An ultrafine nano particle (or nano powder or nano cluster or nano crystal) is a microscopic particle sized between 100 and 1 nano meters. In modern science Nano particle research is currently an area of intense scientific research owing to its potential in wide range of applications in bio medical, optical and electronic fields. When formed from nano particles the properties of many conventional materials change because nano particles have a greater surface area per weight than larger particles; this causes them to be more reactive to certain other molecules.
Nano particles exhibit numerous interesting and unexpected properties relative to bulk materials. Copper nano particles smaller than 50nm are considered super tough materials that do not exhibit the same malleability and ductility as bulk copper. For instance, the bending of bulk copper like wire or ribbon occurs with movement of copper atoms/clusters at about 50nm scale.
As Nano particles are minuscule enough to confine their electrons and produce quantum effects, they often have unexpected visible properties! For example gold nano particles appear deep red to black in solution as they have a very high surface area to volume ratio.
Nano particles in medicine: An estimated 130 nano tech-based drugs and delivery systems are being developed worldwide. A method being developed to fight skin cancer uses gold nano particles to which RNA molecules are attached. The nano particles are in an ointment that is applied to the skin. The nano particles penetrate the skin and the RNA attaches to a cancer related gene, stopping the gene from generating proteins that are used in the growth of skin cancer tumors. Polymer nano particles are being developed to carry the chemotherapy drug called docetaxel directly to cancer tumors. The nano particles are attracted to a protein present on many types of cancer tumors, resulting in a high rate of delivery of the chemotherapy drug to the tumors. To reduce bleeding in trauma patients with external wounds Researchers have found that aluminosilicate nano particles can by activating the blood clotting mechanism, causing blood in a wound to clot quickly. For trauma patients with internal bleeding another way to reduce the blood loss is needed. Polymer nano particles that act as synthetic platelets are being developed by Researchers at Chase Western Reserve University. It was proven by Lab tests that the injection of these synthetic platelets significantly reduces blood loss. Nano particles coated with proteins that attach to damaged portions of arteries. This could allow delivery of drugs to the damaged regions of arteries to fight cardiovascular disease.
History: Nano particles actually have a very long history, though considered an invention of modern science. In the 9th century Nano particles were used by artisans in Mesopotamia for generating a glittering effect on the surface of pots. The ancient artisans had a rather sophisticated empirical knowledge of materials. The luster was created by a metallic film that was applied to the transparent surface of a glazing. This luster is visible even today in certain cases where the film has resisted atmospheric oxidation and other effects of the elements.
In his classic 1857 paper, Michael Faraday provided the first scientific description, of the optical properties of nano meter-scale metals.