical DNA sensor based on electropolymerized 2,3-diaminophenazine for detection of intercalative DNA damage in presence of copper ions

The electrochemical parameters of 2,3-diaminophenazine (DAP) and its polymeric form (PDAP) electrodeposited from the perchloric acid on the screen-printed carbon electrodes (SPCE) were investigated. The electropolymerized PDAP coating was used with native DNA from various sources (calf thymus, salmon sperm, herring sperm, chicken erythrocytes) for the DNA sensor assembly. The layer-by-layer assembly of the DNA sensor was controlled by voltammetric and impedimetric measurements. The influence of DNA immobilization conditions (pH value, concentration, incubation time, DNA immobilization procedure) were tested to choose the optimal assembly protocol. The SPCE/PDAP/DNA sensor was used for qualitative DNA damage discrimination by anticancer drugs in absence and in presence of copper ions. The wide range of anthracycline drugs (doxorubicin, daunorubicin, valrubicin, idarubicin, epirubicin, pirarubicin) and antimetabolite drug mitoxantrone were tested as intercalative agents. It has been shown that addition of mannitol as a radicals’ scavenger to the mixture of doxorubicin and copper ions neutralize the reactive oxygen species generated. The structure of drug, its intercalation ability and affinity to copper ions have affected the interaction with DNA. To evaluate the intercalation and concomitant secondary DNA damage by reactive oxygen species, two coefficients (Kint and KSD) was proposed. The sensor developed can be applied in the medical investigations of novel anticancer drugs.