INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
Hydrophobic interactions leading to a complex interplay between bioelectrocatalytic properties and multilayer meso-organization in layer-bylayer assemblies
M.L. CORTEZ; N. DEMATTEIS; M. CEOLIN; W. KNOLL; F. BATTAGLINI; OMAR AZZARONI
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
ROYAL SOC CHEMISTRY
Lugar: CAMBRIDGE; Año: 2014 vol. 16 p. 20844 - 20844
The present study explores the development of mesostructured bioelectrochemical interfaces withaccurate compositional and topological control of the supramolecular architecture through the layerby-layer assembly of ternary systems based on poly(allylamine) containing an osmium polypyridylcomplex (OsPA), an anionic surfactant, sodium dodecyl sulfate (SDS) or sodium octodecyl sulfate (ODS),and glucose oxidase (GOx). We show that the introduction of the anionic surfactant allows a sensitiveincrease of the polyelectrolyte and the enzyme uptake at pH 7.0, enhancing its catalytic behavior in thepresence of glucose as compared to the surfactant-free system (OsPA/GOx)n constructed at the samepH. Structural characterization of the multilayer films was performed by means of grazing-incidencesmall-angle X-ray scattering (GISAXS), which showed the formation of mesostructured domains withinthe composite assemblies. Experimental results indicate that the balance between ionic andhydrophobic interactions plays a leading role not only in the construction of the self-assembled systembut also in the functional properties of the bioactive interface. The structure of the ternary multilayeredfilms depends largely on the length of the alkyl chain of the surfactant. We show that surfactantsincorporated into the film also play a role as chemical entities capable of tuning the hydrophobicity ofthe whole assembly. In this way, the deliberate introduction of short-range hydrophobic forces wasexploited as an additional variable to manipulate the adsorption and coverage of protein during eachassembly step. However, the integration of long-chain surfactants may lead to the formation of verywell-organized interfacial architectures with poor electron transfer properties. This, in turn, leads to acomplex trade-off between enzyme coverage and redox wiring that is governed by the mesoorganizationand the hydrophobic characteristics of the multilayer assembly.