Seminar Topics & Project Ideas On Computer Science Electronics Electrical Mechanical Engineering Civil MBA Medicine Nursing Science Physics Mathematics Chemistry ppt pdf doc presentation downloads and Abstract

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By
B.Gowtham,
Civil dept.
C.Abdul Hakeem College of Engineering and Technology,
Melvisharam.

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What are nanomaterials?
Nano = 10-9 or one billionth in size
Materials with dimensions and tolerances in the range of 100 nm to 0.1 nm
Metals, ceramics, polymeric materials, or composite materials
One nanometer spans 3-5 atoms lined up in a row
Human hair is five orders of magnitude larger than nanomaterials

Nanomaterial Composition
Comprised of many different elements such as carbons and metals
Combinations of elements can make up nanomaterial grains such as titanium carbide and zinc sulfide
Allows construction of new materials such as C60 (Bucky Balls or fullerenes) and nanotubes


Properties of C60 and its derivatives
Black crystalline solid, thermally stable up to 400 °C
Very difficult to oxidize
Doped with alkali metals: conductor and superconductor
Fluorescence
Acceptors of electrons and electronic energy

Bucky Ball properties
Arranged in pentagons and hexagons
A one atom thick seperation of two spaces; inside the ball and outside
Highest tensile strength of any known 2D structure or element, including cross-section of diamonds which have the highest tensile strength of all known 3D structures (which is also a formation of carbon atoms)
Also has the highest packing density of all known structures (including diamonds)
Impenetrable to all elements under normal circumstances, even a helium atom with an energy of 5eV (electron Volt)

Nanotube properties
Superior stiffness and strength to all other materials
Extraordinary electric properties
Reported to be thermally stable in a vacuum up to 2800 degrees Centigrade (and we fret over CPU temps over 50o C)
Capacity to carry an electric current 1000 times better than copper wires
Twice the thermal conductivity of diamonds
Pressing or stretching nanotubes can change their electrical properties by changing the quantum states of the electrons in the carbon bonds
They are either conducting or semi-conducting depending on the their structure
Nanotube uses
Can be used for containers to hold various materials on the nano-scale level
Due to their exceptional electrical properties, nanotubes have a potential for use in everyday electronics such as televisions and computers to more complex uses like aerospace materials and circuits
Applications of Nanomaterials
Next-generation computer chips
Ultra-high purity materials, enhanced thermal conductivity and longer lasting nanocrystalline materials
Kinetic Energy penetrators (DoD weapon)
Nanocrystalline tungsten heavy alloy to replace radioactive depleted uranium
Better insulation materials
Create foam-like structures called ‘aerogels’ from nanocrystalline materials
Porous and extremely lightweight, can hold up to 100 times their weight
Improved HDTV and LCD monitors
Nanocrystalline selenide, zinc sulfide, cadmium sulfide, and lead telluride to replace current phosphors
Cheaper and more durable
Harder and more durable cutting materials
Tungsten carbide, tantalum carbide, and titanium carbide
Much more wear-resistant and corrosion-resistant than conventional materials
Reduces time needed to manufacture parts, cheaper manufacturing

Even more applications…
High power magnets
Nanocrystalline yttrium-samarium-cobalt grains possess unusually large surface area compared to traditional magnet materials
Allows for much higher magnetization values
Possibility for quieter submarines, ultra-sensitive analyzing devices, magnetic resonance imaging (MRI) or automobile alternators to name a few
Pollution clean up materials
Engineered to be chemically reactive to carbon monoxide and nitrous oxide
More efficient pollution controls and cleanup
Still more applications…
Greater fuel efficiency for cars
Improved spark plug materials, ‘railplug’
Stronger bio-based plastics
Bio-based plastics made from plant oils lack sufficient structural strength to be useful
Merge nanomaterials such as clays, fibers and tubes with bio-based plastics to enhance strength and durability
Allows for stronger, more environment friendly materials to construct cars, space shuttles and a myriad of other products

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Nanomaterials


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Abstract
Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. Their unique size-dependent properties make these materials superior and indispensable in many areas of human activity. This brief review tries to summarise the most recent developments in the field of applied nanomaterials, in particular their application in biology and medicine, and discusses their commercialisation prospects.


Introduction

Nanotechnology is enabling technology that deals with nano-meter sized objects. It is expected that nanotechnology will be developed at several levels: materials, devices and systems. The nanomaterials level is the most advanced at present, both in scientific knowledge and in commercial applications. A decade ago, nanoparticles were studied because of their size-dependent physical and chemical properties .Now they have entered a commercial exploration period .
Living organisms are built of cells that are typically 10 μm across. However, the cell parts are much smaller and are in the sub-micron size domain. Even smaller are the proteins with a typical size of just 5 nm, which is comparable with the dimensions of smallest manmade nanoparticles. This simple size comparison gives an idea of using nanoparticles as very small probes that would allow us to spy at the cellular machinery without introducing too much interference . Understanding of biological processes on the nanoscale level is a strong driving force behind development of nanotechnology .
Out of plethora of size-dependant physical properties available to someone who is interested in the practical side of nanomaterials, optical and magnetic effects are the most used for biological applications.
The aim of this review is firstly to give reader a historic prospective of nanomaterial application to biology and medicine, secondly to try to overview the most recent developments in this field, and finally to discuss the hard road to commercialisation. Hybrid bionanomaterials can also be applied to build novel electronic, optoelectronics and memory devices (see for example .Nevertheless, this will not be discussed here and will be a subject of a separate article.


Applications

A list of some of the applications of nanomaterials to biology or medicine is given below:
- Fluorescent biological labels
- Drug and gene delivery
- Bio detection of pathogens
- Detection of proteins
- Probing of DNA structure
- Tissue engineering
- Tumour destruction via heating (hyperthermia
- Separation and purification of biological molecules and cells
- MRI contrast enhancement
- Phagokinetic studies
As mentioned above, the fact that nanoparticles exist in the same size domain as proteins makes nanomaterials suitable for bio tagging or labelling.However,size is just one of many characteristics of nanoparticles that itself is rarely sufficientif one is to use nanoparticles as biological tags. In order to interact with biological target, a biological or molecular coating or layer acting as a bioinorganic interface should be attached to the nanoparticle. Examples of biological coatings may include antibodies, biopolymers like collagen or monolayers of small molecules that make the nanoparticles biocompatible .In addition, as optical detection techniques are wide spread in biologicalresearch, nanoparticles should either fluoresce or change their optical properties. The approaches used in constructing nano-biomaterials are schematically presented below .


Typical configurations utilised in nano-bio materials applied to medical or biological problems.


Nano-particle usually forms the core of nano-biomaterial. It can be used as a convenient surface for molecular assembly, and may be composed of inorganic or polymeric materials. It can also be in the form of nano-vesicle surrounded by a membrane or a layer. The shape is more often spherical but cylindrical, plate-like and other shapes are possible. The size and size distribution might be important in some cases, for example if penetration through a pore structure of a cellular membrane is required. The size and size distribution are becoming extremely critical when quantum-sized effects are used to control material properties. A tight control of the average particle size and a narrow distribution of sizes allow creating very efficient fluorescent probes that emit narrow light in a very wide range of wavelengths. This helps with creating biomarkers with many and well distinguished colours. The core itself might have several layers and be multifunctional. For example, combining magnetic and luminescent layers one can both detect and manipulate the particles.The core particle is often protected by several monolayers of inert material, for example silica. Organic molecules that are adsorbed or chemisorbed on the surface of the particle are also used for this purpose. The same layer might act as a biocompatible material. However, more often an additional layer of linker molecules is required to proceed with further functionalisation. This linear linker molecule has reactive groups at both ends. One group is aimed at attaching the linker to the nanoparticle surface and the other is used to bind various moieties like biocompatibles (dextran), antibodies, fluorophores etc., depending on the function required by the application.


Recent developments
Tissue engineering

Natural bone surface is quite often contains features that are about 100 nm across. If the surface of an artificial bone implant were left smooth, the body would try to reject it. Because of that smooth surface is likely to cause production of a fibrous tissue covering the surface of the implant. This layer reduces the bone-implant contact, which may result in loosening of the implant and further inflammation. It was demonstrated that by creating nano-sized features on the surface of the hip or knee prosthesis one could reduce the chances of rejection as well as to stimulate the production of osteoblasts. The osteoblasts are the cells responsible for the growth of the bone matrix and are found on the advancing surface of the developing bone.The effect was demonstrated with polymeric, ceramic and, more recently, metal materials.