Everything about microspheres and research utilizing precision spherical particles.

Calculating microspheres per gram

During scientific experiment design and analysis it is common to need to know the number of spheres per gram of dry material. We have put together the table below to help speed up the process.

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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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

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

Technical Properties of PMMA Microspheres

PMMA Microspheres - Technical Specifications

In this article we will discuss the applications and technical properties of PMMA microspheres. What are PMMA Microspheres? PMMA micropsheres are also known as Poly(methyl methacrylate) or acrylic microspheres. PMMA, an ester of methacrylic acid (CH2=C[CH3]CO2H), is a synthetic resin produced from the polymerization of methyl methacrylate. Ever since PMMA resin was discovered and first … Read more

Fluorochromes – Excitation and Emission Wavelengths Reference Table

Below is a useful reference table of various Fluorochromes that can be used in research requiring precise responses. For more information about Fluorescent Microspheres that utilize fluorochromes please refer to the related article titled “Fluorescent Microspheres – Properties and Applications.”

The fluorochrome table is also available for download as a pdf.

Table of Excitation and Emission Wavelengths

FLUOROCHROME EXCITATION(nm)
EMISSION (nm)
3-Hydroxypyrene 5,8,10-Tri Sulfonic acid 403 513
5-Hydroxy Tryptamine 380-415 520-530
5-Hydroxy Tryptamine (5-HT) 400 530
Acid Fuchsin 540 630
Acridine Orange (bound to DNA) 502 526
Acridine Red 455-600 560-680
Acridine Yellow 470 550
Acriflavin 436 520
AFA (Acriflavin Feulgen SITSA) 355-425 460
Alizarin Complexon 530-560 580
Alizarin Red 530-560 580
Allophycocyanin 650 661
ACMA 430 474
Aminoactinomycin D 555 655
Aminocoumarin 350 445
Anthroyl Stearate 361-381 446
Astrazon Brilliant Red 4G 500 585
Astrazon Orange R 470 540
Astrazon Red 6B 520 595
Astrazon Yellow 7 GLL 450 480
Atabrine 436 490
Auramine 460 550
Aurophosphine 450-490 515
Aurophosphine G

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Fluorescent Tracer Microspheres – Properties and Applications

Fluorescent Tracer Particles

Fluorescent microspheres are round spherical particles that emit bright colors when illuminated by UV light. Ability to emit intense color under UV (black light) illumination provides contrast and visibility of microspheres relative to background materials.

What is a Microsphere? Definition and Explanation.

Sourcing Microspheres - Monodisperse Silica
Conductive Bondline Spacer - Silver-Coated Silica Spheres
Conductive Bondline Spacer – Silver-Coated Silica Microspheres (Cospheric Product ID: SiO2MS-Ag)

Definition of a Microsphere:

There is a lot of confusion and uncertainty in the academic community as well as the industry on exactly what is a microsphere. Below is the definition of “microsphere” that we use, because it is clear and straight-forward:

Microsphere is a term used for a small solid spherical particle, with diameter in the micrometer range (typically 1 micron to 1000 micron (1mm)).

What a Microsphere is Not:

A microsphere is not the same as a microcapsule, because microcapsules typically consist of a flexible (deformable) shell encapsulating a fluid, which might be liquid or gas. Microspheres always have a solid shell. Even if the microsphere is technically hollow (containing gas inside), its shape is not significantly flexible or deformable.

A microsphere is not the same as a microparticle, because microparticle is a general term that refers only to the size of the granular material and does not provide information on the shape. Microspheres are always round and spherical. There are no sharp edges, oblong shapes, or debris.

What are Nanospheres? Silica Nanospheres
Monodisperse Silica Nanospheres (Cospheric Product ID: SiO2MS)

A microsphere is not the same as a nanopshere, because nanospheres have diameters on the nanoscale (typically between 1 nanometer and 1000 nanometers (1 micron)). Nano-diameters present a complete different characteristics, behaviors, and functionalities.

What are Microsphere Materials:

Microspheres are manufactured from various natural and synthetic materials. Glass microspheres, polymer microspheres, and ceramic microspheres are commercially available. Solid and hollow microspheres vary a lot in density and, therefore, are used for different applications. Hollow microspheres are typically used as additives to lower the density of a material. Solid microspheres have numerous applications depending on what material they are constructed of and what size they are.

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