The interaction of water-soluble P-(N,N-dimethylaminomethyl)-calix[8]arene(CX8)with calf thymus DNA was studied using neutral red(NR) as a probe by uv-vis spectroscopy.The effect factors such as the pH of solution and ionic strength on the spectra were also investigated.The interaction mechanism was proposed.The results show that the strong electrostatic interaction between DNA and CX8 existed,on the one hand,the oxyphosphate anion of DNA can be neutralized by CX8 partally,which induced the contraction of DNA and the conformational change of DNA,which led to release NR from NDA partially.On the other hand,the CX8 can also compete the electrostatic sites with NR directly.
