Hybrid Nanomaterials for Biomedical Imaging and Cancer ...
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Hybrid Nanomaterials for Biomedical Imaging and Cancer Therapy Wenbin Lin Department of Chemistry University of North Carolina Chapel Hill, NC 27599 [email protected]
Transcript of Hybrid Nanomaterials for Biomedical Imaging and Cancer ...
Hybrid Nanomaterials for Biomedical Imaging and Cancer
Therapy
Wenbin Lin
Department of ChemistryUniversity of North Carolina
Chapel Hill, NC [email protected]
Magnetic Resonance Imaging• Measures NMR signal of protons, mainly those of water• Different concentrations in different tissues lead to contrast in the image
• T1 weighted images show more intense signal where the longitudinal relaxation rate is fast (T1 is short)
Properties Needed for a Good Contrast Agent:• Large spin number
• Slow electron relaxation
• Site for water coordination, and the ability to undergo fast water exchange with the solvent
• Slow rotational diffusion
Pre-contrast
Post-contrast
Presenter
Presentation Notes
Magnetic resonance imaging is a very powerful imaging modality because of its high spatial resolution. However, MRI is very insensitive. As a result, a contrast enhancement agent is often needed to aid in disease diagnosis. Over the past couple of decades, the general principles for designing small-molecule MRI contrast agents are well-established. But it is important to point out that these small-molecule contrast agents are not powerful enough for target-specific MRI imaging. In fact, the relaxivity, which measures the ability of the contrast agents to relax water protons, is 5-6 orders of magnitude too small for target-imaging.
T1-weighted MRI Contrast Agents
• High spatial Resolution• No limit to penetration depth• High soft tissue contrast• Low sensitivity!
– Use of non-radiative contrast agents to increase MR signal intensity
• Free Gd3+ TOXIC!• Relaxivity (T1
-1 vs [Gd])• r1 ~ 4 mM-1s-1 (3 T)• 0.1 to 0.2 mmol kg-1
– 7 to 10 g / 70 kg human
Presenter
Presentation Notes
Commercially available t1 enhancing contrast agents typically come in the form of metal chelate complexes much like the ones shown here. They are administered in this safe and stable form to prevent toxic gadolinium ions from accumulating in the bone. There are many characteristics of effective t1 enhancing contrast agents… For example… diamide
Why Nanoparticulate Contrast Agents?
Artemov, D. J. Cellular Biochem. 2003, 90, 518.
Sensitivity: Enhanced r1 due to increased rotational correlation time – increases S/N ratio– decreases dose
High Metal Payloads: Large particle r1
– increase in potential applications (e.g. targeting)
Pharmacokinetics: Surface modification for longer circulation times – increases S/N– avoid RES and take advantage of EPR
Target Specificity: taking advantage of over-expressed biological markers
Targeted MR Contrast
Artemov, D. J. Cellular Biochem. 2003, 90, 518.
Mulder et al. Bioconjugate Chem. 2004, 15, 799-806
Presenter
Presentation Notes
One way to bridge the gap in MR relaxivity is to use nanotechnology to increase the payloads of paramagnetic metal centers in the nanoparticles. If one can increase the relaxivity by 5-6 orders of magnitude, one would be able to target the NPs with affinity molecules. In so doing, we might be able to achieve target-specific imaging. Two major systems have been investigated: iron oxide nanoparticles and Gd-incorporated liposomes. While both types of nanoparticles have shown great promises, new strategies are clearly needed in order to develop more effective nanoparticle platforms for efficient target-specific MR imaging of cancers.
Fluorescently-Labeled MR-Enhancing Silica Nanoparticles
=
Si-DTTA = trimethoxysilylpropyl diethylenetriaminetetraacetate
W = 15: 37 nm, ~10000 Gd/particle
R1 = ~4×105 mM-1●s-1
R2 = ~1.2×106 mM-1●s-1
02468
101214161820
0 0.05 0.1 0.15 0.2[Gd] (mM)
1 / T
(1/s
)
R2: 60.0 mM-1·s-1
R1: 19.7 mM-1·s-1
Presenter
Presentation Notes
In the second strategy, we synthesized nanoparticles that contain fluoresecnt cores and Gd chelate coatings. These chelates are very stable and will not leach out free Gd.
Monocyte Cell Labeling: LCFS and MRI Studies
40X
0
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80
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0 0.0123 0.123 1.23 12.3 123[Nanoparticle] (ug/5000 cells)
% V
iabi
lity
100 101 102 103 1040
500
R2
0 2560
256
SS
FS
W.J. Rieter, J.S. Kim, K.M. L. Taylor, H. An, W. Lin, T. Tarrant, W. Lin, Angew. Chem. 2007, 46, 3680-3682.
• Efficient nanoparticle uptake by monocyte cells (>98 %)
• Efficient cellular MR enhancement
• No cytotoxicity observed
Presenter
Presentation Notes
We have successfully labeled monocyte cells with these nanopartilces. The labeled cells were imaged with confocal microscopy and magnetic resonance. Flow cytometry studies indicated a >98% cell labeling efficiency while MTS viability assay suggested that the nanoparticles are nontoxic to cells even at a high loading of 123 microgram/5000 cells.
Collagen Induced Arthritis (CIA): A Rheumatoid Arthritis (RA) Model
A chronic, inflammatory, autoimmune disease that causes one’s immune system to attack the joints. Loss of mobility due to pain and joint destruction.
Infiltration of synovium by activated monocytes.
In Vivo Optical Detection
Control
Arthritic
+ saline + 250 mg/kg NP+ 125 mg/kg NP
Presenter
Presentation Notes
We have also shown that we can optically detect the accumulation of our NP in the diseased animal model.
+ saline + 5.0 mg NP+ 2.5 mg NP
0.76, p=0.0683 0.82, p=0.0128 0.89, p=0.0017
Luminescence Correlates to Clinical Index
FITC NP Merge
T-Cells(CD3)
+Collagen+NP
Monocytes (MOMA)
+Collagen+ NP
50 µm
Ex Vivo CIA Monocyte Labeling
Monocytes in the inflamed joint contain the NPs while T-cells, which are also implicated in rheumatoid arthritis, do not contain the NPs.
Kim, J. S.; An, H.; Rieter, W. J.; Esserman, D.; Taylor, K. M. L.; Sartor, R. B.; Lin, W.; Lin, W.; Tarrant, T. K. Clin. Exp. Rheum., 2009, 27, 580-580.
Presenter
Presentation Notes
Interestingly, we have shown that these particles are specific for monocyte cells over other immune cells such as T-cells, also implicated in rheumatoid arthritis. explain…
MR Image Correlation to FluorescencePre-NP 12h post-NP
3D High-Res MRI
In Vivo Fluorescence
T1
T2
Pre-NP 12h post-NP
y = 1.7072x2 + 0.5913x + 1.2192R2 = 0.9969
0
30
60
90
0 1 2 3 4 5 6 7Layer
[GdP
-FIT
C] /
[NP]
(ug/
mg)
Layer-by-Layer Self-Assembly of Multifunctional Nanoparticles
NP0
NN
NN
O
O
O
ONH O
NHO
Gd NH2
+
nSO
OO
nNN
N
O
O
OO
O
O
O
OGd
Si
OH2OH2
OO
O 1
NP1A NP1B
1
PSS
NN
NN
O
O
O
ONH O
NHO
Gd NH N
H
S
+
n
PSS 1
NP2A
Repeat
Gd-DTTA
O
O
HO O OH
1a
Kim, J.S.; Rieter,W.J.; Taylor, K.M.L.; An, H.; Lin, W.;Lin, W. J. Am. Chem. Soc. 2007, 129, 8962.
Presenter
Presentation Notes
In order to further increase the MR relaxivity of the nanoparticles, we have designed multilayered nanoparticles using polyelectrolyte self-assembly strategies. Staring out with a negatively charged NP, we can coat cationic oligomeric Gd-polymers then followed by anionic polystyrenesulfonates. We can repeat this process to put down as many as 7 bilayer structures. The multilayer growth is supported by the increase of fluorescence intensity in fluorescein-tagged cationic oligomeric Gd-polymers. We hope that the highly disordered structures will allow facile water accessibility to the Gd centers so that we can achieve high MR relaxivity.
0
4
8
12
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0 1 2 3 4 5 6 7Layer of [Gd-Polymer]n+
R (1
05 s-1
)
How to Increase Gd Loadings w/o Sacrificing Relaxivities?
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0 1 2 3 4 5 6 7 8
Layers of Gd-Polymern+
Part
icle
Dia
met
er (n
m)
1 layer 3 layer 6 layer
Presenter
Presentation Notes
TEM images show that the nanoparticles increase in size as more layers are deposited. More improtantly, the MR relaxivitity also linear increases as more layers are grown. We have therefore achieved the goal of Increase Gd Loadings w/o Sacrificing Relaxivities.
K7GRDLbL unfunctionalized
K7RGD
HT-29 Cell Targeting with RGD Peptides
Control
Presenter
Presentation Notes
Confocal microscopic images indicate that HT-29 cancer cells have enhanced uptake Of the RGD peptide-targeted particles in comparison to control particles, non-targeted LbL particles, and particles with GRD scrambled peptides.
In vitro Target-Specific MR Imaging of HT-29 Cancer Cell
No NP
Unfunctionalized LbL NPRGD LbL NP
GRD LbL NP
T1-weighted MR image
Presenter
Presentation Notes
More imaportantly, the HT-29 cells incubated with RGD-targeted LbL NPs show significant MR enhancement over the cell w/o NP, the cells labeled with LbL NPs, and the cells labeled with LbL NPs with scrambled GRD peptides. We are now getting ready to test in vivo utility of this layer-by-layer strategies with brain tumor mouse models.
2 µm G d-S i-DT T A
NN
N
O
O
OO
O
O
O
OGdSi
OH2OH2
OO
O=
Wei
ght %
Temperature (°C)
50
70
90
110
0 200 400 600
y = 28.8x + 0.17
y = 65.5x + 1.39
y = 110.8x + 1.92
y = 10.2x + 0.40
0
5
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15
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0 0.05 0.1 0.15 0.2
1/T
(sec
-1)
Concentration (mM)
Mesoporous Silica Nanospheres as MRI Contrast Agents
2.1 µmol/kg 31 µmol/kg
Mesoporous Silica Nanospheres for Multimodal in vivo Imaging
J. Am. Chem. Soc. 2008, 130, 2154-2155.
Degradable MSN-Gd Nanoparticles
=
MSN-Gd
MSN-Gd-1
=
cleaved from MSN-Gd-1 and cleared from kidney in vivo
0102030405060708090
100
0 50 100 150
Time (hours)
% R
elea
sed
Release profile in the presence of 10 mM cysteine at 37°C
y = 24.733x - 0.7162R2 = 0.9326
y = 31.127x + 1.2263R2 = 0.9983
0
5
10
15
20
25
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7[Gd] (mM)
1/T
(s-1
)
500 nm
Biodegradable Hydrogel Nanoparticles
% re
leas
e
Time (hr)
Num
ber %
Size (nm)
0102030405060
0 100 200 300 400 500
WaterEtOH3L EtOH3L Water
A B C
T1-Weighted
Release profile in the presence of 10 mM cysteine at 37°C
Manganese Nanoscale Metal-organic Frameworks
Thin Coating Thick Coating
0
20
40
60
80
100
150 250 350 450 550Temperature (°C)
Wei
ght %
Silica Coated (9147)
PVP Coated (9145B)
Uncoated Nanorods (4115)
Thicker silica coated (9148)
NHNH
NH
HNNH
O
O O
O
HN
NHNH2
HN
OOH
O
Si
O
OEtOEt
OEtNH
ON N
CO2H
HN
Cl
HN
S
SiOEt
OEtOEt
PVP
TEOS
2 2´
= =
JACS, 2008, 130, 14358.
Pre-contrast~13 minutes after
injection~65 minutes after
injection
Silica-Coated Mn NMOFs for Multimodal Imaging
deKrafft, Angew. Chem., in revision.
Iodinated NMOFs for CT Imaging
I-NMOF Iodixanol
00.10.20.30.40.50.60.70.8
0 5 10 15 20 25
% d
isso
lved
time (h)
Presenter
Presentation Notes
Single crystal x-ray diffraction of bulk MOF, PXRD shows NMOFs are crystalline
Targeted Delivery of Anticancer Drug-Containing Nanoparticles
Poor Solvent
a) PVPb) TEOS
= Tb3+=
= c(RGDfK)
NCP-1 NCP-1′
Pt
A
AClH3N
ClH3N
Pt
Cl
NH3
H3N Cl2e-
Cell deathDNA binding
Rieter, W.J.; Pott, K.M.; Taylor, K.M.L.; Lin, W. J. Am. Chem. Soc., 2008, 130, 11584.
50 nm 500 nm
NMOFs with Large Payloads of Platinum Anticancer Drugs
Preliminary inhibitory assays show that NMOFs are very effective in killing HT-29 human colon cancer cells in vitro.
We have also shown that the cytotoxicity of these particles can be enhanced by conjugating with targeting molecules.
[Pt] (µM)
% S
urvi
val
Time (h)
% R
elea
sed
0
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0.01 0.1 1 10 100
CisplatinDSCPNCP-1NCP-1'-a+c(RGDfK)NCP-1'-b+c(RGDfK)
0
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0 6 12 18 24 30 36 42 48
NCP-1NCP-1'-aNCP-1'-b
a) b)
c) d)
e) f)
Post-Synthetic Modifications of MIL-101 Nanoparticles for Targeted Delivery of Cisplatin and Optical Contrast Agents
Taylor-Pashow, K.M.L.; Della Rocca, J.; Xie, Z.; Tran, S.; Lin, W. J. Am. Chem. Soc. 2009, 131, 14261-14263.
National Science Foundation (CHE and DMR)National Institutes of Health (NCI )
UNC Cancer Research FundDARPA
DOE
Joe Della RoccaKathryn deKrafftWave WangDemin ChenCaleb KentJoe FalkowskiRachel HuxfordAnna DunnDr. Sam MaDr. Zhigang XieDr. Feijie SongDr. Min Zhang
Acknowledgements
Dr. William RieterDr. Jason S. KimDr. Kathryn TaylorKimberly PottChristie OkoruwaAthena JinSylvie Tran
March 2008
Collaborators
Terri Tarrant, MDArthritis Center
Weili Lin, Ph.D.Radiology
Otto Zhou, Ph.D.Physics
