Preparation of Hydrogen Peroxide Sensitive Nanofilms by a Layer-by-Layer Technique

H(2)O(2)-sensitive nanofilms composed of DNA and hemin-appended poly(ethyleneimine) (H-PEI) were prepared by a layer-by-layer deposition of DNA and H-PEI through an electrostatic interaction. The (H-PEI/DNA)(5) film was decomposed by addition of 10 mM H(2)O(2). H(2)O(2)-induced decomposition was also confirmed in the hemin-containing (PEI/DNA)(5) in which hemin molecules were adsorbed by a noncovalent bond to the nanofilm. On the other hand, the (PEI/DNA)(5) film containing no hemin and the (H-PEI/PSS)(5) film using PSS instead of DNA did not decompose even with 100 mM H(2)O(2). The mechanism of nanofilm decomposition was thought that more reactive oxygen species (ROS) was formed by reaction of hemin and H(2)O(2) and then the ROS caused DNA cleavage. As a result (H-PEI/DNA)(5) and hemin-containing (PEI/DNA)(5) films were decomposed. The decomposition rate of these nanofilms were depended on concentration of H(2)O(2), modification ratio of hemin, pH, and ionic strength.