Nanotechnology

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Nanotechnology

• What is nano?
• Nanotechnology?

Creation of nanostructures Applications of the
nanostructures
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Nanofabrication techniques
Y.-P. Zhao, Growth and Synthesis of
Nanostructured Thin Films, in Functional Thin
Films and Nanostructures for Sensors edited by
A. Zribi and J. Fortin (Springer, 2008)
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Top-down

• Photo lithography
• Electron beam lithography
• Microcontact printing
• Nanoimprint
• Nanosphere lithography?
• And so on

Mask or maskless ?
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Bottom-up

• Supramolecular assembly
• nanoparticle formation
• monolayer self-assembly

The dividing line of top-down and bottom-up
sometime is vague and it is only a matter of
opinion
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Nanofabrication techniques
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Thermo-vapor transport method
A general setup for thermal-vapor transport method
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Catalyst-assisted fabrication
Deposition of a catalyst layer, e.g. thermal
evaporation of a 10 nm thick metal film or
injection of a precursor which decomposes into
particles
ZnO nanorods on Au and NiO catalysts
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Physical Vapor Deposition (PVD)
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• Thermal evaporation (resistively, electron beam)
• Sputtering (gas ion bombardment)
• Pulsed laser deposition (laser beam)

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Chemical Vapor Deposition (CVD)
Reactant gases Precursors/carrier gas
Laser beam or plasma can be introduced to
enhanced the reaction
Can fabricate carbon nanotubes, inorganic oxide
nanorods, nanowire etc.
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Liquid Phase Methods

• Sol-gel dip-coating
• Electro-spin coating
• Block-copolymer
• Electro-chemical deposition/etching

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Template-based Methods
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Kim k. et al.
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Applications

• Just name a few
• Biosensor
• Chemical sensor
• Drug delivery
• Self-cleaning
• Energy harvesting

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Biosensor glucose detection
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Biosensor bacterial/virus detection
Thank the author for sharing her research results
Junxue Fu et al 2008 Nanotechnology 19 155502
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SEM image of Si nanorods top view and side view
TEM image of Au coated Si nanorods
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Bio-functionalization of Au/Si Nanorods
antibody
dye
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Dye immobilization on Au/Si Nanorods
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Fluorescence Scan
Si rods/ Alexa488 IR
Si film/Alexa488 IF
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Salmonella detection
Sample Anti-Sal/Au/Si nanorods/Alexa488/2BSA
Salmonella
Control Au/Si nanorods/Alexa488/2BSA
Salmonella
The bacteria were fixed on the glass slides by
95 ethanol. The unbound nanorods should be
washed away by 0.05 Tween 20/FA buffer after the
incubation.
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Sample Anti-Sal/Au/Si nanorods/Alexa488/2BSA
Fluorescence Scan 532nm(ex.)/526nm SP emission
filter
Fluorescence image
Bright field image
The Alexa488 labeled nanorods (darker particles)
stick on the bacteria due to the antibody-antigen
interaction.
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Salmonella detection
Control Au/Si nanorods/Alexa488/2BSA
Fluorescence Scan 532nm(ex.)/526nm SP emission
filter
Fluorescence image
Bright field image

• The control shows there is no fluorescence signal
  since the nanorods cannot attach to the bacteria
  without the antibody.

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Lotus effect self cleaning
A
Barthlot et al. Planta 202, 1 (1997) Feng et al.
Adv, Mater. 14, 1857 (2002)
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Motivation
wings of a Cicada orni
Water striders leg
Gao et al. Nature 36, 432 (2004)
Lee et al. Langmuir 20, 7665 (2004)
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Tune the nanorod coverage
Si coverage f 32
Si coverage f 48
Deposition angle 84o
Deposition angle 88o
After coating a fluorocarbon monolayer
148o
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Water droplets bounce on a sold surface
Water droplets impacting a superhydrophobic
surface vs. a normal hydrophobic surface
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Quantum Dots for targeting
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Au nanoparticle for in vivo tumor targeting
PEG is a popular polymer in the pharmaceutical
industry for reducing nonspecific uptake of drugs
and drug-delivery systems
Qian et al. Nature Biotechnology
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