Coverage-Dependent Morphology of PEGylated Lysozyme Layers Adsorbed on Silica

Published

January 4, 2012

Author(s)

Sheetal S. Pai, Frank Heinrich, Adam L. Canady, Todd M. Przybycien, Robert D. Tilton

Abstract

Neutron reflection was used to characterize the adsorbed layer structure for lysozyme conjugated at the N-terminus with a single perdeuterated methoxy poly(ethylene glycol) chain at the silica/water interface. Adsorbed layers were produced with two different surface concentrations corresponding to opposite sides of a pronounced transition in the adsorption isotherm. The transition was previously ascribed, on the basis of less direct characterization by normal force measurements, to an orientation change of the PEGylated molecule on the surface in response to lateral repulsions (S.M. Daly, T.M. Przybycien, R.D. Tilton, Langmuir 21 (2005) 1328-1337). Neutron reflectivity was measured for both surface concentrations using three different sets of neutron scattering length density contrast conditions, and models for the distribution of PEG and lysozyme content in the layers were obtained by simultaneous regression of all contrast condition data sets. This analysis indicated that the surface proximal volume is occupied almost equally by PEG and lysozyme at the low surface concentration, while at the higher surface concentration PEG is preferentially shifted away from the surface, with all lysozyme remaining in the surface proximal region. The distal regions of the high surface concentration layer contain only PEG.

Citation

Journal of Colloid and Interface Science

Volume

370

Pub Type

Journals

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Keywords

neutron reflectometry, PEG, lysozyme

Citation

Pai, S. , Heinrich, F. , Canady, A. , Przybycien, T. and Tilton, R. (2012), Coverage-Dependent Morphology of PEGylated Lysozyme Layers Adsorbed on Silica, Journal of Colloid and Interface Science, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=909480 (Accessed April 29, 2024)