Biomedical Engineering Reference
In-Depth Information
2.4.6 Biological Environment
Maiorano et al. [
29
] studied the nano-biointeractions occurring between commonly
used cell culture media and differently sized citrate-coated gold nanoparticles (Au
NP) by different spectroscopic techniques (DLS, UV-visible, and PRLS). They
determined how media composition influences the formation of protein-NP
complexes that may affect the cellular response. They demonstrated that
protein-NP interactions are differently mediated by two widely used cellular
media (DMEM and Roswell Park Memorial Institute medium (RPMI)
supplemented with the protein source Fetal bovine serum (FBS)). These media
are exploited for most cell cultures and strongly vary in amino acid, glucose, and
salt composition. A range of spectroscopic, electrophoretic, and microscopic
techniques were applied in order to describe the biomolecular entities formed by
dispersing the different sized NP in the cellular culture media. They characterized
protein corona composition, exchanging kinetics of different protein classes, along
with the physical status of gold NP in terms of agglomeration/aggregation over
time. They observe that DMEM elicits the formation of a large time-dependent
protein corona and RPMI shows different dynamics with reduced protein coating.
Polyacrylamide gel electrophoresis and mass spectroscopy have revealed that the
average composition of protein corona does not reflect the relative abundance of
serum proteins. To evaluate the biological impact of the new bio-nanostructures,
several comparative viability assays onto two cell lines (HeLa (human epithelial
cervical cancer cell line) and U937 (human leukemic monocyte lymphoma cell
line)) were carried out in the DMEM and RPMI media, in the presence of 15 nm Au
NP. Au NP uptake and cellular distribution were addressed by applying a label-free
tracking method, based on two-photon confocal microscopy. They observed that
the dynamics of protein-NP interactions are differently mediated by the different
composition of cellular media. DLS, UV-vis absorption, and PRLS data, obtained
by in situ studies, revealed effects on the physical status of the NP mediated by
DMEM or RPMI. In particular, DMEM induced a more abundant and quite stable
protein corona on different sizes of Au NPs as compared to RPMI. These
observations were also confirmed by ex situ analyses, in which the strongly
adsorbed proteins onto metal surfaces were analyzed by SDS-PAGE and Mass
Spectrometry (MS). The different formation of proteins-NP complexes mediated
by liquid environment can impact on cellular response (Fig.
2.4
).
These results obtained showed that before cellular experiments, a detailed
understanding of the effects elicited by cell culture media on NP is crucial for
standardized nanotoxicology tests. Thereby, to evaluate NP dose-dependence tox-
icity in in vitro tests, all experimental parameters, comprising the choice of the
cellular medium, as well as the origin and preparation of serum, should be carefully
taken into account with the aim to design standardized protocols.
Monopoli et al. [
1
] employed differential centrifugal sedimentation and dynamic
light-scattering techniques and showed that by decreasing the concentration of
plasma, the thickness of hard protein corona around nanoparticles decreases.
