Microparticles

Microparticles

Microparticles are particles between 0.1 and 100 μm in size. Commercially available microparticles are available a wide variety of materials, including those made of ceramics, glass, polymers, and metals. One encounters microparticles everyday in nature with items such as pollen, sand, and dust. Many Microparticles can be found in your kitchen as well with items such as: flour, and powdered sugar.

Microparticles have a much larger surface-to-volume ratio than at the macroscale, and thus their behavior can be quite different. For example, metal microparticles can be explosive in air.

Microsphere are spherical microparticles, and are used where consistent and predictable particle surface area is important.

In biological systems, microparticles are small membrane bound vesicles circulating in the blood derived from cells that are in contact with the bloodstram such as platelets and endothelial cells. (see Endothelial microparticle). Because they retain the signature membrane protein composition of the parent cell, microparticles carry useful information and can be detected and characterized by Flow cytometry.

Alternative definitions for size

Although the generally accepted definition of 0.1 to 100 μm complements the size definition of nanoparticles, there are other ways to define the size.

Mathematical: as the term "micro" refers to 10 − 6, the range for micro would then be 10 − 7.5 to 10 − 4.5, or roughly 31.6 nm to 31.6 micrometers. However, general acceptance considers particles smaller than 100 nm nanoparticles.

Rounding: rules of rounding in mathematics provide an alternative for the definition. Anything larger than 0.5 μm and anything smaller than 0.5 mm is considered microparticles.

Convenient/popular: Very often particles with dimensions more than 100 nm are still called nanoparticles. The upper range may be between 300 to 700 nm, so this would give a size definition for microparticles of 0.3 to 300 μm or 0.7 to 700 micrometers.

Applications

Most people are familiar with home pregnancy test - a color appears if the test is positive. These tests make use of gold microparticles.

Manny applications are also listed in the Microsphere article.



Wikimedia Foundation. 2010.

Игры ⚽ Поможем решить контрольную работу

Look at other dictionaries:

  • identity principle of microparticles — mikrodalelių tapatumo principas statusas T sritis fizika atitikmenys: angl. identity principle of microparticles; indistinguishability principle vok. Identitätsprinzip von Mikroteilchen, n; Ununterscheidbarkeitsprinzip, n rus. принцип… …   Fizikos terminų žodynas

  • Endothelial microparticle — Endothelial microparticles are small vesicles that are released from endothelial cells and can be found circulating in the blood. The microparticle consists of a plasma membrane surrounding a small amount of cytosol. The membrane of the… …   Wikipedia

  • Optical tweezers — (originally called single beam gradient force trap ) are scientific instruments that use a highly focused laser beam to provide an attractive or repulsive force (typically on the order of piconewtons), depending on the refractive index mismatch… …   Wikipedia

  • Chang Yi Wang — Born December 19, 1951 (1951 12 19) (age 59) Taip …   Wikipedia

  • DNA vaccination — The making of a DNA vaccine. DNA vaccination is a technique for protecting an organism against disease by injecting it with genetically engineered DNA to produce an immunological response. Nucleic acid vaccines are still experimental, and have… …   Wikipedia

  • Latex (polymer) — Latex is a name collectively given to a group of similar preparations consisting of stable dispersions of polymer microparticles in a liquid matrix (usually water). Latexes may be natural or synthetic. Synthetic latexes are usually produced by… …   Wikipedia

  • Amoxicillin — Systematic (IUPAC) name (2S,5R,6R) 6 …   Wikipedia

  • Microsphere — Not to be confused with microparticle. Microsphere are small spherical particles, with diameters in the micrometer range (typically 1 μm to 1000 μm (1 mm)). Microspheres are sometimes referred to as microparticles. Microspheres can …   Wikipedia

  • Orally disintegrating tablet — clonazepam ODT blister pack and tablet An orally disintegrating tablet or orodispersible tablet (ODT) is a drug dosage form available for a limited amount of over the counter (OTC) and prescription medications. ODTs differ from traditional… …   Wikipedia

  • Microbial loop — The microbial loop describes a trophic pathway in the marine microbial food web where dissolved organic carbon (DOC) is returned to higher trophic levels via the incorporation into bacterial biomass, and coupled with the classic food chain formed …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”