Studies Of Electrochemical DNA Biosensor Using The Isorhamnetin As Hybridization Indicator

DNA electrochemical sensor is noted widely in recent years for rapid development, which is one of the important detective and analytic means of nucleic acid with advantage of rapid, simple, sensitive and low cost.One of the keys to a successful electrochemical biosensor is to select a sensitive hybridization indicator. This article studied the electrochemical properties of flavonoids derivatives——isorhamnetin (ISOR) which is of anticancer and antibacteria activation,and the interaction mechanism between salmon sperm DNA and ISOR, through electrochemical and UV/vis spectroscopic techniques, and ISOR as a sensitive and specific hybridization indicator for detection of PML-RARαfusion gene in acute promyelocytic leukemia.The results indicated that in our optimal conditions the binding modes of the ISOR to DNA was intercalative. Electrochemical and UV/vis spectroscopic techniques revealed that the interaction of ISOR with DNA forms a nonelectroactive supramolecular complex which results in the decrease of peak current. The UV–Vis absorption spectrums showed that slight shifts with the absorption peak decreases significantly along with slight shift after the addition of dsDNA, which also provided potent evidence for the possible intercalative binding. We determined the calculated electrochemical parameters of the binding constants of the ISOR with DNA.The binding constants of ISOR was 1.03×105.The DNA electrochemical sensor was prepared by covaltently binding the designed single-stranded PML-RARαDNA fragments on the surface of CPE together with ISOR as electroactive indicator. This sensor had the high specificity, the high sensitivity, and the low detection limits. The average current response showed excellent correlation with the amount of the complementary oligonucleotides in the range from 2.0×10-8 to 1.2×10-7 M. The regression equation was y = 0.2378 C(μM) +2.269 (x was the amount of the target DNA, mol; y was the DPV peak current of ISOR,μA), and the regression coefficient of the linear curve was 0.9973. A detection limit of 1.5×10-9 M of the target DNA can be estimated using 3σ.This article developed the new electrochemical biosensor for the first time ,which was applied to detect PML-RARαfusion gene in acute promyelocytic leukemia (APL) with obtained a satisfactory result.