Studies on the interactions between bovine beta-lactoglobulin and chitosan at the solid-liquid interface

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Jose M Campina (Author) Other; Hileia K. S. Souza (Author) FEUP; Joao Borges (Author) Other; Martins, A (Author) Other; Maria do Pilar Gonçalves (Author) FEUP; Silva, F (Author) FCUP

Journal

Title: Electrochimica Acta

Vol. 55

Pages: 8779-8790

ISSN: 0013-4686

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 15 Citations

Scopus - 16 Citations

Other information

Authenticus ID: P-003-0EH

DOI: 10.1016/j.electacta.2010.08.012

Abstract (EN): Chitosan ultrathin films have been formed on polycrystalline Au substrates using the LbL technique with the purpose of studying its interaction with bovine beta-lactoglobulin (beta-LG) at the solid-liquid Interface The immobilization of chitosan was followed by Quartz Crystal Microbalance with energy dissipation (QCM-D) Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) The behavior of the chitosan films in the presence of beta-LG solutions with different bulk concentrations ([beta-LG]) ionic strength (I) and pH has been investigated using the same techniques plus Atomic Ewe Microscopy (AFM) The results showed that for pHs lower than protein s pI weak intermolecular forces (H bonding Van del Waals hydrophobic etc) are established between beta-LG and chitosan (especially close to the pI) leading to low coverage nonspecific adsorption On the contrary when pH > pI strong ionic bonding through attractive electrostatic interactions lead to high coverage adsorbed phases composed of large beta-LG aggregates The adsorption process was shown to consist of a relatively fast step (in which these interactions are predominant) which is followed once the beta-LG monolayer is exceeded by the slow formation of thicker and increasingly viscoelastic films through beta-LG self-aggregation QCM-D and AFM experiments unveiled the role of [beta-LG] and I on the formation of these aggregates The adsorption isotherm built from impedance data in the medium-low [beta-LG] range (0 001-0 3 mg m L-1) showed good fitting to the Langmuir model confirming that the formation of one beta-LG monolayer is achieved in this concentration range

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12