TheWorld Nano Done By: Aloysius Goh 3a3 (01). Introduction - It is the sphere of influence of nanotechnology. - Nanotechnology is the understanding and.

The WorldNano

Done By: Aloysius Goh 3a3 (01)

Introduction

- It is the sphere of influence of nanotechnology.- Nanotechnology is the understanding and control of matter at dimensions between approximately 1 and 100 nanometers, where unique phenomena enable novel applications.- Encompassing nanoscale science, engineering, and technology, nanotechnology involves imaging, measuring, modeling, and manipulating matter at this length scale.- When something is on the nanoscale, it measures between 1 - 100 nanometers (nm) in at least one of its dimensions. When things are this small, they are much too small to see with our eyes, or even with a typical light microscope. Scientists have had to develop special tools, like scanning probe microscopes to see materials that are on the nanometer size scale. Some materials have ALWAYS been on the nanoscale-like water molecules or silicon atoms.

- At the nanoscale, many common materials exhibit unusual properties, such as remarkably lower resistance to electricity, lower melting points or faster chemical reactions. For example, at the macroscale, gold (Au) is shiny and yellow. However, when the gold particles are 25 nm in size, they appear red. The smaller particles interact differently with light, so the gold particles appear a different color. Depending on the size and shape of the particles, gold can appear red, yellow or blue.

Gold Coin Nanoparticles of gold in solution

- aluminum (Al) is the shiny pliable metal used to make soda cans. At the nanoscale, aluminum particles are extremely reactive and will explode. Nanoparticles are more reactive because they have more surface area than macroscale particles.

Nano Gold

- Gold is dense, soft, shiny and the most malleable and ductile pure metal known. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water.- A small sample of the same gold is quite different, providing it is tiny enough: 10 nm particles absorb green light and thus appear red. The melting temperature decreases dramatically as the size goes down. Moreover, gold ceases to be noble, and 2-3 nm nanoparticles are excellent catalysts which also exhibit considerable magnetism. At this size they are still metallic, but smaller ones turn into insulators. Their equilibrium structure changes to icosahedral symmetry, or they are even hollow or planar, depending on size.

- Generally, gold nanoparticles are produced in a liquid ("liquid chemical methods") by reduction of chloroauric acid. After dissolving chloroauric acid, the solution is rapidly stirred while a reducing agent is added. This causes Au3+ ions to be reduced to neutral gold atoms. As more and more of these gold atoms form, the solution becomes supersaturated, and gold gradually starts to precipitate in the form

of sub-nanometer particles. The rest of the gold atoms that form stick to the existing particles, and, if the solution is stirred vigorously enough, the particles will be fairly uniform in size.

Making Colloidal Gold From Gold Wire

- Implantation of gold beads near arthritic hip joints in dogs has been found to relieve pain.- Combination of microwave radiation and colloidal gold can destroy the beta-amyloid fibrils and plaque which are associated with Alzheimer's disease.- In cancer research, colloidal gold can be used to target tumors and provide detection using SERS (Surface Enhanced Raman Spectroscopy) in vivo.

The gold is placed on the medial and lateral side of the joint

SERS

Applications in Health & Medical

- studies by numerous investigators are demonstrating that gold nanoparticles have real promise as anticancer agents. When irradiated with light, gold nanoparticles become hot quickly, hot enough to generate explosive microbubbles that will kill nearby cancer cells, a physical process known as the photothermal effect.

Photothermal Effect

- Using silver chloride nanowires decorated with gold nanoparticles, a scientist has created visible-light catalysis that may decompose organic molecules in polluted water.- Silver nanowires have been extensively studied and used for a variety of applications, by adding gold nanoparticles, they become photocatalytic in visible light. The visible light excites the electrons in the gold nanoparticles and initiates reactions that culminate in charge separation on the silver chloride nanowires.

Applications in Technology

The gold-coated silver chloride nanowires at the microscopic level.

- Gold nanoparticles designed to detect proteins within cells, using just laser light, could enable simple and highly sensitive monitoring tools for blood clots and other disorders.- The sensor consists of a silica core, 120 nanometers in diameter, encapsulated in a thin layer of gold. Mounted on the gold shell are aptamers, when a laser is shone on

the aptamer, the molecule absorbs light and reemits it with a characteristic spectrum, called its "Raman signal." When the aptamer binds with a protein, its conformation changes and subsequently changes the emitted spectrum. The sensor's gold surface amplifies the signal by increasing changes in the electric field in response to

the laser light.

Internal ingots: Gold nanoshells (black spheres) designed to detect specific proteins cluster in the cytoplasm of a mouse fibroblast cell.

Is ipod nano example of nanotechnology ?- Nanotechnology-enhanced products are already finding thier way to the market. But,

not every product labeled "nano" really utilized nanotechnolgy. Some manufacturers are using the prefix "nano-"to communicate the relative small size of their specific products to potential buyers. In addition, they hope to capitalize the buzz and excitement that has surrounded nanotechnology. For example, Indian carmakers recently introduced the Tata Nano:

- A more common example is the iPod Nano, this music player is not "nano-sized" but

it is much smaller than the orginal iPod. However, it does utilize nanotechnology in the chips and circuitry that make it work--the same way your laptop does!

References

• http://mrsec.wisc.edu/Edetc/nanotech/index.html

• chemistryland.com

• defensetech.org

• alliedwaste.ie

• jobwerx.com

• pcauto.com.cn

• jsthaiamulet.com

• beaut.ie

• http://en.wikipedia.org/wiki/Gold

• http://www.scitopics.com/Nanogold_chemistry.html

• http://en.wikipedia.org/wiki/Colloidal_gold

• http://www.youtube.com/watch?v=mK4xL8D66Xg

• http://www.alchemistsworkshop.com/id2.html

• http://www.colloidalgold.com/

References

• http://www.durkesanimalhospital.com/Elbow/tabid/60/Default.aspx

• http://nanogloss.com/nanoparticles/gold-nanoparticles-101/

• http://www.physorg.com/news194078270.html

• http://www.photonics.com/Article.aspx?AID=42539

• http://www.technologyreview.com/biomedicine/25031/?a=f

Thank You