Detection of human interleukine-2 gene using a label-free electrochemical DNA hybridization biosensor on the basis of a non-inosine substituted probe

The human interleukine-2 gene (hIL-2) is detected with a label-free DNA hybridization biosensor using a non-inosine substituted probe. The sensor relies on the immobilization of a 20-mer antisense single strand oligonucleotide (chIL-2) related to the human interleukine-2 gene on the pencil graphite electrode (PGE) as a probe. The guanine oxidation signal was monitored using anodic differential pulse voltammetry (ADPV). The electrochemical pretreatment of the polished PGE at 1.80 V for 5 min is suggested. Then, 5 min immobilization at 0.50 V was found as the optimum condition for immobilization of the probe. The electrochemical detection of hybridization between chIL-2 and hIL-2 as a target was accomplished. The selectivity of the biosensor was studied using noncomplementary oligonucleotides. Diagnostic performance of the biosensor is described and the detection limit is found 36 pg/mu L,