Ultrasensitive probing of the protein resistance of PEG surfaces by secondary ion mass spectrometry

Citation

Kingshott, Peter; McArthur, Sally; Thissen, Helmut; Castner, David G.; & Griesser, Hans J. (2002). Ultrasensitive probing of the protein resistance of PEG surfaces by secondary ion mass spectrometry. Biomaterials, 23(24), 4775-4785.

Abstract

The highly sensitive surface analytical techniques X-ray photoelectron spectroscopy (XPS) and time-of-flight static secondary ion mass spectrometry (ToF-SIMS) were used to test the resistance of poly(ethylene glycol) (PEG) coatings towards adsorption of lysozyme (LYS) and fibronectin (FN). PEG coatings were prepared by grafting methoxy-terminated aldehyde-PEG (MW 5000 Da) onto two amino-functionalised surfaces with different amine group densities, generated by radio frequency glow discharge polymerisation of n-heptylamine and allylamine. Grafting was performed at the lower critical solution temperature to maximise the graft density of the PEG chains. XPS showed that the grafted density of PEG chains was slightly higher on the allylamine surface. XPS detected no adsorption of either protein on either PEG coating. ToF-SIMS analysis, on the other hand, found, in the positive ion spectra, minute but statistically significant signals assignable to amino acid fragment ions from both proteins adsorbed to the lower density PEG coating and from LYS but not FN on the higher density PEG coating. Negative ion spectra contained relatively more intense protein fragment ion signals for the lower density PEG coating but no changes assignable to adsorbed proteins on the higher density PEG coating. These results demonstrate the importance of utilising highly sensitive techniques to study protein adsorption on surfaces intended to be protein resistant, and that both positive and negative ion ToF-SIMS spectra should be acquired to probe for possible very low levels of protein adsorption.

Keyword(s)

Adsorption
Animals
Biocompatible Materials
Chickens
Electron Probe Microanalysis
Fibronectins
Humans
Mass Spectrometry
Muramidase
Polyethylene Glycols
Temperature

Reference Type

Journal Article

Secondary Title

Biomaterials

Author(s)

Kingshott, Peter
McArthur, Sally
Thissen, Helmut
Castner, David G.
Griesser, Hans J.

Year Published

2002

Volume Number

Issue Number

Pages

4775-4785