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Unit-05: NanotechnologyUnit-05: NanotechnologyUnit-05: Nanotechnology
What is Nanotechnology?
“Unimaginable things have taken place in the field of science in the past two or three years. In the field of nanomedicine, advancement in the last two to three years has been tremendous … In our overcommitment to talking about uses and applications of nanotechnology, let us make sure that the excitement about science doesn't not die.” - Bharat Ratna awardee CNR Rao
Theterm “nano” means dwarf. 1nanometer (nm) = 1 billionth of a meter = 10⁻⁹ meters. Nanoscale refers to the size range of 1 to 100 nanometers (nm). Size Comparisons: 1 Ant: 10 lakh nanometer 1 hair strand: 1 lakh nm Red Blood Cell: 100 micrometer (1 micrometer = 10 -6m) Bacteria: 1 micrometer Virus: 100 nanometer DNA strand: 10 nanometer Glucose (C6H12O6 ): 1 nanometer
Nanotechnologyisthe manipulation of matter at the nanoscale (1–100 nm) and the development of new materials with special properties.
Nanotechnology
Impact: Be stronger, lighter, and more precise. Exhibit extraordinary properties that differ from their bulk form.
Gold: Becomes reddish brown and soluble in water at the nanoscale. Silver: Kills bacteria at the nanoscale (used in antimicrobial coatings. Aluminum: Becomes combustible in nano form. Platinum: Acts as a catalyst at the nanoscale.
Examples of Material Behavior at Nanoscale
Butterfly wings Corals Spider silk Biomolecules Viruses
Natural Occurrences of Nanomaterials
Atomic
Prof Taniguchi (1959) ❖
Norio
He coined the term “nanotechnology
Richard Feynman - Father of modern nanotechnology. He published “There is plenty of room at the bottom” (referring to nano scale).
Force Microscope made nanotechnology a reality ❖ Scanning Tunneling Microscope was invented.
❖ The
microscope made it possible to see individual atoms.
History of Nanotechnology
Richard Feynman (1974)
Why do Nanoparticles Show Different Properties?
Quantum Physics Effects:Atthe nanoscale, materials followthe rules of quantum physics, unlike classical (Newtonian) physics. High Surface-to-Volume Ratio: As particles shrink, their surface area relative to volume increases, affecting energy interactions with the environment. ➢ Example: ✓ ✓ ✓
A rectangular block (20m x 10m x 10m) has surface area = 1000 m². When cut into 2 cubes (10m x 10m x 10m), surface area = 1200 m². The surface/volume ratio increases, exposing more to external influences. ➢ (^) Analogy: ✓ (^) Cutting a cube of paneer increases the exposure of soft inner parts to oil while frying. Increased Reactivity: High surface area enhances chemical reactivity. Example: Platinum becomes chemically active as a catalyst in its nano form. Methods To Reach Nano-Scale
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Top-Down Approach Breakdown of bulk matter to obtain nano-particles. It uses technologies like precision engineering and lithography. Time consuming and expensive method.
Bottom-Up Approach Build nano-structure from individual atoms or molecules. It relies on physical and chemical matter for the synthesis of nanoparticles. Faster, and more scalable in the future. Currently expensive, but likely to become cheaper. The bottom-up Up Approach is more popular and the seen as the future of nanotechnology.
Graphene v. Graphite Graphene and graphite are both forms of carbon, but they have distinct differences in terms of structure and properties.
Fig: Single-walled Carbon Nanotube (SWCNT) and Multi-walled Carbon Nanotubes (MWCNT)
They are formed by rolling up a single sheet of graphene into a cylinder, resulting in a long, thin structure with a small diameter. It was developed by Sumio Lizima in 1991. SWCNT (Single-Walled Carbon Nanotube): A single graphene sheet rolled into a tube. It is one- dimensional. MWCNT (Multi-Walled Carbon Nanotube): MWCNTs are arranged concentrically within each other. It can slide within each other without any friction making them the finest and smallest rotational motors. ➢ The nature of this structure is 3D.
Carbon nanotubes (CNTs) are considered to be one-dimensional (1D) structures.
Carbon NanoTube (CNTs)
Properties of CNT (Buckypaper): Mechanical Strength: 1000 times stronger than steel. Have one of the finest tensile strengths, making them extremely strong and durable. 10 times lighter than aluminium Electronic Property: 100 times more conductive than silver Thermal Properties: Extremely high thermal stability Can withstand 780°C in air Can withstand 2800°C in space. Applications of Carbon Nanotubes (CNT): Bulletproof / Stab-Proof Nanofibers: CNTs are used to create ultra-strong fibers for body armor, offering enhanced protection against bullets and stabbing attacks. Vein Scaffold: CNTs can be used to reinforce and support damaged tissue in medical science, acting as scaffolds to aid in tissue repair. Target Drug Delivery: It is also used for targeted drug delivery. Fireproof Layer/Coating for Electronic Chips: CNTs provide excellent heat resistance, making them ideal for creating fireproof coatings on electronic chips or on missiles. Replacing Silicon/Germanium in Electronics: CNTs are seen as alternatives to silicon or germanium in the production of nano-chips. This application can enhance the efficiency and performance of electronic devices, including gadgets and microelectronics. Heat Sink: It could also be used as a heat sink as it is one of the best heat-conducting materials.
Definition: Graphene sheets rolled into a spherical, football-like structure. Dimensionality: Zero-dimensional (0D) nanomaterial. Discovery: Named after the American architect Buckminster Fuller due to its structural resemblance to geodesic domes. Structure: Contains both hexagonal and pentagonal carbon arrangements.
Fullerene
Key Variant C ₆₀ (Buckminsterfullerene): The most stable and well-known fullerene, composed of 60 carbon atoms arranged in a nearly perfect spherical shape. Other Variants: C₂₀, C₇₀, etc. Fig: Fullerene contains hexagonal and pentagonal structures sometimesevenreferred to as
Properties of Fullerenes: "buckyball".
Mechanical Strength: Exhibits exceptional strength. Electrical Conductivity: Can behave like a superconductor under certain conditions. Photoreactivity: Gets activated when exposed to heat or light, which makes it useful in cancer treatment applications.
Gas Adsorption: Capable of adsorbing gases, useful in environmental^ applications.
Common Nanocarriers
Example: DRDO & IISc Bangalore: Developed a typhoid detection kit using nanosensors. ✓ (^) Cornell University (USA): Created nanomedicine that targets cancer cells in the bloodstream.
Liposomes: A liposome is a closed, spherical lipid bilayer (double layer), which forms an internal cavity capable of carrying aqueous solutions. Liposomes are now considered the most commonly used nanocarriers for various potentially active hydrophobic and hydrophilic molecules due to their high biocompatibility, biodegradability, and low immunogenicity.
Nanomicelles: Have a hydrophilic outer shell and a hydrophobic core — ideal for drug delivery due to their dual nature.
Nano-Scaffold: Used in artificial organs and prosthetics by creating nano-patterned structures. Nano-Biotech: Enhances gene therapy by correcting DNA
mutations and increasing efficacy Fig: Liposome
Nano-Hydrogel: Speeds up wound healing by enhancing cell
division ( used in tissue engineering). Example Feinbery School
of Medicine (USA)
- Energy Sector
➢ Nano Solar Cell: Normal solar cells harvest energy from visible light but nano solar cells are made of graphene and Carbon NanoTube (CNTs) and can harvest energy from infrared, and ultraviolet light (UV). Hence, increasing the energy production. ✓ Internal resistance will be minimal which will make it more energy^ efficient. ✓ Nano solar cells are very thin and can be spread like a bedsheet or^ painted over a wall.
❖ Hydrogen Fuel Cell: In this cell, hydrogen is used as a fuel, and oxygen is used as an oxidizer. Water is released as a by-product.
Fuel Cell:- Similar to batteries, a fuel cell is a device that converts energy stored in molecules into electricity through an electrochemical reaction. Composed of two electrodes (an anode and a cathode) separated by an electrolyte membrane, a typical hydrogen fuel cell works in the following way: Hydrogen enters the fuel cell via the anode. Here, hydrogen atoms react with a platinum catalyst and split into electrons and protons. Oxygen from the ambient air enters on the other side through the cathode.. The positively charged protons pass through the porous electrolyte membrane to the cathode. The negatively charged electrons flow out of the cell and generate an electric current. In the cathode, the protons and oxygen then combine to produce water. Fuel cells generate electricity through an electrochemical reaction, they are a clean source of power.
❖ Nano Zeolite: Zeolite are naturally occurring crystalline aluminosilicates. It breaks down crude petroleum into high-grade gasoline. It is a porous mineral that acts as a filter and catalyst in water purification. ➢ Since natural zeolite is scarce, scientists suggested nano zeolite with a^ bottom-up approach.
- Environment Sector ➢ Combined Use of Nano Solar Cells + Hydrogen Fuel Cells ✓ (^) Daytime: Nano solar cells generate electricity and split water to produce hydrogen. ✓ ✓
Nighttime: Stored hydrogen is used in fuel cells to generate electricity. Outcome: 24/7 clean energy system without harmful emissions.
➢ (^) Other Environmental Applications ✓ (^) Nanofabric Paper Towel: Made from potassium manganese oxide wires; can absorb oil from spills. ✓ (^) Nanosensors: Detect chemical pollutants in the environment. ▪ (^) Example: the University of Florida developed sensors to remove mercury.
▪ (^) Example: IISc Bangalore created nanochips/flakes to reduce pollutants (tested in the Mahanadi River, Odisha).
- Defense Sector
➢Nano Battle Suit: Carbon NanoTube (CNTs) are used to make bulletproof^ uniforms and helmets for soldiers. Example: Massachusetts Institute of Technology (MIT), USA in 2003 has developed soldier nanotech for making such uniforms.
Gray Goo Scenario
Blood-Brain Barrier
Nanomedicines can cross the blood-brain barrier and interfere with the functioning of our brain and other vital organs. Social Inequality: Nanomedicines can enhance the looks and immunity of a person but it will be available to the rich class only due to their high prices. Hence it can create social inequality.
The blood-brain barrier (BBB) is a protective layer that lines the inner surfaces of the blood vessels inside the brain. It’s a key part of how the brain and nervous system work. Though the name includes the word “barrier,” it’s more of a filter and behaves like a gatekeeper to the brain. It’s there to keep harmful things out and hold helpful things in. It also controls how various chemical molecules (including compounds the body needs or makes itself) enter and exit the brain.
Gray Goo Scenario: It refers to a situation where self-replicating nanobots (designed to build or repair) mutate or malfunction, consuming all matter on Earth to create more of themselves—turning everything into a mass of "grey goo." Nano Toxins: Nanotech bots developed to fight neurotoxins can go out of control and cause a green goo scenario. ➢ Green Goo Scenario: The Green Goo scenario is a theoretical risk in nanotechnology, where biologically engineered nanobots—often designed to replicate or enhance life—go out of control.
“Gray goo would surely be a depressing ending to our human adventure on Earth, far worse
than mere fire or ice, and one that could stem from a simple laboratory accident.” - Bill Joy
(co-founder of Sun Microsystems Inc. and a top computer scientist)
The risks of nanotechnology are equally awe-inspiring as its benefits, and they are
potentially existential. The best-known risk is the “gray goo” problem. It was coined by
American engineer Eric Drexler in his book Engines of Creation (1986).
“Gray goo” refers to a variety of nanotech-related disaster scenarios, all of which involve the
rapid and destructive replication of tiny nanotech molecules. In the worst case, these
molecules could turn the oceans, plant life, or even humans, into “goo.”
Issues With Nanomedicines: Nanoparticles may enter the body through inhalation, ingestion, or skin contact and cause unknown health effects.
Issues and Concerns of Nanotechnology
1. Health-Related Issues:
Nano-medicines can have side effects in our body.
It can influence with the functioning of the brain & other organs by crossing
blood-brain barriers.Side-effects were confirmed in Earthworms & human trials
are going on.
Tissue engineering, Nano-Biotech & Nano-medicine can enhance looks &
immunity of a person. It can cure diseases like cancer.It will be very costly &
available to rich people only. This will result in social inequality & this will be
against social justice.
Issues & Concerns regarding Nanotechnology
It is a general-purpose tech, which will be used at large scale in different
areas of life. This will increase the amount of nano-material in the
environment & it may lead to nano-pollution.
Nanomaterials might enter into the food chain & it can adversely impact
biodiversity. That is why all nano-material requires Environmental Impact
Assessment & evaluation before using it fully.
2. Environmental Concerns:
For Human Resource Dev & to promote fundamental research:
India's 1st INST (Institute of Nano Sci & Tech) has been setup in Mohali, PB. India's 1st Nano-park is developed in Bengaluru to attract private companies in this sector. Because of all these efforts, India was among the top 3 units in Nanotech Research. Around 23000 research papers were published in Nanotech. In India, there is a huge gap between research and the commercial value of research due to a lack of interest from the private sector.
UGC & CSIR - Provide stipend (Govt. body) during PhD.
To promote the private sector in this area, the govt is providing support to private companies by giving soft loans and providing a conducive environment.
To promote international cooperation and collaboration, ICONSAT (International Conference of Nano Sci & Tech) is organized in India, where many countries participate to promote mutual co-op in nanotech and research.
STIO: Scientists & Technocrats of Indian Origin
STIOs can be invited to different conferences and talks in India so that the country can be benefited from their expertise and position. Such people can play a very important role in international co-op and tech development in India.
Nano Weapons:-
Miniaturizing lasers, explosives, and electronic components of missiles could be deadly enough. Any military force can develop disassemblers to attack physical structures or even biological organisms at the molecular level. Linked to the "Grey Goo Scenario".
1 .Miniature weapons, Explosives & Disassemblers:
2 .If they can self-replicate - problem of limiting mechanism - they would
multiply like a virus.
3 .Erode our Freedom & Privacy (Undetected Surveillance):
Molecular-sized microphones and cameras to monitor others.
