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Physicochemical Characteristics of Protein–NP Bioconjugates: The Role of Particle Curvature and Solution Conditions on Human Serum Albumin Conformation and Fibrillogenesis Inhibition
journal contribution
posted on 2012-06-19, 00:00 authored by Sonia Goy-López, Josué Juárez, Manuel Alatorre-Meda, Eudald Casals, Victor F. Puntes, Pablo Taboada, Victor MosqueraGold nanoparticles (Au NPs) from 5 to 100 nm in size
synthesized
with HAuCl4 and sodium citrate were complexed with the
plasma protein human serum albumin (HSA). Size, surface charge, and
surface plasmon bands of the Au NPs are largely modified by the formation
of a protein corona via electrostatic interactions and hydrogen bonding
as revealed by thermodynamic data. Negative values of the entropy
of binding suggested a restriction in the biomolecule mobility upon
adsorption. The structure of the adsorbed protein molecules is slightly
affected by the interaction with the metal surface, but this effect
is enhanced as the NP curvature decreases. Also, it is observed that
the protein molecules adsorbed onto the NP surface are more resistant
to complete thermal denaturation than free protein ones as deduced
from the increases in the melting temperature of the adsorbed protein.
Differences in the conformations of the adsorbed protein molecules
onto small (<40 nm) and large NPs were observed on the basis of
ζ-potential data and FTIR spectroscopy, also suggesting a better
resistance of adsorbed protein molecules to thermal denaturing conditions.
We think this enhanced protein stability is responsible for a reduced
formation of HSA amyloid-like fibrils in the presence of small Au
NPs under HSA fibrillation conditions.