Neutralized Chimeric Avidin Binding at a Reference Biosensor Surface

We describe the development of a reference biosensor surface, based upon a binary mixture of oligo-ethylene glycol thiols, one of which has biotin at the terminus, adsorbed onto gold as self-assembled monolayers (SAMs). These surfaces were analyzed in detail by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) to establish the relationship between the thiol solution composition and the surface composition and structure. We report the use of argon cluster primary ions for the analysis of PEG-thiols, establishing that the different thiols are intimately mixed and that SIMS may be used to measure surface composition of thiol SAMs on gold with a detection limit better than 1% fractional coverage. The adsorption of neutralized chimeric avidin to these surfaces was measured simultaneously using ellipsometry and QCM-D. Comparison of the two measurements demonstrates the expected nonlinearity of the frequency response of the QCM but also reveals a strong variation in the dissipation signal that correlates with the surface density of biotin. These variations are most likely due to the difference in mechanical response of neutralized chimeric avidin bound by just one biotin moiety at low biotin density and two biotin moieties at high density. The transition between the two modes of binding occurs when the average spacing of biotin ligands approaches the diameter of the avidin molecule.

Steven, R. T.National Physical Laboratory (NPL) (author)
Green, F. M.National Physical Laboratory (NPL) (author)
Höök, Fredrik,1966Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)fredrikh (author)
Taskinen, B.Tampereen Yliopisto,University of Tampere (author)
Hytonen, V. P.Tampereen Yliopisto,University of Tampere (author)
Shard, A. G.National Physical Laboratory (NPL) (author)
National Physical Laboratory (NPL)Chalmers tekniska högskola (creator_code:org_t)

In:Langmuir: American Chemical Society (ACS)31:6, s. 1921-19301520-58270743-7463

By the author/editor: Ray, S.; Steven, R. T.; Green, F. M.; Höök, Fredrik, 1 ...; Taskinen, B.; Hytonen, V. P.; show more...; Shard, A. G.; show less...

About the subject

NATURAL SCIENCES: NATURAL SCIENCES; and Physical Science ...; and Condensed Matter ...

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