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Magnetic Nanoparticle Synthesis and Surface Modification for Applications in MRI By: Brian Kong
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Transcript of Cheon Lab- Summer 2015 Presentation_Brian final
Magnetic Nanoparticle Synthesis and Surface Modification for
Applications in MRI
By: Brian Kong
Table of Contents
• Zinc-doped Iron Oxide Nanoparticle• Synthesis• Ms Optimization
• Surface Modification: Silica• Controlling Thickness (TEM, DLS)• Attaching Functional Groups
• Bioapplication: MRI• T2 Contrast Agent• T1 and T2 Dual-mode Contrast Agent
Zn0.4Fe2.6O4 Nanoparticle
Average size: 11.7 nmStd. Dev.: 0.97 nm
12 nm Zn0.4Fe2.6O4 Synthesis
20 nm
Reagents: ZnCl2, Fe(acac)2, Trioctylamine, Oleylamine, Oleic Acid
Zn0.4Fe2.6O4 Nanoparticle
Optimization of saturation magnetization (Ms)
J. Cheon et al. Angew. Chem. Int. Ed. 2009, 48, 1234-1238.
Magnetic characteristics are crucial for the successful performances of magnetic nanoparticles in biomedical applications such as magnetic resonance imaging (MRI), drug delivery, cellular signaling, and hyperthermia.
• Why?– Bioapplication in MRI – Shift from organic solvent to DIW (Biological environment)
• Method– 1. Cyclohexane– 2. Igepal CO-520– 3. MNP– 4. NH4OH– 5. Tetraethyl orthosilicate (TEOS)
Surface Modification: Silica
Silanization with TEOS (Tetraethyl orthosilicate)
- Process of covering a surface through the self-assembly of organofunctional alkoxysilane molecules. - Hydroxyl groups attack and displace the alkoxy groups on the silane thus forming a covalent -Si-O-Si- bond.
TEOS (Tetraethyl orthosilicate)
Surface Modification: Silica
Base-Catalyzed Sol-Gel reaction
12 nm Zn0.4Fe2.6O4 Zn0.4Fe2.6O4@SiO2
Control the thickness of the silica: TEM image
20 nm
Thickness average: 2.28 ± 0.63 nm
Thickness average: 7.00 ± 0.88 nm
Thickness average: 3.75 ± 0.62 nm
Thickness average: 9.58 ± 1.10 nm
20 nm
20 nm20 nm
(a) (b)
(c) (d)
Surface Modification: Silica
Control the thickness of the silica: DLS data (hydrodynamic size)
0
10
20
30
1.7362.328
3.1224.187
5.614999999999997.531
10.1
13.545
18.166
24.363
32.674
43.821
58.77178.82
0
10
20
30
1.7362.328
3.1224.187
5.614999999999997.531
10.1
13.545
18.166
24.363
32.674
43.821
58.77178.82
0
10
20
30
1.7362.328
3.1224.187
5.614999999999997.531
10.1
13.545
18.166
24.363
32.674
43.821
58.77178.82
0
10
20
30
Hydrodynamic size (nm) Hydrodynamic size (nm)
Hydrodynamic size (nm)Hydrodynamic size (nm)
num
ber (
%)
Avg. size (diameter): 23.45 nm Avg. size (diameter): 26.26 nm
Avg. size (diameter): 31.32 nm Avg. size (diameter): 38.23 nm
num
ber (
%)
num
ber (
%)
num
ber (
%)
Surface Modification: Silica
(a) (b)
(c) (d)
Attaching Functional Groups to Nanoparticles
Amine functional group
Carboxylic acid functional group
- OH - NH2
APTMS((3-Aminopropyl)triethoxysilane)
- COOH- NH2
Succinic anhydride
Bioapplications of Magnetic Nanoparticles
J. Cheon et al. Mol. Cells, 2013, 35, 274–284.
T2 MRI Contrast Agent
Silica-coated MNP
T2 Signal
Concentration
High Low
High Low
Fe conc. 1 0.5 0.25 0.125 0.0625 (mM)
- MRI is a medical imaging technique used in radiology to investigate the anatomy and physiology of the body.
- They use strong magnetic fields and radiowaves to
produce images of the body.
MRI (Magnetic Resonance Imaging)
Bioapplications of Magnetic Nanoparticles: MRI
J. Cheon et al. ACS Nano, 2014, 8, 3393–3401.
Artifacts and typical contrast agents give high contrast effects in either T1 or T2 but do not satisfy AND logic.
DMCA (Dual Mode Contrast Agent) is a core-shell design approach where the degree of T1 and T2 couplings can be modulated by a separating layer, which makes it possible to create new contrast agents with tunable and maximized T1 and T2 signals.
J. Cheon et al. J. Am. Chem. Soc., 2010, 132, 11015–11017.
T1 and T2 Dual Mode Contrast Agent
(a)
(b)
(c)
(d)
(e)
(f)
(g)
T1 and T2 Dual Mode Contrast Agent
Thickness average: 2.28 ± 0.63 nm
Thickness average: 7.00 ± 0.88 nm
Thickness average: 3.75 ± 0.62 nm
Thickness average: 9.58 ± 1.10 nm
20 nm 20 nm
20 nm20 nm
Mn3O4
Rough edges indicative of Mn3O4
Zn0.4Fe2.6O4
T2 core (12nm)
SiO2Separating
layer
(a) (b)
(c) (d)
Thank You!Special Thanks to
Graduate Student: Soojin Kim,Professor Jinwoo Cheon
and Yonsei University
for this opportunity.
