10.1021/la402920f.s001
Stefano
P. Boulos
Stefano
P.
Boulos
Tyler A. Davis
Tyler A.
Davis
Jie An Yang
Jie An
Yang
Samuel E. Lohse
Samuel E.
Lohse
Alaaldin M. Alkilany
Alaaldin M.
Alkilany
Lisa A. Holland
Lisa A.
Holland
Catherine J. Murphy
Catherine J.
Murphy
Nanoparticle–Protein Interactions: A Thermodynamic
and Kinetic Study of the Adsorption of Bovine Serum Albumin to Gold
Nanoparticle Surfaces
American Chemical Society
2013
nanoparticle
Bovine Serum Albumin
method
surface charge
equilibrium binding constants
ACE
affinity capillary electrophoresis
adsorption process
fluorescence quenching analysis
NP
fluorescence quenching titration
BSA
Gold Nanoparticle SurfacesInvestigating
determination
GNP
material compatibility issues
protein adsorption
2013-12-03 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Nanoparticle_Protein_Interactions_A_Thermodynamic_and_Kinetic_Study_of_the_Adsorption_of_Bovine_Serum_Albumin_to_Gold_Nanoparticle_Surfaces/2348089
Investigating the adsorption process
of proteins on nanoparticle
surfaces is essential to understand how to control the biological
interactions of functionalized nanoparticles. In this work, a library
of spherical and rod-shaped gold nanoparticles (GNPs) was used to
evaluate the process of protein adsorption to their surfaces. The
binding of a model protein (bovine serum albumin, BSA) to GNPs as
a function of particle shape, size, and surface charge was investigated.
Two independent comparative analytical methods were used to evaluate
the adsorption process: steady-state fluorescence quenching titration
and affinity capillary electrophoresis (ACE). Although under favorable
electrostatic conditions kinetic analysis showed a faster adsorption
of BSA to the surface of cationic GNPs, equilibrium binding constant
determinations indicated that BSA has a comparable binding affinity
to all of the GNPs tested, regardless of surface charge. BSA was even
found to adsorb strongly to GNPs with a pegylated/neutral surface.
However, these fluorescence titrations suffer from significant interference
from the strong light absorption of the GNPs. The BSA–GNP equilibrium
binding constants, as determined by the ACE method, were 10<sup>5</sup> times lower than values determined using spectroscopic titrations.
While both analytical methods could be suitable to determine the binding
constants for protein adsorption to NP surfaces, both methods have
limitations that complicate the determination of protein–GNP
binding constants. The optical properties of GNPs interfere with <i>K</i><sub>a</sub> determinations by static fluorescence quenching
analysis. ACE, in contrast, suffers from material compatibility issues,
as positively charged GNPs adhere to the walls of the capillary during
analysis. Researchers seeking to determine equilibrium binding constants
for protein–GNP interactions should therefore utilize as many
orthogonal techniques as possible to study a protein–GNP system.