Everything about microspheres and research utilizing precision spherical particles.

Monodisperse Silica Nanospheres and Microspheres – Dry Powder

Silica nanoparticles and nanospheres are now available in distributions of less than 10% CV in the sizes of 0.25 micron, 0.5micron, 0.75 micron, 1.0 micron, 4 micron and 8 micron.

Microbeads for Fish Egg Simulation: Dispersion and Recruitment

Microbeads for Fish Egg Simulaton

Scientists who study fish require artificial micro-particles to simulate fish eggs and their behavior in water. In order to accurately simulate the fish eggs it is important to use particles of the proper size and buoyancy/density. Particles with accurate size ranges and densities are now available.

Microspheres as Bond Line Spacers in Epoxies

Microspheres as Bond Line Spacer

Spacer Grade Glass Microspheres are presently used in gas plasma displays, automotive mirrors, electronic displays, flip chip technology, filters, sporting goods equipment, calibration standards and transformer manufacturing. Every day engineers are finding new and innovative uses for bond line spacers.

High Density Glass Microspheres

Barium Titanate Glass microspheres are high density solid glass spheres. At a Density of 4.5g/cc these solid glass spheres can be used for many scientific applications where high density and optical clarity is needed. In addition to high density they also offer an index of refraction of more than 1.9.

BioCompatability of Metal Coated Spheres

For those scientists?who are looking to use silver coated materials?such as silver coated microspheres in biomedical applications, it is important to understand whether they are bio-compatable.? A selection of abstracts and article references related to the biocompatability of silver follow:

The Biocompatibility of Silver2

The experiments reported have referred to some of the characteristics of the biocompatibility of Ag. Silver has been shown to display interactions with albumin, as an example of a plasma protein, quite different from those of most metals. Such studies shed further light on the complex issue of protein adsorption on biomaterials. It has also been demonstrated that Ag at concentrations < 1 ppm exerts a considerable influence on the activity of lactate dehydrogenase, this effect being reversed in the presence of albumin. A significant but transient increase in blood levels of Ag following intramuscular implantation of the metal has been observed. This is not reflected in any raised urine level. It is proposed that the richly vascular tissue immediately surrounding the implant in the acute phase of the response gives rise to the transient increase, but a subsequent decrease in vascularity reduces this possibility. It appears that Ag released from implants following this initial period substantially remains in the local area.2

Lack of toxicologocial side-effects in silver-coated megaprostheses in humans1

Deep infection of megaprostheses remains a serious complication in orthopedic tumor surgery. Furthermore, reinfection gets a raising problem in revision surgery of patients suffering from infections associated with primary endoprosthetic replacement of the knee and hip joint. These patients will need many revision surgeries and in some cases even an amputation is inevitable. Silver-coated medical devices proved their effectiveness on reducing infections, but toxic side-effects concerning some silver applications have been described as well. Our study reports about a silver-coated megaprosthesis for the first time and can exclude side-effects of silver-coated orthopedic implants in humans. The silver-levels in the blood did not exceed 56.4 parts per billion (ppb) and can be considered as non-toxic. Additionally we could exclude significant changes in liver and kidney functions measured by laboratory values. Histopathologic examination of the periprosthetic environment in two patients showed no signs of foreign body granulomas or chronic inflammation, despite distant effective silver concentrations up to 1626 ppb directly related to the prosthetic surface. In conclusion the silver-coated megaprosthesis allowed a release of silver without showing any local or systemic side-effects.1

Specific Article?References for the biocompatability of silver are below:

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High Index of Refraction Retroreflective Glass Microspheres

Barium Titanate Glass Microspheres are excellent for use as a functional retro reflective additive to paints and coatings. Spheres with sizes of about 50 micron (~0.002 inches) mean diameter provide a small enough size for most coatings while offering a large enough size to reflective a significant amount of light. Barium Titanate Glass Spheres are offered in both partially aluminum coated retro-reflective version for addition into transparent coatings, or as uncoated glass spherical powder for uses in colored paints.

Patent Review: Process for forming hollow glass spheres up to 5mm

A process for forming hollow glass micro-spheres with walls of controllably variable thickness in a size range of 50 to 5,000 microns, embodying (1) preparation of a water slurry of finely particulated, high temperature and low temperature glass formers; (2) prilling the slurry in a vertical spray drying tower; (3) separating and supporting the individual prilled feed material; (4) heating the feed material to glassification of the high temperature glass former while maintaining appropriate geometry and shell thickness and (5) cooling the finished product. The high temperature glass former is preferably a naturally occurring soda feldspar. The process is particularly adapted to form thicker walled micro-spheres of larger size and high quality.

Advantages of Borosilicate Glass Microspheres in 0.03mm to 0.2mm sizing

Borosilicate Glass Microbeads
BSGMS 63-75 micron at 40x magnification

High quality glass microspheres for research and development are always in high demand.? In an effort to better serve scientists Cospheric recently added a complete line of high quality borosilicate microspheres, and microbeads.

Borosilicate glass offers? advantages over standard soda lime glass microbeads.

  • Roundness is >90%?? (Soda lime >85%)
  • Density is the lowest of most glasses at 2.2g/cc? (Soda Lime 2.5g/cc)
  • Very low thermal expansion coefficient? 32×10-7/?C?? (for 30-300?C)?? (Soda Lime:? 90×10-7/?C)

The high roundness, and low thermal expansion make borosilicate spheres an excellent candidate for use as spacers in epoxy bond lines, or other applications which require stability over a wide temperature range.

Borosilicate glass spheres are now offered in narrow size ranges from 0.03mm to 0.2mm with greater than 90% of the particles in range.

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Magnetic Microspheres – New Size Ranges Offered

Cospheric announces new particle size ranges for its BKPMS, Paramagnetic Microsphere product.

Thanks to customer demand for narrower particle size ranges of paramagnetic microspheres. Cospheric has added the following sizes to its extensive inventory of microspheres offered in the dry powder form:

FDA-Approved Microspheres

What makes a microsphere FDA-approved?

In order to tell whether the microsphere can be used in cosmetics, food, or medical devices it is important to look at the raw materials that are incorporated into the microsphere during manufacturing process.? For example, unpigmented or clear polyethylene microspheres supplied by Cospheric in sizes from 10 micron to 1000 micron meet the quality requirements of the US FDA as specified in 21 CFR 172.888 and 21 CFR 178.3720.? Specific grade of polyethylene used in manufacturing of these microspheres is? FDA-approved for food applications in chewing gum base, on cheese and raw fruits and vegetables, and as a defoamer in food.

Color additives are subject to a strict system of approval under U.S. law (FD&C Act), sec. 721; 21 U.S.C. 379e. Color additive violations are a common reason for detaining imported cosmetic products offered for entry into this country. If a product contains a color additive, by law [FD&C Act, Sec. 721; 21 U.S.C. 379e; 21 CFR Parts 70 and 80] you must adhere to requirements for:

  • Approval. All color additives used in cosmetics (or any other FDA-regulated product) must be approved by FDA. There must be a regulation specifically addressing a substance’s use as a color additive, specifications, and restrictions.
  • Certification. In addition to approval, a number of color additives must be batch certified by FDA if they are to be used in cosmetics (or any other FDA-regulated product) marketed in the U.S.
  • Identity and specifications. All color additives must meet the requirements for identity and specifications stated in the Code of Federal Regulations (CFR).
  • Use and restrictions. Color additives may be used only for the intended uses stated in the regulations that pertain to them. The regulations also specify other restrictions for certain colors, such as the maximum permissible concentration in the finished product.

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