In Situ Measurement of
Bovine Serum Albumin Interaction
with Gold Nanospheres
- Publication date
- Publisher
Abstract
We present in situ observations of adsorption of bovine
serum albumin
(BSA) on citrate-stabilized gold nanospheres. We implemented scattering
correlation spectroscopy as a tool to quantify changes in the nanoparticle
Brownian motion resulting from BSA adsorption onto the nanoparticle
surface. Protein binding was observed as an increase in the nanoparticle
hydrodynamic radius. Our results
indicate the formation of a protein monolayer at similar albumin concentrations
as those found in human blood. Additionally, by monitoring the frequency
and intensity of individual scattering events caused by single gold
nanoparticles passing the observation volume, we found that BSA did
not induce colloidal aggregation, a relevant result from the toxicological
viewpoint. Moreover, to elucidate the thermodynamics of the gold nanoparticle–BSA
association, we measured an adsorption isotherm which was best described
by an anticooperative binding model. The number of binding sites based
on this model was consistent with a BSA monolayer in its native state.
In contrast, experiments using poly(ethylene glycol)-capped gold nanoparticles
revealed no evidence for adsorption of BSA