Studies Of The Interaction Of Small Molecular Complexes With DNA And Its Application

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 advantedge of rapid,simple,sensitive and low cost.One of the keys to a successful electrochemical biosensor is to select of a sensitive hybridization indicator. This article studied of the interaction between salmon sperm DNA and three anthraquinone derivatives with antibacterial effects of aloe-emodin, rhein and alizarin using electrochemical and UV/vis spectroscopic techniques, and screened aloe-emodin(AE) out of them 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 three anthraquinone derivatives to DNA were intercalative. We determined the binding constants of the three anthraquinone derivatives with DNA. The calculated electrochemical parameters transfer coefficientαand standard electron transfer rate constant ks revealed that the interaction of aloe-emodin, rhein and alizarin with DNA forms a nonelectroactive supramolecular complex which results in the decrease of peak current, respectively. The UV–Vis absorption spectrums showed that slight shifts with the absorption peak decreases significantly after the addition of dsDNA to aloe-emodin, rhein and alizarin solutions, which also provided potent evidence for the possible intercalative binding. The binding constants of aloe-emodin, rhein and alizarin were (2.7±0.2)×10⁵,(2.1±0.4)×10⁵å’Œ(1.5±0.2)×10⁵M^-1, respectively.The DNA electrochemical sensor was prepared by covaltently binding the designed single-stranded PML-RARαDNA fragments on the surface of GCE electrode together with AE as electroactive indicator. This sensor had the high specificity, the high sensitivity, the low detection limits. The average current response showed excellent correlation with the amount of the complementary oligonucleotides applied over the range from 1.5×10^-8 to 1.5×10^-7 M. The regression equation was y = 0.4068x + 3.2729 (x was the amount of the target DNA, mol; y was the DPV peak current of AE,μA), and the regression coefficient of the linear curve was 0.9958. A detection limit of 6.7×10^-8 M of the target DNA can be estimated using 3σ.This article developed for the first time the new electrochemical biosensor for detection of PML-RARαfusion gene in acute promyelocytic leukemia (APL), which had obtained a satisfying result.