Everything about Microspheres
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  • Negatively-charged Yellow Microparticles – Back in Stock

    Highly Negative Charged Microspheres - Polyethylene, Selection of Sizes 5 to 500um

    Highly Negative Charged Microspheres - Polyethylene, Selection of Sizes 5 to 500um, 1.0g/cc

    Cospheric’s neutrally-buoyant highly charged yellow microspheres have a strong negative charge and are used by scientists in medical technology, biotechnology, applied physics and research. Precise particles with known density of 1.0g/cc that behave in a known way are useful as a model particles in simulation experiments.  Particles in a range of diameters from 5micron to 500micron(0.5mm) are currently back in stock.

    Bright yellow polymer microparticles of high sphericity are spherical polyethylene beads that are specifically designed with density ~1.0g/cc for suspension in fresh water,  serving as seed or tracer particles and enabling flow visualization and Particle Image Velocimetry PIV analysis of fluid flow in a device. It is often advantageous to color code the particles by size to better understand which part of the process the spheres of the specific size were able to pass through, or where the contamination in the process is coming from. Microspheres are supplied in dry powder form and are color stable in solution. No solvents are used in the manufacturing process. Polyethylene is inert to most solvents.

    Cospheric also offers unique capability to manufacture Bichromal janus microspheres and microparticles with partial coatings and potentially dual functionality. Currently half-shell or hemispherical coatings can be applied to any sphere (glass, polymer, ceramic) in sizes 45micron in diameter and higher. Coatings can be customized for any color and coverage of between 20% to 60% of the sphere. Each coating is custom formulated for color, charge, magnetic, electric, and surface properties, and solvent resistance per customers’ needs. Hemispherical coatings of less than 1 micron with tolerances as low as 0.25 micron have been routinely demonstrated.  Color combinations are truly unlimited. White, black, silver, blue, green, red, yellow, brown, purple as well as transparent microspheres have been made. Sphericity of greater than 90% and custom particle size ranges are offered.

    It would be interesting to combine these highly charged yellow microspheres with a partial paramagnetic black coating and investigate the behavior of these spheres in electromagnetic field.

  • Measurement Techniques for Electrostatic Charged Microspheres

    Charged Microspheres Measurement TechniquesElectrostatic charge (also known as triboelectric charge) on microparticles and microspheres have been of interest to scientists in chemical, pharmaceutical, cosmetic, drug delivery, displays and other industries for many years. Until recently there were no reliable techniques to measure or quantify electrostatic charge on microparticles, with too many uncontrolled variables the measurements were inconsistent. As a result scientists were treating charging as a black box process, performing the experiments blindly as trial and error. With recent advances in microsphere manufacturing, techniques have been developed that promise not only to quantify the charge on microspheres, but control it in the manufacturing process.

    Continue reading “Measurement Techniques for Electrostatic Charged Microspheres” »

  • Electrostatic-based DNA Microarray Offers Medical Diagnostics Capabilities

    The uses for microspheres continue to grow, a recent article published by UC-Berkley shows how DNA sequencing can be achieved through the use of statically charged microspheres.   The key breakthrough is that they have been able to achieve a visible result through using the electrostatic repulsion of the microspheres.   A copy of their announcement follows:

    Groves,  and members of his research group Nathan Clack and Khalid Salaita, have published a paper on their technique in the journal Nature Biotechnology, which is now available online. The paper is entitled “Electrostatic readout of DNA microarrays with charged microspheres.Continue reading “Electrostatic-based DNA Microarray Offers Medical Diagnostics Capabilities” »