Effect of the Polycation Nature on the Structure of Layer-by-Layer Electrostatically Self-Assembled Multilayers of Polyphenol Oxidase

ERICA S. FORZANI; MANUEL LÓPEZ TEIJELO; FRANCISCO NART; ERNESTO J. CALVO; VELIA M. SOLÍS

BIOMACROMOLECULES

AMER CHEMICAL SOC

Año: 2003 vol. 4 p. 869 - 869

1525-7797

p style="MARGIN: 0cm 0cm 0pt; mso-layout-grid-align: none" class="MsoNormal">Self-assembled multilayers comprised of alternate layers of polyphenol oxidase (PPO) and poly(allylamine) (PAH) or PPO and poly(diallyldimethylamine) (PDDA), deposited on a 3-mercaptopropanesulfonic acid (MPS)-modified gold surface, were studied ?in-situ? (under water) by means of ellipsometry and quartz crystal microbalance (QCM), and ?ex-situ? (in open air) by ellipsometry and fourier transform infrared reflection-absorption spectroscopy (FT-IRRAS). Optical ellipsometric properties of (PAH)n(PPO)n and (PDDA)n(PPO)n multilayers were obtained at two wavelengths, employing an isotropic single-layer model with the substrate parameters measured after thiol adsorption. Film thickness as well as ellipsometric mass values based on the de Feijter equation were also evaluated. The quartz crystal impedance analysis showed that self-assembled multilayers behaved as acoustically thin films, a