Babes-Bolyai University of Cluj-Napoca, Faculty of Chemistry and Chemical Engineering, Physical Chemistry and Biophysics Department, 400028 Cluj-Napoca, Romania
A systematic study on the structure and properties of thin films, formed of globular protein and chitosan in the presence of gold nanoparticles, was carried out with the aim of assessing the effects of protein recognition on the nano-structuring processes within such nanocomposite films. The used techniques were FTIR, UV-Vis spectroscopy, atomic force microscopy, electron microscopy (TEM and SEM) and cyclic voltammetry. Globular protein was extracted and purified from aleurone cells of barley. Deacetilated chitosan was of high molecular weight. Both polymers were used to prepare thin films deposited on solid substrates, i.e. glass, polystyrene and quartz, by various traditional methods, including Langmuir-Blodgett technique. Gold nanoparticles of 20 to 35 nm diameter were synthesized and embedded into globular protein and chitosan films. Both nanostructure and electrochemical properties of nanocomposite films were notably different than for films cast from chitosan solution due to the protein recognition for the gold nanoparticle surfaces. Nanocomposite materials have high stability and might have industrial and medical applications, particularly for sensing devices and drug delivery systems.