Studies of the interaction between Aloe-emodin and DNA and preparation of DNA biosensor for detection of PML-RARalpha fusion gene in acute promyelocytic leukemia

The interaction of Aloe-emodin (AE) with salmon sperm DNA in 0.1M Tris-HCl buffer (pH 4.4) and at the DNA-modified glassy carbon electrode (GCE) was systemically studied with voltammetry and ultraviolet-visible (UV-vis) spectroscopy. AE had excellent electrochemical activity on the GCE with a couple of redox peaks. We propose that AE can intercalate into DNA strands forming a nonelectroactive complex, which results in the decrease of the reduction peak current of AE. The Langmuir adsorption constants of AE at ss- and dsDNA/GCE were (2.1+/-0.4)x10(5) and (2.7+/-0.2)x10(5)M(-1), respectively. The difference between AE at ss- and dsDNA has been used for the preparation of a sequence-specific DNA electrochemical biosensor for detection of PML-RARalpha fusion gene in acute promyelocytic leukemia (APL) with a detection limit of 6.7x10(-8)M and a linear range from 1.5x10(-8) to 1.5x10(-7)M. The selectivity of ssDNA-modified electrode was also described.