| Attractive interactions between proteins and polyethylene glycol (PEG) give rise to ternary adsorption within PEG brushes. Experimental evidence suggests two ternary adsorption modes: (i) Weak, due to non-specific weak attraction between PEG monomers and the surface of the protein, exemplified by serum albumin; (ii) Strong, due to strong binding of PEG segments to specific protein sites, occurring for PEG antibodies, can involve terminal adsorption of free chain ends or backbone adsorption due to binding to ''interior'' chain segments. Ternary adsorption affects the capacity of brushes to repress protein adsorption. The strong adsorption of antibodies can trigger immune response affecting the biocompatibility of the surface. Theoretical adsorption isotherms and protein concentration profiles of the three cases are compared for ''parabolic'' brushes allowing for the grafting density, 1/Σ and polymerization degree of the PEG chains, N, as well as the volume and surface area of the proteins. The amount of adsorbed protein per unit area, $\Gamma,$ exhibits a mode specific maximum in all three cases. For backbone and weak adsorption Γ~N while for terminal adsorption $Γ~N0. In every case, the concentration profile of adsorbed proteins, ctern(z), exhibits a maximum at zmax>0 that shifts outwards as Σ decreases; zmax=0 occurs only for weak and backbone adsorption at a high Σ value.
for LaTeX users @article{AHalperin2009-25,
author = {A. Halperin and M. Kr\"oger},
title = {Ternary protein adsorption onto brushes: Strong versus weak},
journal = {Langmuir},
volume = {25},
pages = {11621-11634},
year = {2009}
}
\bibitem{AHalperin2009-25} A. Halperin, M. Kr\"oger,
Ternary protein adsorption onto brushes: Strong versus weak,
Langmuir {\bf 25} (2009) 11621-11634.AHalperin2009-25
A. Halperin, M. Kr\"oger
Ternary protein adsorption onto brushes: Strong versus weak
Langmuir,25,2009,11621-11634 |
mk@mat.ethz.ch
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