Introducing curcumin as an electrochemical DNA hybridization indicator and its application for detection of human interleukin-2 gene

In this paper, the application of curcumin (CU) as a non-toxic electrochemical DNA hybridization indicator was described. Hybridization investigations on a pencil graphite electrode surface as a transducer using oligonucleotides containing only one base type, including poly A, poly T, poly C, and poly G as probe and as related complementary/non-complementary sequences, showed that CU has no specific interaction with each of the oligonucleotides of DNA. Furthermore, results showed good interaction between CU and the hybridized form of oligonucleotides; thus, the extent of hybridization was evaluated based on the difference between differential pulse voltammetry (DPV) signals of CU accumulated on the probe-pencil graphite electrode (PGE) and CU accumulated on the probe-target-PGE. Then, the developed biosensor was successfully applied for the detection of short sequences of human interleukin-2 (hIL-2) gene as a model. A hybridization experiment with non-complementary oligonucleotide showed that the suggested DNA sensor responds selectively to the target. At optimized conditions, two linear ranges were obtained for hIL-2 gene, first from 50 to 1000 pM and second from 0.01 to 1 μM with a detection limit of 12 pM. 7.0) containing 20 mM NaCl.