Anomalous thermal denaturing of proteins adsorbed to nanoparticles
Department of Physics, Department of Optometry, and Guelph-Waterloo Physics Institute, University of Waterloo, 200 University Ave. W., N2L 3G1, Waterloo, Ontario, Canada
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Accepted: 8 September 2006
Published online: 16 October 2006
We have used localized surface plasmon resonance (LSPR) to monitor the structural changes that accompany thermal denaturing of bovine serum albumin (BSA) adsorbed onto gold nanospheres of size 5nm-60nm. The effect of the protein on the LSPR was monitored by visible extinction spectroscopy. The position of the resonance is affected by the conformation of the adsorbed protein layer, and as such can be used as a very sensitive probe of thermal denaturing that is specific to the adsorbed protein. The results are compared to detailed calculations and show that full calculations can lead to significant increases in knowledge where gold nanospheres are used as biosensors. Thermal denaturing on spheres with diameter > 20 nm show strong similarity to bulk calorimetric studies of BSA in solution. BSA adsorbed on nanospheres with d ⩽ 15nm shows a qualitative difference in behavior, suggesting a sensitivity of denaturing characteristics on local surface curvature. This may have important implications for other protein-nanoparticle interactions.
PACS: 78.67.Bf Nanocrystals and nanoparticles – / 87.80.-y Biological techniques and instrumentation; biomedical engineering – / 87.83.+a Biomedical applications of nanotechnology –
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2006