Environmental Engineering Reference
In-Depth Information
sizes of each (50 and 100 nm) to study the effect of surface properties and size on
the detailed protein coronas [
60
]. Particles were incubated with plasma for 1 h
followed by centrifugation to form pellets and extensive washing to remove all of
the unbound proteins. The pellet size increased with increasing plasma concentra-
tion with subsequent decrease of the pellet size for all particles except the 100-nm
amine-modified particles. The different behaviour for the amine-modified 100-nm
particles compared with the other ones could be due to aggregation of the amine-
modified 100-nm particles. Bound proteins were eluted from the particles and
separated by 1D-PAGE. Selected bands were excised and the proteins were trypsin
digested before detection by mass spectrometry.
For the
particles, the major part of the “hard” corona consisted of
fibrinogen, IgG, albumin and inter-alpha-trypsin inhibitor heavy chain [
61
]. The
coronas around two different sized neutral polystyrene particles was very similar
(80 % homology) suggesting that the molecular (e.g. hydrophobic) properties are
more important than size for neutral nanoparticles. The homology between the
coronas for the carboxyl-modified and amine-modified particles was only 50 %.
Although many of the major highly abundant proteins in the corona are independent
of size and surface charge, a whole range of proteins (many of them having quite
distinct biological roles relevant to nanomedicine and nanosafety) form part of the
corona. The nature of the proteins in the corona is determined by the chemical
properties of the nanoparticle [
62
]. However, even for a fixed material type, the size
of the particle and its surface modification are able to entirely change the nature of
the biologically active proteins in the corona, and thereby possibly also the biolog-
ical impacts.
neutral
'
'
15.2.6 Hydrophobicity and Shape
The adsorption of proteins on the particles surface after
i.v
. administration depends
on their surface characteristics and is regarded as key factor for the in vivo organ
distribution. Surface hydrophobicity highly influences the plasma protein adsorp-
tion patterns [
63
]. Latex particles with decreasing surface hydrophobicity were
synthesised as model colloidal carriers to study the effect of hydrophobicity on
plasma protein adsorption patterns. Surface hydrophobicity was determined by the
adsorption of a hydrophobic dye Rose Bengal and the adsorption pattern was
analysed employing 2-DE [
64
]. Acrolein particles with lowest hydrophobicity
showed minimum protein adsorption while Styrene with highest hydrophobicity
showed maximal adsorption. The major proteins adsorbed on the particles of each
type were Fibrinogen (35 % of the overall pattern) and IgG (35.7 % of the overall
pattern). Adsorption of Fibrinogen and the Apolipoproteins was affected by dimin-
ished surface hydrophobicity. The adsorption of the large proteins like Albumin,
Fibrinogen and IgG decreased, but also the Apolipoproteins A-IV and J (MW 45
and 52 kDa) were strongly diminished with decreasing hydrophobicity of the
