Nanotechnology kỹ thuật nano

• Preparation of photoactive ITO-H2P-C60 electrodes• Irradiation using visible light injects electrons into the ITO slide, through direct and indirect mediation • Applied in light harves

NANOTECHNOLOGY-BASICS AND ITS APPLICATION IN MEDICINE

Keith ó Proinsias

What is Nanotechnology?

What is Nanotechnology?

The word “Nanotechnology” is new, its existance

has been around for a long time

• 29th December , 1959

• At the annual meeting of the American Physical Society

at California Institute of Technology

“ There’s plenty of room at the bottom ”

• Richard P Feynman

• Known as the “father of nanotechology”

Why Nanotechnology?

• Medical

• Bio-materials

• Drug delivery

• Energy and industrial

• Solar / Fuel Cells

NanoparticlesQuantum dotsNanotubesFabrication

• A nanoparticle is a microscopic particle

with at least one dimension less than 100nm

• Nanoparticles are of great scientific interest as

they are effectively a bridge between bulk

materials and atomic or molecular structures

• Gold nanoparticles exhibit vast medical/health advantages

www.sciencedaily.com/articles/n/nanoparticle.htm

• Display unique optical and electrical

properties due to their size

• Fabricated using the “bottom up”

approach

Quantum Dots

• Emission of photons under excitation, which are visible

• Emission depends on size not on the material

“Size Matters”

• Smaller the dot – blue end of spectrum

• Larger the dot – red end of spectrum

• They can also be tuned

beyond visible light to

IR or UV

Quantum Dots

• Applications:

• Medical imaging and disease detection

• Produce inexpensive, industrial quality white light (e.g LEDs)

• Solar cells and photovoltaics

Quantum Dots and Porphyrins

• Porphyrins adsorbed onto CdTe quantum dots

• Results indicate that these type of porphyrin/dots can be used

as photosensitizes in photodynamic therapy

Journal of colloid and interface, 2010, 344, 596-602.

• Also known as “Fullerene”

• A round molecule consisting of

Buckeyball and Porphyrins

• Preparation of photoactive ITO-H2P-C60 electrodes

• Irradiation using visible light injects electrons into the ITO slide, through direct and indirect mediation

• Applied in light harvesting

Nano lett., 2002, 2, 965-968.

Carbon Nanotubes

• Sheets of graphite rolled into a tube

• Single walled nanotubes (SWNT)

can have a diameter of 2nm and

a length of 100µm

• There are different types of

carbon nanotube structures,

a) armchair

b) zigzag

c) chiral

Carbon Nanotubes and Porphyrins

• Prepared carbon nanotubes linked to Zn-porphyrins via the click reaction

• Applied in light harvesting

J Am Chem Soc., 2009, 131, 15394-15402.

• Covalently bonded porphyrins to carbon nanotubes

• Construct novel photovoltaic devices and light-harvesting systems

J Am Chem Soc., 2005, 127, 6916-6917.

Fabrication at nano scale

Two approaches to fabricating at nano scale,

1 Top Down

2 Bottom Up

Nano Scale Fabrication: Top Down

• Similar to a sculptor cutting away at a block of

• Radiation is shone through a template onto a surface

coated with radiation-sensitive resist

• The resist material usually consists of polymer

polymethyl methacrylate

• The resist is then removed

• The surface is chemically treated to produce the nanostructure

Nano Scale Fabrication: Bottom

Down

• Employs “self-assembly” process

• Under specific conditions the atoms and

molecules arrange themselves into the product

Self Assembly

• Originated from a process that occurs naturally in all living systems

• e.g Protein formation – formed via successive addition

of hundreds of amino acids

• Advantages:

• Rapid construction

• Occur automatically performed under mild conditions

Self Assembly: mono/multilayer

• An example of such self assembly is “self assembled monolayer's”

• Molecules are organized in an orderly fashion

• The addition of further layers, forming multilayer's, is possible

Multilayer Assembly

Zynek, M.; Serantoni, M.; Beloshapkin, S., Dempsey, E.; McCormac, T Electroanalysis, 2007, 19, 681-689

• Ruthenium metallodendrimer as the countercation within a mixed

addenda Dawson type heteropolyanion based multilayer assembly

• Preparation of a multilayer system that possesses electrocatalytic

ability towards the reduction of iodate

Fabrication: Carbon Nanotubes

• Three methods:

• Laser evaporation: within a quartz tube containing

argon gas and the graphite target, its heated to

1200oC

• Carbon arc: a potential is applied across two carbon

electrodes under 500 torr of pressure Carbon atom from the positive electrode form nanotubes on the

negative electrode

hydrocarbon gas (CH4) at 110oC

Nanomedicine

Advantages:

• Suitable for encapsulation

• Release drugs in a controlled manner

• More efficient uptake of cells

Nanomedicine: Nanoshell

• Effective drug delivery to various parts of the body is directly affected by particle size Therefore, nano-structures have the potential to enhance drug bioavailability

• Strategy:

• Attach monoclonal antibiotics or cell-surface receptors ligands that bind specifically to molecules found on the surface of the cancer

Nanomedicine: Nanoshell

• Nanoscale drug delivery can be implemented:

• Pulmonary therapies

• Gene delivery vectors

• Stabilization of drug molecules that would otherwise degrade too rapidly

• Nanoparticles are already used for target drug delivery which enables early detection

• e.g Abraxne (active ingredient is paclitaxel) uses nanoscale particles of the natural protein albumin and can be delivered without the use of solvents

Nanomedicine: Nanoshells

“Tumor detection”

• Used to target tumors and provide detection using SERS (surface enhanced Raman spectroscopy) in vivo

• The nanoparticles are encapsulated with a

thiol-modified polyethylene glycol coating for stability

• And they are conjugated with an antibody to increase selectivity to tumor cells

S S S S S S S S

S S S S S S S

HS

S

S S

S S S S S S S S

S

HS HS

Nanoshell and porphyrin

Nanomedicine: Nanoshells

• Incorporation of porphyrin molecules into nanoshells can

be used in clinical applications for imagery and therapy

Advanced Drug Delivery Reviews, 2010, 62, 1094-1124

Nanomedicine: Nanogels

• A mixture of nano-siezed particles within a gel usually protein based

• Ability to cross into cells of living organisms

• Uniformed network of crosslinked polymer chains within

a spherical nanoparticle

• Incorporate “targeting groups” (cancer treatment)

Nanomedicine: Nanogels

• Example of formation:

• Using atom transfer radical polymerization (ATRP)

• Allows precise regulation of composition and

architecture of polymers created

Nanogel and porphyrin/cobalamin

• Synthesis of biocompatible

nanogels, using intra/intermolecular disulfide cross linking with PDS containing polymers

• Noncovalently encapsulate dye

molecules, which can be released in response to a redox trigger,

glutathione (GSH)

• Encapsulate a hydrophobic

chemotherapeutic drug, Doxorubicin

J Am Chem., 2010, 132, 17227-17235

• Hydrophilic chitosan-based nanogels decorated with

hyaluronate and encapsulating photosensitizers are

excellent drug-delivery systems for the selective delivery of photosensitizers to macrophages and photodynamic

destruction of cell

Journal of Controlled Release, 2010, 144, 242-250

• Synthesized Vitamin B12

dextron nanoparticales

• Found to protect

entrapped insulin

against gut proteases

Journal of controlled release, 2007, 117, 421-429.

Nanomedicine: Nanorobotics

• Nanorobotics

• Nano: small scale smart materials

• Robot: a mechanically animated machine that is capable of impossible feats

NanoMedicine: Nanorobotics

• Application:

• Early diagnosis

• Target drug-delivery

• Biomedical instrumentation surgery

“No artificial non-biological nanorobots have so far been created, it remains a hypothetical concept at this time”

www.sciencedaily.com

Thank You

Any Questions?