Biomedical Engineering Reference
In-Depth Information
the entropy of adsorbed proteins. It should be noted that the adsorption of proteins
by this entropy-driven mechanism usually does not change the conformation of the
protein [
7
]. The change in the conformation of human adult hemoglobin has been
reported for bare CdS nanoparticles [
7
]. The sulfur atoms of cysteine residues are
the main linker for attachment of hemoglobin on the surface of CdS nanoparticle
which is accompanied by around 10 % decrease in the alpha-helix structure content.
Lundqvist et al. [
8
] incubated nanoparticles with plasma and then transferred
them with their corresponding hard protein corona into cytosolic fluid. Following a
second incubation, the hard protein corona is determined and compared to that of
incubation in each fluid separately (plasma and cytosolic fluid). Three different
nanoparticles (9 nm silica, 50 nm polystyrene, and 50 nm carboxyl-modified
polystyrene particles) were incubated in either human plasma, cytosolic fluid, or
in plasma followed by cytosolic fluid, and then the bound proteins (hard corona)
were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis
(SDS-PAGE). The results confirm that significant evolution of the corona occurs
in the second biological solution but that the final corona contains a “fingerprint” of
its history. They concluded that this could be evolved to map the transport pathways
utilized by NPs and eventually to predict fate and behavior of nanoparticles in
the body.
Karmali and Simberg [
9
] have reviewed the identification of plasma proteins
adhering to different nanoparticles which is summarized below. It is well known
that the surface chemistry plays the dominant role in the recognition:
• Apolipoproteins are the main type of proteins which adsorb on liposomes and
polymeric nanoparticles, but not inorganic nanoparticles. The exchange of
apolipoprotein between lipoproteins and nanoparticles that have hydrophobic
domains was suggested to be the main mechanism of adsorption. Using model
polymer particles with decreasing hydrophobicity, Gessner et al. [
10
]
demonstrated that ApoA-I, ApoA-IV, ApoC-III, and ApoJ gradually disappear
with decreasing hydrophobicity of the nanoparticle.
• The most abundant proteins, albumin and fibrinogen, were found on many types
of nanoparticle.
• Cationic lipoplexes and polyplexes show strong albumin binding, probably
because albumin is a negatively charged protein. Albumin also shows affinity
for hydrophobic surfaces and polyanions.
• Transferrin, haptoglobin, fetuin A (alpha-2-HS-glycoprotein), kininogen,
histidine-rich glycoprotein, and contact (intrinsic) clotting pathway factors can
be attracted by polymer nanoparticles and nanoparticles with hydrophobic
surface component or hydrophilic inorganic nanoparticles. Most of these
proteins are able to adhere to the anionic and metal surfaces.
• Presence of hydroxyl groups (e.g., dextran and sugars) promotes the binding of
C3 complement through its thioester group. Mannose-binding lectins (MBLs)
were shown to bind to sugar moieties of dextran-coated nanoparticles.
• Specific binding of serum mannose-binding protein (MBP) to phosphatidy-
linositol (PI) liposomes has been demonstrated.
• Dextran-coated particles appear to be recognized by antibodies.
