Density marker beads offer enable excellent stratification, and bright coloration for high visibility with the unaided eye.

Density marker beads of accurately known mass density are generally used as an external marker to facilitate the monitoring of the density gradient shape and range. Historically density calibration beads in the size ranges of 212-250um or 250-300um are used.

The density marker beads provide a rapid, simple, and accurate method for measuring the density. Generally a set of several such beads, covering a range of densities, is used. In the biomedical industry researchers are sometimes looking for cells having targeted specific gravities. In order to locate these cells in test tubes it is useful to have colored marker beads which will show where the delineation between specific densities occurs. Density marker beads are also used for calibrating particles in other industries, such as agriculture, microbiology and others.

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Density Marker Beads for Creation and Analysis of Density Gradients - In stock.

Density marker beads are small colored microspheres of known mass density that are used for calibrating density gradients and determining density in gradient columns. Density gradients are often used for separations and purifucations of cells, viruses and subcellular particles. Generally a set of several density marker beads covering a range of densities is used.

The gradient is calibrated with beads that float at different heights within the column. When a test sample is added to the column it drops until the point of neutral buoyancy and the density is determined from the calibration chart. Density gradient columns can be used to measure the density of any sample.

Cospheric Density Marker Beads are provided at a 20% concentration in an aqueous solution in 2.5ml vials. Unlike density marker kits which used to be manufactured by GE Healthcare and have been discontinued, the Cospheric's colored microspheres are ready for use right out of the vial, don't need to be swollen, will work with any media, and do not change density over time.

Resources on Creating Density Gradients:

Biotechnology: Theory and Techniques, Volume I (Jones and Bartlett Series in Biology)
by Jack Chirikjian and Chirikjian (Jan 1, 1995)
Pages 45-50 on Density Gradient Centrifugation.