Colloidal gold has been used for years to help scientists
diagnose and detect certain conditions in the human body. Many of these
conditions are detectable because they generate a number of particular
hormones and proteins within human cells. In order to find these
molecules, scientists will use other proteins called antibodies which
bind to their target. These antibodies have attached to them a reporter
group so that when the antibody binds to its target, the attached label
is brought along for the ride. By visualising this label, scientists can
then tell where the target hormone or protein is.
Many popular diagnostic tests use gold colloid labels. One such example is pregnancy tests, which are used by millions worldwide. The gold contained in these tests is truly microscopic (typically between 1 and 30 nm in diameter, and hence are referred to as "gold nanoparticles") and is bound electrostatically to the antibody. Using a technique called electron microscopy these antibodies can be seen because the gold nanoparticles are a lot more electron-dense than tissue or cells.
Colloidal gold is often prepared by reducing down a simple gold salt solution, such as potassium tetrachloroaurate. During this process, small particles of gold are formed which overall have a negative charge (this negative charge is believed to be derived from dichlorogold binding to the outer surface). The size of these particles can be controlled by using additives in the solution, one such example is tannic acid. As proteins (e.g. antibodies) normally have a positive charge in a near neutral pH solution, they are attracted to the negatively charged surface and adhere to it. By absorbing antibodies to the colloidal gold surface, immunogold probes are prepared. These gold proteins are then able to bind to a specific target such as the surface protein of a tumour cell, enabling them to label the antigen.
Colloidal gold itself is a very sensitive reagent, and is also used in the production of many everyday products and some dietary supplements. What makes gold so important in today's modern world is its diversity - many different characteristics can be achieved just by varying the size of the gold nanoparticles. The molecular recognition characteristics of colloidal gold make it the perfect substance for use in pregnancy tests, blood tests and other diagnostic tests.
If you are interested in the properties of colloidal gold or how it could benefit your research or business, there are a small number of manufacturers in the UK producing high quality colloidal gold.
Many popular diagnostic tests use gold colloid labels. One such example is pregnancy tests, which are used by millions worldwide. The gold contained in these tests is truly microscopic (typically between 1 and 30 nm in diameter, and hence are referred to as "gold nanoparticles") and is bound electrostatically to the antibody. Using a technique called electron microscopy these antibodies can be seen because the gold nanoparticles are a lot more electron-dense than tissue or cells.
Colloidal gold is often prepared by reducing down a simple gold salt solution, such as potassium tetrachloroaurate. During this process, small particles of gold are formed which overall have a negative charge (this negative charge is believed to be derived from dichlorogold binding to the outer surface). The size of these particles can be controlled by using additives in the solution, one such example is tannic acid. As proteins (e.g. antibodies) normally have a positive charge in a near neutral pH solution, they are attracted to the negatively charged surface and adhere to it. By absorbing antibodies to the colloidal gold surface, immunogold probes are prepared. These gold proteins are then able to bind to a specific target such as the surface protein of a tumour cell, enabling them to label the antigen.
Colloidal gold itself is a very sensitive reagent, and is also used in the production of many everyday products and some dietary supplements. What makes gold so important in today's modern world is its diversity - many different characteristics can be achieved just by varying the size of the gold nanoparticles. The molecular recognition characteristics of colloidal gold make it the perfect substance for use in pregnancy tests, blood tests and other diagnostic tests.
If you are interested in the properties of colloidal gold or how it could benefit your research or business, there are a small number of manufacturers in the UK producing high quality colloidal gold.
Advances in technology are making colloidal gold a very important mineral in the world of science and health. Get in touch to find out more.
0 comments:
Post a Comment