INVESTIGADORES
AVENA Marcelo Javier
artículos
Título:
Ellipsometric study of bovine serum albumin adsorbed onto Ti/TiO2 electrodes
Autor/es:
C.E. GIACOMELLI; M.J. ESPLANDIÚ; P.I. ORTIZ; M.J. AVENA; C.P. DE PAULI.
Revista:
JOURNAL OF COLLOID AND INTERFACE SCIENCE
Editorial:
ACADEMIC PRESS INC ELSEVIER SCIENCE
Referencias:
Lugar: Amsterdam; Año: 1999 vol. 218 p. 404 - 411
ISSN:
0021-9797
Resumen:
The adsorption of bovine serum albumin (BSA) onto relatively
hydrophobic TiO 2 surfaces was studied by ellipsometry as a func-
tion of pH and BSA concentration. Titanium oxide layers were
electrochemically grown on Ti disc electrodes. When fast attach-
ment of BSA onto TiO 2 takes place, the adsorption can be consid-
ered as occurring in two different steps. The first step is fast and
is the result of the direct adsorption of the protein molecules that
attach to the surface without changing their conformation. The
second process is slow and lasts for several hours. In this process,
the adsorbed amount remains constant, whereas the thickness of
the layer increases and its refractive index decreases with time.
The changes in this second step are due mainly to rearrangements
in the adsorbed layer produced by variations in the conformation
and structure of the adsorbed molecules. The main conformational
changes take place in the direction normal to the surface because
lateral molecule?molecule interactions impede significant lateral
expansion. Adsorption from BSA solutions of low concentration
does not appear to lead to significant reconformation of the pro-
tein layer. Comparison with adsorption on powdered TiO 2 indi-
cates that the adsorbed amount and the effective area occupied by
an adsorbed BSA molecule can remain about constant even when
strong surface reconformation takes place.