16-02-2013, 02:47 PM
Medical Nanotechnology or Nanomedicine
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Nanotechnology Definition
“Branch of engineering that deals the development and use of devices , through the understanding and control of matter at dimensions in the nanometer scale length (1-100 nm) is called Nanotechnology 0r Molecular nanotechnology”. At this scale, the physical, chemical and biological properties of materials differ from the properties of individual atoms and molecules or bulk matter, which enable novel applications.In comparison, a human hair is about 100,000 nanometers in diameter.The emerging field of nanotechnology involves scientists from many different disciplines, including physicists, chemists, engineers, and biologists.
Nanomaterials
A "nano" is actually a prefix that comes from the Greek word for “dwarf”. One nanometer(1 nm) is one billionth of a meter. All materials that fall along this scale are known as either nanocrystals or nanomaterials. Two principal factors cause the properties of nanomaterials to differ significantly from other materials: increased relative surface area, and quantum effects. These factors can change or enhance properties such as reactivity, strength and electrical characteristics. It studies materials with morphological features on the nanoscale, and especially those that have special properties stemming from their nanoscale dimensions.
Nanoscale materials have feature size less than 100 nm. ”Nanomaterials" generally fall into two categories: fullerenes, and inorganic nanoparticles. The fullerenes are a class of allotropes of carbon which conceptually are graphene sheets rolled into tubes or spheres. These include the carbon nanotubes or silicon nanotubes which are of interest both because of their mechanical strength and also because of their electrical properties. Nanoparticles or nanocrystals made of metals, semiconductors, or oxides are of particular interest for their mechanical, electrical, magnetic, optical, chemical and other properties.Nanoparticles have been used as quantum dots and as chemical catalysts.
Branches of nanotechnology
• Green nanotechnology – use of nanotechnology to enhance the environmental-sustainability of processes currently producing negative externalities. It also refers to the use of the products of nanotechnology to enhance sustainability.
• Nanoengineering – practice of engineering on the nanoscale.
• Wet nanotechnology – involves working up to large masses from small ones.
Tools In Nanotechnology
The main tools used in nanotechnology are three main microscopes
◦ Transmission Electron Microscope (TEM)
◦ Atomic Force Microscope (AFM)
◦ Scanning Tunneling Microscope (STM)
• TEM : The transmission electron microscope is one that utilizes a high-energy electron beam that probes sample materials with a thickness less than 100 nanometers (nm).While some electrons are either absorbed or bounced of the material, others pass through it creating a magnified image .
• AFM : The atomic force microscope uses a small silicon tip as a probe to make images of sample material. While the probe move along the surface of the sample, the electrons of the atoms in the material begin to repel the electrons of the probe. The AFM then adjusts the height of the probe to keep the force of the sample constant.A mechanism records the movement of the probe and sends this information to a computer that will generate a three-dimensional image.
• STM : A scanning tunneling microscope uses a wavelike property of electrons known as tunneling, which allows electrons emitted from a probe to penetrate, or tunnel into, the surface of the examined object. The electrons generate a tiny electric current that the STM measures. Similar to the atomic force microscope, the height of the probe in the STM is adjusted constantly to keep the current constant.
Nano - Microphone
World reports that German engineers crafted the hearing device called “Nano-ear”, which is based on an optically trapped gold nanoparticle, to observe silent movies of bacteria, viruses and other single-celled organisms.Hence this “nano ear” serves as “nanomicrophone”.The nano-ear is a microscopic gold particle that is trapped by a laser beam. Particles can be trapped in "optical tweezers", which are formed when laser light is focused at a fixed point in space. An electric dipole moment is induced in the particle & this suspends the particle so that it no longer moves on its own. The trapped particle can be made to move from its equilibrium position by vibrations from nearby sound waves. As the frequency of sound varies, the particles also vibrate. The frequency of the sound can then be calculated by analysing how much the particle has been displaced.
Medical Nanotechnology or Nanomedicine
Nanomedicine is the 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 utilization of nanotechnology.
• To provide more effective cure with fewer side effects by means of targeted drug delivery systems.
• Nanomedicine devices will be used in¬ :
diagnosis of illness,
implanted devices to deliver drugs or hormones ,
use miniature surgeons,
tissue repair and replacement.
Nanotechnology for pollution prevention
• Synthetic or manufacturing processes which can occur at ambient temperature and pressure.
• Use of non-toxic catalysts with minimal production of resultant pollutants.
• Use of aqueous-based reactions.
• Build molecules as needed --“just in time.”
Nanoscale information technologies for product identification and tracking to manage recycling, remanufacture, and end of life disposal of solvents.