Electrochemical Behavior of Calcein and the Interaction Between Calcein and DNA

The electrochemical behavior of calcein (CA) has been investigated by using a conductive carbon black paste electrode (CCBPE) as working electrode. It exhibits a single well-defined redox peak in phosphate buffered saline in the range of pH 5.58.0, which attributes to the irreversible oxidation with 2 electrons and 2 protons participation. Under the optimized analytical conditions, the proposed linear sweep voltammetry (LSV) method allows the determination of CA in a linear concentration range of 0.649.60 mu M, with a limit of detection of 0.32 mu M. Further, the interaction between CA and DNA were studied by voltammetric and spectrometric methods. Both studies have shown that CA can bind to DNA by the intercalation binding mode. Under the present experimental condition, the binding constant beta of CA and dsDNA is 1.10X107. Meanwhile, in the loop-mediated isothermal amplification (LAMP) reaction mixture there is obvious interaction between CA and dsDNA, resulting in a nonignorable decrease of the indicating sensitivity.