J. R. Hunter, R. Z. Guzman,
R. G. Carbonell, and P. K. Kilpatrick
Adsorption of Proteins at
Gas-Liquid Interfaces
Proteins adsorb at
gas-liquid interfaces in multiple layers, as evidenced by the radiotracer and ellipsometric experiments of Graham and Phillips (1). We
have developed a kinetic model of protein adsorption isotherms and adsorption
kinetics which incorporates multilayer adsorption, a dependence of activation
energy of adsorption and desorption on surface concentration, and mass transfer effects in the bulk
solution. The model successfully correlates experimental data of adsorption
isotherms and adsorption rates for the three proteins b-casein,
bovine serum albumin, and lysozyme (EC 3.2.1.22).
We have also built
an experimental apparatus to measure the energy spectrum of b-particles emitted
from 14C-labelled proteins and surfactants. Our technique for data
analysis takes advantage of the qualitafive
difference in the energy spectra of b-particles emitted from bulk solute and of
those emitted from surface-adsorbed species. In future experiments, the
technique will be employed to determine adsorption isotherms and kinetics of 14C-labelled
proteins in the presence and absence of affinity ligand-labelled
surfactants. The initial adsorption experiments will be performed on radiolabelled avidin in the
presence and absence of biotnylated mono-hexadecyl octaethylene glycol.
(1) Graham, D. E.,
and Phillips, M. C. (1979)
J. Colloid Interface Sci,
70, 403-414
Department of
Chemical Engineering