Download Nanotechnology

“Nanotechnology”
(Lecture 1)
Shagufta Kanwal
Evolution of Technologies
2 2
Nanotechnology?
“Ability to work at the atomic, molecular and
even sub-molecular levels in order to create
and use material structures, devices and
systems with new properties and functions”
Source: National Science Foundation (NSF), USA
3
A Journey to the World of
NANOTECHNOLOGY…
What is Nanotechnology?
“Art and science of manipulating atoms and molecules to
create new systems, materials and devices with at least
Richard Feynman
one feature of less than 100 nm scale (critically 10 nm)”.
Idea given by Richard Feynman in his famous speech in 1959
“There is a plenty of room at the bottom” at Caltech, USA.
Nature employs nanotechnology to build nanoscale DNA,
proteins and enzymes etc.
Ribosome is an ideal example of nanomachine (nanorobot).
How to differentiate between nano-biotechnology and
What isbio-nanotechnology?
the function of ribosome?
NanoBiotechnology?
Nanobiotechnology is the branch of nanotechnology
with biological and biochemical applications or uses.
Nanobiotechnology often studies existing elements of
nature in order to fabricate new devices.
Nanobiotechnology usually refers to the use of nanotechnology to further
the goals of biotechnology, while bionanotechnology might refer to any
overlap between biology and nanotechnology, including the use of
biomolecules as part of or as an inspiration for nanotechnological devices.
Nanobiotechnology is that branch of one,which deals with the study and
application of biological and biochemical activities from elements of
nature to fabricate new devices like biosensors. Nanobiotechnology is
often used to describe the overlapping multidisciplinary activities
associated with biosensors particularly where photonics, chemistry,
biology, biophysics nanomedicine and engineering converge.
EXAMPLE: Nanospheres coated with fluorescent polymers. Researchers are
seeking to design polymers whose fluorescence is quenched when they encounter
6
specific molecules.
“Nanotechnology is an enabling technology that
will change the nature of almost every humanmade object in the next century.”
National Science and Technology Council, USA
http://www.directionsmag.com
8 8
Evolution of Nanotechnology:
The ability to work at the molecular level, atom by
atom, to create structures with fundamentally new
molecular organization.”
• The Nanoscale was initially used by R. P.
Feynman, a physicist.
“There’s plenty of room at the
bottom. But there’s not that much
room - to put every atom in
its place - the vision articulated by
some nanotechnologists - would
require magic fingers”.
Nanoscale Measurements!
What Does a Nano Mean?
“Nano” – derived from a Greek word “Nanos” meaning DWARF or small.
“Nano” = One billionth of something
“A Nanometer” = One billionth of a meter = 10-9 meter
Nanotechnology
A nanometer (nm) is one billionth (10-9) of a meter
Thickness of a human hair  80,000 nm
Nanometer:10-9 m = 10 x 10-10 m = 10 atoms in a line
(one atom, 2He4  10-10 m  0.1 nm)
Electron
Sub-Nanometer Sizes:
Proton
Electron 1.986 x 10-18 m
 2 x 10-9 nm
Proton 10-15 m  10-6 nm
Neutron  10-6 nm
 1/1,000,000 nm)
Neutron
Helium Atom, 2He4
Size : 0.1 nm
15
0.1nm
16 16
Nanoscale
No.
Item
Size (Approx.),
Scaling down
µm to nm
Size (Approx.),
on nm Scale
1.
Human hair (diameter)
60 – 120 µm
60,000 – 120,000
2.
Pollen
10 – 100 µm
10,000 – 100,000
3.
Asbestos fibers (diameter)
< 3 µm
< 3,000
4.
Diesel exhaust particles
< 100 nm – 1 µm
< 100 nm – 1000
5.
Soot
< 10 nm – 1 µm
< 10 nm – 1000
6.
Quantum dots
2 – 20 nm
2 – 20
7.
Nanotubes (diameter)
~1 nm
~1
8.
Fullerenes
~ 1 nm
~1
9.
Atoms
1-3 Å ~ 0.1 nm
1-3 Å ~ 0.1
17 17
Typical Nanosizes of Cellular Species
Biological
Species
Example
Typical Size
(nm)
Typical
Molecular Weight
Small
assemblies
Ribosome
20 (sphere)
105 – 107
Nucleic acids
tRNA
10 (rod)
104 – 105
Small proteins
Chymotrypsin
4 (sphere)
104 – 105
Large proteins
Aspartate
transcarbamoylase
7 (sphere)
105 – 107
Source: Nanotechnology in Biology and Medicine, Ed: Tuan Vo-Dinh, CRC Press, 2007
18 18
Why will nano change the properties of
materials?
Example: Smaller size means larger surface area
diameter 10 µm
Area 0.22 m2/g
50 nm diameter
44 m2/g
19 19
Why nano will change the properties of materials?
Smaller size means larger surface area
Sphere
• Volume,
V = 4/3 π R3
• Surface Area, S = 4πR2
• Ratio
S/V = 3 /R α 1/R
12
11
10
9
8
7
S/ 6
V 5
4
3
2
1
0
He atom, 2R = 0.1 nm. S/V = 6 × 1010
R
0.5 1
2
3
R
4
5
R
S/V
3
1
2
1.5
1
3
0.5
6
0.25
12
0.125
24
20
How to Make Nanostructures?
Top-down Approach
Building something by starting with a larger component and
carving away material (like a sculpture)
Nanotechnology example: patterning (using photolithography)
and etching away material, as in building integrated circuits
Rock
Statue
How to Make Nanostructures?
Bottom-up
Building something by assembling smaller components (like
building a car engine), atom by atom assembly.
In nanotechnology: self-assembly of atoms and molecules, as
in chemical and biological systems
Brick
Building
Why Small is Good?
Nano-objects are:
- Faster
- Lighter
- Can get into small spaces
- Cheaper
- More energy efficient
- Different properties at very
small scale
Surface area increases as size decreases
Molecular self-assembly
Molecular self-assembly is the process by which
molecules adopt a defined arrangement without
guidance or management from an outside source.
There are two types of self-assembly:
Intramolecular self-assembly  folding
Intermolecular self-assembly.
An example of a molecular self-assembly through hydrogen bonds reported by Meijer
and coworkers.
28
Supramolecular Systems
Molecular self-assembly is a key concept in
supramolecular chemistry since assembly of the
molecules is directed through noncovalent interactions
(e.g., hydrogen bonding, metal coordination,
hydrophobic forces, van der Waals forces, π-π
interactions, and/or electrostatic) as well as
electromagnetic interactions. Common examples
include the formation of micelles, vesicles and liquid
crystal phases.
29
Biological Systems
Molecular self-assembly is crucial to the function of
cells. It is exhibited in the self-assembly of lipids to
form the membrane, the formation of double helical
DNA through hydrogen bonding of the individual
strands, and the assembly of proteins to form
quaternary structures. Molecular self-assembly of
incorrectly folded proteins into insoluble amyloid
fibers is responsible for infectious prion-related
neurodegenerative diseases.
30
Nanotechnology
The DNA structure at left will self-assemble into the
structure visualized by atomic force microscopy at
right.
31
Nanotechnology
Molecular self-assembly is an important aspect of bottom-up
approaches to nanotechnology. Using molecular self-assembly
the final (desired) structure is programmed in the shape and
functional groups of the molecules. Self-assembly is referred to
as a 'bottom-up' manufacturing technique in contrast to a 'topdown' technique such as lithography where the desired final
structure is carved from a larger block of matter. In the
speculative vision of molecular nanotechnology, microchips of
the future might be made by molecular self-assembly. An
advantage to constructing nanostructure using molecular selfassembly for biological materials is that they will degrade back
into individual molecules that can be broken down by the body.
32
DNA nanotechnology
DNA nanotechnology is an area of current research that uses the
bottom-up, self-assembly approach for nanotechnological goals. DNA
nanotechnology uses the unique molecular recognition properties of
DNA and other nucleic acids to create self-assembling branched DNA
complexes with useful properties. DNA is thus used as a structural
material rather than as a carrier of biological information, to make
structures such as two-dimensional periodic lattices (both tile-based as
well as using the "DNA origami" method (DNA origami is the nanoscale
folding of DNA to create arbitrary two and three dimensional shapes at
the nanoscale. The specificity of the interactions between
complementary base pairs make DNA a useful construction material
through design of its base sequences) and three-dimensional structures
in the shapes of polyhedra. These DNA structures have also been used to
template the assembly of other molecules such as gold nanoparticles and
streptavidin proteins (bacteria uses are the purification or detection of
various biomolecules.
33
Computational Nanotechnology
Goal
Develop theory, models, and large scale simulations to establish the
scientific basis and as cost-effective design tools in meeting grand
challenges in
- Nanoelectronics and computing
- Optoelectronics, photonics
- Sensors
- Structural materials
Approach
Modeling and simulation across time and length scales coupling
fundamental physics, chemistry, and material science, and validation against
experiments
34