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BioMed Research International
Volume 2013 (2013), Article ID 461365, 7 pages
http://dx.doi.org/10.1155/2013/461365
Research Article

Ascorbic Acid and BSA Protein in Solution and Films: Interaction and Surface Morphological Structure

Grupo de Materiais Nanoestruturados, Campus Universitário do Araguaia, Universidade Federal de Mato Grosso, 78600-000 Barra do Garças, MT, Brazil

Received 13 April 2013; Revised 20 June 2013; Accepted 20 June 2013

Academic Editor: Rita Casadio

Copyright © 2013 Rafael R. G. Maciel et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper reports on the study of the interactions between ascorbic acid (AA) and bovine serum albumin (BSA) in aqueous solution as well as in films (BSA/AA films) prepared by the layer-by-layer technique. Regarding to solution studies, a hyperchromism (in the range of ultraviolet) was found as a function of AA concentration, which suggested the formation of aggregates from AA and BSA. Binding constant, , determined for aggregates from BSA and AA was found to be about 102 M−1, which indicated low affinity of AA with BSA. For the BSA/AA films, it was also noted that the AA adsorption process and surface morphological structures depended on AA concentration. By changing the contact time between the AA and BSA, a hypochromism was revealed, which was associated to decrease of accessibility of solvent to tryptophan due to formation of aggregates. Furthermore, different morphological structures of aggregates were observed, which were attributed to the diffusion-limited aggregation. Since most of studies of interactions of drugs and proteins are performed in solution, the analysis of these processes by using films can be very valuable because this kind of system is able to employ several techniques of investigation in solid state.