3. Nanotechnology is a field which deals with materials and systems having at
least one dimension in the range of 1-100 nanometer(1nm=10-9
).
•Study of control of matter on an atomic and molecular scale.
•The prefix “nano” is a Greek word for “dwarf”
•One nanometer (nm) is equal to one-billionth of a meter
•About a width of 6 carbon atoms or 10 water molecules
•A human hair is approximately 80,000 nm wide
•Red blood cells is 7000 nm wide
•Atoms are smaller than 1 nanometer
4. History of nanotechnology
~ 2000 Years Ago – Sulfide nano crystals used by Greeks
and Romans to dye hair
~ 1000 Years Ago (Middle Ages) – Gold nano particles of
different sizes used to produce different colors in stained
glass windows
1959 – “There is plenty of room at the bottom” by R.
Feynman
1974 – “Nanotechnology” - Taniguchi uses the term
nanotechnology for the first time
1981 – IBM develops Scanning Tunneling Microscope
1985 – “Buckyball” - Scientists at Rice University and
University of Sussex discover C60
5. 1986 – “Engines of Creation” - First book on nanotechnology
by K. Eric Drexler. Atomic Force Microscope invented by
Binnig, Quate and Gerbe
1989 – IBM logo made with individual atoms
1991 – Carbon nanotube discovered by S. Iijima
1999 – “Nanomedicine” – 1st nanomedicine book by R.
Freitas
2000 – “National Nanotechnology Initiative” launched
6.
7. Two main approaches are used in
nanotechnology:
1.Bottom up approach (simple to complex)
•Materials and devices are built from molecular
components which assemble themselves
chemically by principles of molecular recognition.
• Arrangement is favored due to non-covalent
intermolecular forces.
•DNA nanotechnology utilizes the specificity of
Watson Crick base pairing to construct well defined
structures out of DNA and other nucleic acids
8. 2.Top-down approach
• Nano-objects are constructed from larger entities
without atomic-level control .
•A number of physical phenomena become
pronounced as the size of the system decreases
•Include statistical mechanical effects, as well as
quantum mechanical effects.
•Solid state techniques can also be used to create
devices known as NEMS
9. Nanotechnology categorized as:
Bionanotechnology - deals with interfacing functional biomolecules with available
devices for development of devices with higher performance in terms of selectivity,
sensitivity and economics.
Nanoelectronics - deals with miniaturization of present submicron semiconductor
technology with feature size below 10nm.
Nanomaterials - take advantage of entirely different chemical, physical, optical
and electronic properties of nanoparticles than bulk material.
10.
11. Medical Nanotechnology
Nanomedicine - application of nanotechnology in medicine, including to cure
diseases and repair damaged tissues such as bone, muscle, and nerve
Key goals for nanomedicine
•To develop cure for traditionally incurable diseases (e.g. Cancer) through the
utilisation of nanotechnology
•To provide more effective cure with fewer side effects by means of targeted
drug delivery systems
13. Therapeutic
•Delivering medication to the exact location
•Killing of bacteria, viruses & cancer cells
•Repair of damaged tissues
•Oxygen transport
•Skin and dental care
•Augmentation of immune system
•Treatment of Atherosclerosis
14. Diagnostic nanotechnology
Nanoparticles possess certain size-dependent properties,
particularly with respect to optical and magnetic parameters,
that can be manipulated to achieve a detectable signal .
The primary event in most nanoparticle-based assays is the
binding of a nanoparticle label or probe to the target
biomolecule that will produce a measurable signal
characteristic of the target biomolecules.
A variety of probes have been used for this
purpose, including QDs, nanoshells,
and metal nanoparticles
15. Quantum Dots
QDs are semiconductor nanocrystals (2–8 nm) , characterized
by strong light absorbance, that can be used as fluorescent
labels for biomolecules.
Structure
Semiconductor nanocrystals typically composed of a core
semiconductor enclosed in a shell of another semiconductor
with a larger spectral band-gap; a third silica shell can be
added for water solubility
Applications
Multiplexed diagnostics; immunoassays; immunohistochemical
assays; neurotransmitter detection; cellular imaging
Toxicity
Risk of leakage of toxic core semiconductor materials into host
system or into environment on disposal
16. Schematic diagram of a multiplex QD-based assay.
•Multiple antigens (Ag) can be labeled by use of primary antibodies
(Ab)conjugated to QDs with different sizes.
•One antibody may be biotinylated and detected with a streptavidin-coated
QD.
•On excitation, QDs will have different emission maxima based on their sizes.
17. Cantilevers
.
Typical AFM setup
A micro fabricated cantilever with a sharp tip is
deflected by features on a sample surface, much
like in a phonograph but on a much smaller scale.
A laser beam reflects off the backside of the
cantilever into a set of photo detectors, allowing the
deflection to be measured and assembled into an
image of the surface
Cantilevers
Small beams –function by means of
nanomechanical deflections
cantilever arrays can detect
molecular targets without the targets
being labeled.
Structure
Micro machined silicon cantilevers
similar to those used in atomic force
microscope.
18. •DNA detection by hybridization
•PSA detection
•Salmonella enterica
Cardiac troponins
Toxicity
No particular toxicity concerns
Applications
•Protein and DNA detection and
quantification
19. Gold Nanoparticles
-are associated colloids (3 to 100 nm)
- rather stable and whose properties can be easily tailored
by chemically modifying their surfaces.
Structure
Gold nanoshells consist of concenteric sphere nanoparticles
with a dielectric core (gold sulphide or silica) surrounded with
a thin gold shell
Applications
Immunoassays;detection of infectious agents by dna
hybridisation
Toxicity
No particular
20.
21.
22. Magnetic nanoparticles
•Label choice is made so that its interaction with the
analyte gives a magnetic signal.
•Detection of label is done by magnetometer
•High sensitivity - detect subtle modifications in
magnetic character.
• Ability to detect circulating cancer cells and
microorganisms
23. Nano Barcodes
•Sequential electrochemical deposition of metal ions to give
submicrometer metallic barcodes whose differential reflectivity
can lead to identification of the unique striping patterns by light
microscopy
•Used for multiplexed protein assays and single-nucleotide
variation (SNP)mapping;
• Does not interfere with use of fluorescence labeling
24. Nanowires and nanotubes
•Similar to other nanoparticles, e.g., gold and QDs, but are
characterized by having different shapes, thus allowing for
different interactions with different entities and more
unique signals
•Can be associated with almost any chemical or biological
recognition system;
• allow real-time detection;
•analyte-independent;
•suitable for the use; in vivo diagnostics
Applications in nanodevices
•Nanoscale sensors
•Solar cells
•Transistors,diodes,lasers
25. Nanochip
• employs the power of an electronic current that
separates DNA probes to specific sites on the array
based on charge and size.
• Once these probes are on specific sites of the nanochip,
the test sample (blood) can then be analyzed for target
DNA sequences by hybridization with these probes.
•DNA molecules that hybridize with target DNA
sequences fluoresce,
detected and relayed back to an onboard system through
platinum wiring that is present within the chip.
•Detects within minutes(E.coli-4mins)
26. Microfluidics(lab on a chip)
•Composed of microfabricated fluidic channels, heaters, temperature sensors,
electrophoretic chambers, and fluorescence detectors to analyze nanoliter-size
DNA samples.
•DNA sample is completely unknown
• Combination of numerous processes of DNA analysis are combined on a
single chip( single glass and silicon substrate.)
27. •Capable of measuring aqueous reagent and DNA-containing solutions,
mixing the solutions together,
• Amplifying or digesting the DNA to form discrete products,
• And then separating and detecting those products
Example of an
integrated nanoliter
device. The fluid
substrate moves from
one chamber to the
next for processing by
delicate air pressure
controls.
28. MEMS-microelectromechanical systems
•Allow both electronic circuits and mechanical devices to be manufactured
on a silicon chip,
•MEMS do not require reagents or a fluidity based substrate to react upon.
•Primarily used in drug-delivery systems
•Swallowed capsule technology pills that allow
doctors to visualize GI bleeding
A camera the size of a pill
that contains metal oxide
semiconductor particles
29. Nanorobots
•Future nanodevices for maintaining and protecting human
body against pathogens
•Diameter of 0.5-3 microns
•Will be constructed out of parts with dimensions in range
of 1-100nm
•Powering of nanorobots can be done by metabolising
local glucose and oxygen for energy
•Will have simple onboard computers capable of
performing around 1000 or fewer computations per
second
•Will distinguish between different cell types by checking
their surface antigens
•Can be retrieved by allowing them to exfuse themselves
via usual human excretory channels
30.
31.
32. GOALS
•Construction of a nanoassembler(build nanoprobes on a grand scale)
•Self replication of nanoprobes-mitosis
HEALTH AND ENVIRONMENT CONCERNS
•Silver nanoparticles(bacteriostatic) destroy beneficial bacteria imp for
breaking down organic matter in waste treatment plants
•The Center for Responsible Nanotechnology suggests that new
developments could result, among other things, in untraceable
weapons of mass destruction, networked cameras for use by the
government, and weapons developments fast enough to destabilize
arms races
