Size-dependent denaturing kinetics of bovine serum albumin adsorbed onto gold nanospheres
Department of Physics and Astronomy, Department of Optometry, and Guelph-Waterloo Physics Institute, University of Waterloo, 200 University Ave. W., Waterloo, Ontario, N2L 3G1, Canada
* e-mail: email@example.com
Revised: 25 April 2008
Published online: 8 July 2008
We have used localized surface plasmon resonance (LSPR) to monitor the kinetics of thermal denaturing of bovine serum albumin (BSA) adsorbed onto gold nanospheres of size 5 nm-100 nm. The effect of the protein on the LSPR was monitored by visible extinction spectroscopy. The wavelength of the peak extinction (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 (as opposed to free) protein. The time dependence of the denaturing is measured in the temperature range 60 °C–70 °C, and the lifetimes are used to calculate an activation barrier for thermal denaturing. The results show that thermally activated denaturing of proteins adsorbed onto nanoparticles has a nanoparticle-size-dependent activation barrier, and this barrier increases for decreasing particle size. This may have important implications for other protein-nanoparticle interactions.
PACS: 87.64.-t Spectroscopic and microscopic techniques in biophysics and medical physics – / 78.67.Bf Nanocrystals and nanoparticles – / 87.15.hm Folding dynamics – / 87.15.hp Conformational changes –
© Springer, 2008