Spectral study of interaction between poly(L-lysine)-poly(ethylene glycol)-poly(L-lysine) and nucleic acids

Polymer-DNA interactions have attracted considerable interests due to their important application in DNA transfection and cellular drug delivery technologies. In this work, a new detection assay for DNA is proposed with a tri-block copolymer poly(L-lysine)-poly(ethylene glycol)-poly(L-lysine) by resonance light scattering technique with the linear ranges from 0.0656 to 6.56 μg ml⁻¹. The detection limit for DNA is 0.42 ng ml⁻¹. Most coexisting substances do not interfere in the detection. UV-spectra and FTIR-spectra were employed to demonstrate the mechanisms of the interaction that the conformation of the DNA changes because the microenvironment of DNA changes.