posted on 2023-01-10, 23:29authored byKira M. Fahy, Madeline K. Eiken, Karl V. Baumgartner, Kaitlyn Q. Leung, Sarah E. Anderson, Erik Berggren, Evangelia Bouzos, Lauren R. Schmitt, Prashanth Asuri, Korin E. Wheeler
Engineered nanomaterials
(ENMs) are synthesized with a diversity
of surface chemistries that mediate biochemical interactions and physiological
response to the particles. In this work, silver engineered nanomaterials
(AgENMs) are used to evaluate the role of surface charge in protein
interactions and cellular cytotoxicity. The most abundant protein
in blood, human serum albumin (HSA), was interacted with 40 nm AgENMs
with a range of surface-charged coatings: positively charged branched
polyethyleneimine (bPEI), negatively charged citrate (CIT), and circumneutral
poly(ethylene glycol) (PEG). HSA adsorption to AgENMs was monitored
by UV–vis spectroscopy and dynamic light scattering, while
changes to the protein structure were evaluated with circular dichroism
spectroscopy. Binding affinity for citrate-coated AgENMs and HSA is
largest among the three AgENM coatings; yet, HSA lost the most secondary
structure upon interaction with bPEI-coated AgENMs compared to the
other two coatings. HSA increased AgENM oxidative dissolution across
all particle types, with the greatest dissolution for citrate-coated
AgENMs. Results indicate that surface coating is an important consideration
in transformation of both the particle and protein upon interaction.
To connect results to cellular outcomes, we also performed cytotoxicity
experiments with HepG2 cells across all three AgENM types with and
without HSA. Results show that bPEI-coated AgENMs cause the greatest
loss of cell viability, both with and without inclusion of HSA with
the AgENMs. Thus, surface coatings on AgENMs alter both biophysical
interactions with proteins and particle cytotoxicity. Within this
study set, positively charged bPEI-coated AgENMs cause the greatest
disruption to HSA structure and cell viability.