3 Scenarios When Density of Microspheres Matters in Research

Does Density of Microspheres Matter for Fluid Suspension?

When is the density of microspheres important? Density of microspheres controls the buoyancy of each particle and its behavior in a system or process. Let’s look at three scenarios: (1) suspension of microspheres in a specific fluid, (2) fluid flow, performing flow visualizations, or particle image velocimetry, and (3) simulation or modeling of objects with specific density.

Use of Polyethylene Spheres to Study Effect of Microplastics Transport in Soil

Effect on Microplastics Transport

Despite great general benefits derived from plastic use, accumulation of plastic material in ecosystems, and especially microplastics, is becoming an increasing environmental concern. Microplastic has been extensively studied in aquatic environments, with very few studies focusing on soils. Overview of the study on microplastics transport in soil: Scientists tested the idea that microplastic particles (polyethylene … Read more

Silane and Fluorochemical Coated Glass Spheres

The following products are offered in both Silane and Fluorochemical Coating.
P2011SL 3-6um mean diameter solid soda lime glass
P2015SL 8-12um mean diameter solid soda lime glass
P2050SL 35-45um mean diameter solid soda lime glass
P2075SL 65-75um mean diameter solid soda lime glass
P2453BTA 40-60um mean diameter solid barium titanate glass with aluminum shell.

Density Marker Beads

Materials of Microspheres

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.

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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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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Phosphorescent Microspheres – Long Afterglow Particles

Phosphorescent microspheres in particle sizes 10 to 600 microns are now available from Cospheric LLC. These phosphorescent particles are 90% spherical and appear to be off-white under ordinary daylight or regular room illumination.? However, when the lights are turned off these phosphorescent particles exhibit phosphorescent yellow-green after-glow. The spheres have tight particle size distributions and … Read more

Density Marker Beads – Microspheres with Specific gravity of 1.065 and 1.075

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. Two microsphere products having densities of 1.065 g/cc and 1.075 g/cc were recently released. These spheres are offered with density tolerances of ?0.005 g/cc enabling excellent stratification, and bright blue and red coloration for high visibility with the unaided eye.

Microspheres: Technologies and Global Markets

An extensive market research report titled Microspheres: Technologies and Global Markets was recently published by BCC Research marketing firm. The microspheres report examines the spherical microparticles used as components in many advanced materials and composites, in the healthcare and personal care industries, and in many specialty research and development applications. The report estimates the size … Read more