27 research outputs found
Variability of Complement Response toward Preclinical and Clinical Nanocarriers in the General Population
Opsonization (coating) of nanoparticles
with complement C3 component
is an important mechanism that triggers immune clearance and downstream
anaphylactic and proinflammatory responses. The variability of complement
C3 binding to nanoparticles in the general population has not been
studied. We examined complement C3 binding to dextran superparamagnetic
iron oxide nanoparticles (superparamagnetic iron oxide nanoworms,
SPIO NWs, 58 and 110 nm) and clinically approved nanoparticles (carboxymethyl
dextran iron oxide ferumoxytol (Feraheme, 28 nm), highly PEGylated
liposomal doxorubicin (LipoDox, 88 nm), and minimally PEGylated liposomal
irinotecan (Onivyde, 120 nm)) in sera from healthy human individuals.
SPIO NWs had the highest variation in C3 binding (<i>n</i> = 47) between subjects, with a 15–30 fold range in levels
of C3. LipoDox (<i>n</i> = 12) and Feraheme (<i>n</i> = 18) had the lowest levels of variation between subjects (an approximately
1.5-fold range), whereas Onivyde (<i>n</i> = 18) had intermediate
between-subject variation (2-fold range). There was no statistical
difference between males and females and no correlation with age.
There was a significant correlation in complement response between
small and large SPIO NWs, which are similar structurally and chemically,
but the correlations between SPIO NWs and other types of nanoparticles,
and between LipoDox and Onivyde, were not significant. The calculated
average number of C3 molecules bound per nanoparticle correlated with
the hydrodynamic diameter but was decreased in LipoDox, likely due
to the PEG coating. The conclusions of this study are (1) all nanoparticles
show variability of C3 opsonization in the general population; (2)
an individual’s response toward one nanoparticle cannot be
reliably predicted based on another nanoparticle; and (3) the average
number of C3 molecules per nanoparticle depends on size and surface
coating. These results provide new strategies to improve nanomedicine
safety
Different Effect of Hydrogelation on Antifouling and Circulation Properties of Dextran–Iron Oxide Nanoparticles
Premature recognition and clearance of nanoparticulate
imaging
and therapeutic agents by macrophages in the tissues can dramatically
reduce both the nanoparticle half-life and delivery to the diseased
tissue. Grafting nanoparticles with hydrogels prevents nanoparticulate
recognition by liver and spleen macrophages and greatly prolongs circulation
times in vivo. Understanding the mechanisms by which hydrogels achieve
this “stealth” effect has implications for the design
of long-circulating nanoparticles. Thus, the role of plasma protein
absorption in the hydrogel effect is not yet understood. Short-circulating
dextran-coated iron oxide nanoparticles could be converted into stealth
hydrogel nanoparticles by cross-linking with 1-chloro-2,3-epoxypropane.
We show that hydrogelation did not affect the size, shape and zeta
potential, but completely prevented the recognition and clearance
by liver macrophages <i>in vivo</i>. Hydrogelation decreased
the number of hydroxyl groups on the nanoparticle surface and reduced
the binding of the anti-dextran antibody. At the same time, hydrogelation
did not reduce the absorption of cationic proteins on the nanoparticle
surface. Specifically, there was no effect on the binding of kininogen,
histidine-rich glycoprotein, and protamine sulfate to the anionic
nanoparticle surface. In addition, hydrogelation did not prevent activation
of plasma kallikrein on the metal oxide surface. These data suggest
that (a) a stealth hydrogel coating does not mask charge interactions
with iron oxide surface and (b) the total blockade of plasma protein
absorption is not required for maintaining iron oxide nanoparticles’
long-circulating stealth properties. These data illustrate a novel,
clinically promising property of long-circulating stealth nanoparticles
High-Relaxivity Superparamagnetic Iron Oxide Nanoworms with Decreased Immune Recognition and Long-Circulating Properties
One of the core issues of nanotechnology involves masking the foreignness of nanomaterials to enable <i>in vivo</i> longevity and long-term immune evasion. Dextran-coated superparamagnetic iron oxide nanoparticles are very effective magnetic resonance imaging (MRI) contrast agents, and strategies to prevent immune recognition are critical for their clinical translation. Here we prepared 20 kDa dextran-coated SPIO nanoworms (NWs) of 250 nm diameter and a high molar transverse relaxivity rate <i>R</i><sub>2</sub> (∼400 mM<sup>–1</sup> s<sup>–1</sup>) to study the effect of cross-linking-hydrogelation with 1-chloro-2,3-epoxypropane (epichlorohydrin) on the immune evasion both <i>in vitro</i> and <i>in vivo</i>. Cross-linking was performed in the presence of different concentrations of NaOH (0.5 to 10 N) and different temperatures (23 and 37 °C). Increasing NaOH concentration and temperature significantly decrease the binding of anti-dextran antibody and dextran-binding lectin conconavalin A to the NWs. The decrease in dextran immunoreactivity correlated with the decrease in opsonization by complement component 3 (C3) and with the decrease in the binding of the lectin pathway factor MASP-2 in mouse serum, suggesting that cross-linking blocks the lectin pathway of complement. The decrease in C3 opsonization correlated with the decrease in NW uptake by murine peritoneal macrophages. Optimized NWs demonstrated up to 10 h circulation half-life in mice and minimal uptake by the liver, while maintaining the large 250 nm size in the blood. We demonstrate that immune recognition of large iron oxide nanoparticles can be efficiently blocked by chemical cross-linking-hydrogelation, which is a promising strategy to improve safety and bioinertness of MRI contrast agents
Different Effect of Hydrogelation on Antifouling and Circulation Properties of Dextran–Iron Oxide Nanoparticles
Premature recognition and clearance of nanoparticulate
imaging
and therapeutic agents by macrophages in the tissues can dramatically
reduce both the nanoparticle half-life and delivery to the diseased
tissue. Grafting nanoparticles with hydrogels prevents nanoparticulate
recognition by liver and spleen macrophages and greatly prolongs circulation
times in vivo. Understanding the mechanisms by which hydrogels achieve
this “stealth” effect has implications for the design
of long-circulating nanoparticles. Thus, the role of plasma protein
absorption in the hydrogel effect is not yet understood. Short-circulating
dextran-coated iron oxide nanoparticles could be converted into stealth
hydrogel nanoparticles by cross-linking with 1-chloro-2,3-epoxypropane.
We show that hydrogelation did not affect the size, shape and zeta
potential, but completely prevented the recognition and clearance
by liver macrophages <i>in vivo</i>. Hydrogelation decreased
the number of hydroxyl groups on the nanoparticle surface and reduced
the binding of the anti-dextran antibody. At the same time, hydrogelation
did not reduce the absorption of cationic proteins on the nanoparticle
surface. Specifically, there was no effect on the binding of kininogen,
histidine-rich glycoprotein, and protamine sulfate to the anionic
nanoparticle surface. In addition, hydrogelation did not prevent activation
of plasma kallikrein on the metal oxide surface. These data suggest
that (a) a stealth hydrogel coating does not mask charge interactions
with iron oxide surface and (b) the total blockade of plasma protein
absorption is not required for maintaining iron oxide nanoparticles’
long-circulating stealth properties. These data illustrate a novel,
clinically promising property of long-circulating stealth nanoparticles
Different Effect of Hydrogelation on Antifouling and Circulation Properties of Dextran–Iron Oxide Nanoparticles
Premature recognition and clearance of nanoparticulate
imaging
and therapeutic agents by macrophages in the tissues can dramatically
reduce both the nanoparticle half-life and delivery to the diseased
tissue. Grafting nanoparticles with hydrogels prevents nanoparticulate
recognition by liver and spleen macrophages and greatly prolongs circulation
times in vivo. Understanding the mechanisms by which hydrogels achieve
this “stealth” effect has implications for the design
of long-circulating nanoparticles. Thus, the role of plasma protein
absorption in the hydrogel effect is not yet understood. Short-circulating
dextran-coated iron oxide nanoparticles could be converted into stealth
hydrogel nanoparticles by cross-linking with 1-chloro-2,3-epoxypropane.
We show that hydrogelation did not affect the size, shape and zeta
potential, but completely prevented the recognition and clearance
by liver macrophages <i>in vivo</i>. Hydrogelation decreased
the number of hydroxyl groups on the nanoparticle surface and reduced
the binding of the anti-dextran antibody. At the same time, hydrogelation
did not reduce the absorption of cationic proteins on the nanoparticle
surface. Specifically, there was no effect on the binding of kininogen,
histidine-rich glycoprotein, and protamine sulfate to the anionic
nanoparticle surface. In addition, hydrogelation did not prevent activation
of plasma kallikrein on the metal oxide surface. These data suggest
that (a) a stealth hydrogel coating does not mask charge interactions
with iron oxide surface and (b) the total blockade of plasma protein
absorption is not required for maintaining iron oxide nanoparticles’
long-circulating stealth properties. These data illustrate a novel,
clinically promising property of long-circulating stealth nanoparticles
Different Effect of Hydrogelation on Antifouling and Circulation Properties of Dextran–Iron Oxide Nanoparticles
Premature recognition and clearance of nanoparticulate
imaging
and therapeutic agents by macrophages in the tissues can dramatically
reduce both the nanoparticle half-life and delivery to the diseased
tissue. Grafting nanoparticles with hydrogels prevents nanoparticulate
recognition by liver and spleen macrophages and greatly prolongs circulation
times in vivo. Understanding the mechanisms by which hydrogels achieve
this “stealth” effect has implications for the design
of long-circulating nanoparticles. Thus, the role of plasma protein
absorption in the hydrogel effect is not yet understood. Short-circulating
dextran-coated iron oxide nanoparticles could be converted into stealth
hydrogel nanoparticles by cross-linking with 1-chloro-2,3-epoxypropane.
We show that hydrogelation did not affect the size, shape and zeta
potential, but completely prevented the recognition and clearance
by liver macrophages <i>in vivo</i>. Hydrogelation decreased
the number of hydroxyl groups on the nanoparticle surface and reduced
the binding of the anti-dextran antibody. At the same time, hydrogelation
did not reduce the absorption of cationic proteins on the nanoparticle
surface. Specifically, there was no effect on the binding of kininogen,
histidine-rich glycoprotein, and protamine sulfate to the anionic
nanoparticle surface. In addition, hydrogelation did not prevent activation
of plasma kallikrein on the metal oxide surface. These data suggest
that (a) a stealth hydrogel coating does not mask charge interactions
with iron oxide surface and (b) the total blockade of plasma protein
absorption is not required for maintaining iron oxide nanoparticles’
long-circulating stealth properties. These data illustrate a novel,
clinically promising property of long-circulating stealth nanoparticles
Dual-Porosity Hollow Nanoparticles for the Immunoprotection and Delivery of Nonhuman Enzymes
Although enzymes of nonhuman origin
have been studied for a variety
of therapeutic and diagnostic applications, their use has been limited
by the immune responses generated against them. The described dual-porosity
hollow nanoparticle platform obviates immune attack on nonhuman enzymes
paving the way to in vivo applications including enzyme-prodrug therapies
and enzymatic depletion of tumor nutrients. This platform is manufactured
with a versatile, scalable, and robust fabrication method. It efficiently
encapsulates macromolecular cargos filled through mesopores into a
hollow interior, shielding them from antibodies and proteases once
the mesopores are sealed with nanoporous material. The nanoporous
shell allows small molecule diffusion allowing interaction with the
large macromolecular payload in the hollow center. The approach has
been validated in vivo using l-asparaginase to achieve l-asparagine depletion in the presence of neutralizing antibodies
Isolation of Rare Tumor Cells from Blood Cells with Buoyant Immuno-Microbubbles
<div><p>Circulating tumor cells (CTCs) are exfoliated at various stages of cancer, and could provide invaluable information for the diagnosis and prognosis of cancers. There is an urgent need for the development of cost-efficient and scalable technologies for rare CTC enrichment from blood. Here we report a novel method for isolation of rare tumor cells from excess of blood cells using gas-filled buoyant immuno-microbubbles (MBs). MBs were prepared by emulsification of perfluorocarbon gas in phospholipids and decorated with anti-epithelial cell adhesion molecule (EpCAM) antibody. EpCAM-targeted MBs efficiently (85%) and rapidly (within 15 minutes) bound to various epithelial tumor cells suspended in cell medium. EpCAM-targeted MBs efficiently (88%) isolated frequent tumor cells that were spiked at 100,000 cells/ml into plasma-depleted blood. Anti-EpCAM MBs efficiently (>77%) isolated rare mouse breast 4T1, human prostate PC-3 and pancreatic cancer BxPC-3 cells spiked into 1, 3 and 7 ml (respectively) of plasma-depleted blood. Using EpCAM targeted MBs CTCs from metastatic cancer patients were isolated, suggesting that this technique could be developed into a valuable clinical tool for isolation, enumeration and analysis of rare cells.</p> </div
Tumor cell lines tested for anti-EpCAM MB binding.
<p>Tumor cell lines tested for anti-EpCAM MB binding.</p
Isolation of tumor cells with MBs and magnetic beads.
<p>Tumor cells were spiked into 1 ml of plasma-depleted mouse blood (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058017#s2" target="_blank">Methods</a>). Mouse EpCAM-targeted MBs and beads were added at 1×10<sup>7</sup> MB/ml. Following gentle mixing for 15 minutes, MB layer was separated from blood cells by centrifugation at 100 g for 2 minutes. Magnetic beads were separated with a neodymium magnet. <b><i>A</i></b>, Collection of the floating MB layer on top depends on the downstream analysis (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058017#s2" target="_blank">Methods</a>); <b><i>B</i></b>, After the isolation of MBs and beads, the cells were placed on a hemocytometer grid (MBs were destroyed for 1 second with gentle sonication) and the GFP-positive cells were counted at low magnification (40×). MBs and beads showed similar numbers of GFP+ cells in the isolated (enriched) fraction and near absence of GFP+ cells in the blood cell (depleted) fractions. For size reference, red outline shows the major 5×5 square of the hemocytometer; <b><i>C</i></b>, Quantification of isolation efficiency of GFP-4T1 cells. <b><i>D</i></b>, Quantification of tumor cell depletion from blood cells with flow cytometry. One ml of blood cells was spiked with non-labeled 4T1 cells at 1×10<sup>6</sup> cells/ml. Remaining blood cell fraction and the isolated MB fraction were analyzed for tumor cells after CD45 (leukocyte) and EpCAM staining (as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058017#s2" target="_blank">Methods</a>). Red blood cells were lysed and gated out (left image, FSC/SSC plot). MBs efficiently depleted 4T1 cells, and enriched them with 95.4% purity. A representative experiment out of two is shown.</p