Sensitive Analysis of Protein Adsorption to Colloidal Gold by Differential Centrifugal Sedimentation.

Anal Chem

Surface Science Research Centre, Department of Chemistry, University of Liverpool, Abercromby Square, Liverpool L69 3BX, U.K.

Published: June 2017


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Article Abstract

It is demonstrated that the adsorption of bovine serum albumin (BSA) to aqueous gold colloids can be quantified with molecular resolution by differential centrifugal sedimentation (DCS). This method separates colloidal particles of comparable density by mass. When proteins adsorb to the nanoparticles, both their mass and their effective density change, which strongly affects the sedimentation time. A straightforward analysis allows quantification of the adsorbed layer. Most importantly, unlike many other methods, DCS can be used to detect chemisorbed proteins ("hard corona") as well as physisorbed proteins ("soft corona"). The results for BSA on gold colloid nanoparticles can be modeled in terms of Langmuir-type adsorption isotherms (Hill model). The effects of surface modification with small thiol-PEG ligands on protein adsorption are also demonstrated.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5480231PMC
http://dx.doi.org/10.1021/acs.analchem.7b01229DOI Listing

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