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

Kentaro Yoshida,Tetsuya Ono,Katsuhiko Sato,Yoshitomo Kashiwagi,Takenori Dairaku

doi:10.3390/nano8110941

Abstract

H2O2-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 H2O2. H2O2-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 H2O2. The mechanism of nanofilm decomposition was thought that more reactive oxygen species (ROS) was formed by reaction of hemin and H2O2 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 H2O2, modification ratio of hemin, pH, and ionic strength.

Highlights

Functional multilayer thin films have recently been prepared by a layer-by-layer (LbL) deposition technique through electrostatic interaction of polycation and polyanion [1,2]
In this work we report the H2O2-induced decomposition of LbL nanofilms composed of hemin-appended poly(ethyleneimine) (H-PEI) and DNA
It is reasonable that H-PEI and DNA form the H-PEI/DNA film, because PEI and DNA could bind through the electrostatic interaction (PEI and DNA are polycation and polyanicon, respectively)

Summary

Introduction

Functional multilayer thin films have recently been prepared by a layer-by-layer (LbL) deposition technique through electrostatic interaction of polycation and polyanion [1,2]. Synthetic polymers [3,4], proteins [5,6,7], DNA [8,9], and polysaccharides [10,11] have been used for preparing LbL nanofilms. Such layered thin films have found application in biosensors [5,6,7], separation and purification [12,13], controlled release of drugs [14,15,16], and polyelectrolyte microcapsules [17,18,19].

Apparatus

Preparation of Nanofilms

Decomposition of Nanofilms

Observation of Nanofilms with AFM

Results and Discussion

Conclusions