Shape dependent protein induced stabilization of gold nanoparticles:
from protein corona perspective.
Abstract
Gold nanoparticles (GNPs) are promising materials for many
bioapplications. However, upon contacting with biological media, GNPs
undergo changes. The interaction with proteins results in the so-called
protein corona (PC) around GNPs, leading to the new bioidentity and
optical properties. Understanding the mechanisms of PC formation and its
functions can help us to utilise its benefits and avoid its drawbacks.
To date, most of the previous works aimed to understand the mechanisms
governing PC formation and focused on the spherical nanoparticles
although non-spherical nanoparticles are designed for a wide range of
applications in biosensing. In this work, we investigated the
differences in PC formation on spherical and anisotropic GNPs (nanostars
in particular) from the joint experimental (extinction spectroscopy,
zeta potential and surface enhanced Raman scattering [SERS]) and
computational methods (the finite element method and molecular dynamics
[MD] simulations). We discovered that protein does not fully cover
the surface of anisotropic nanoparticles, leaving SERS hot-spots at the
tips and high curvature edges “available” for analyte binding (no SERS
signal after pre-incubation with protein) while providing
protein-induced stabilization (indicated by extinction spectroscopy) of
the GNPs by providing a protein layer around the particle’s core. The
findings are confirmed from our MD simulations, the adsorption energy
significantly decreases with the increased radius of curvature, so that
tips (adsorption energy: 2762.334 kJ/mol) would be the least
preferential binding site compared to core (adsorption energy: 11819.263
kJ/mol). These observations will help the development of new
nanostructures with improved sensing and targeting ability.