ParaMagnetic Microspheres

Paramagnetic microspheres have the ability to increase in magnetization with an applied magnetic field and loose their magnetism when the field is removed. Neither hysteresis nor residual magnetization is observed and that provides the end use two very practical advantages:

• When the filed is removed, the microspheres demagnetize and re-disperse easily. This property allows efficient washing steps, low background and good reproducibility.
• The behavior of the microspheres is always the same whatever the magnetization cycles may be. Such behavior is a key point for automated instrument.

106-125um Magnetic Microspheres

Recently black paramagnetic microspheres have been produced in larger sizes of 10 micron to 1mm (1000um) and in dry form enabling scientists to leverage the benefits of paramagnetic particles in new applications. These highly spherical polyethylene microspheres offer the flow-ability of standard microspheres, with the ability to be separated from other materials for re-use and cleanup.

One use of paramagnetic microspheres as large as 1mm in diameter to simulate salmon eggs, Scientists are able to place them in a natural habitat, observe how they move with the water currents and then use their magnetic properties to clean them up.

SuperParamagnetic microspheres, sometimes just called magnetic microspheres or paramagnetic microspheres have become widely used in the life sciences industry (<10um diameters) for applications such as:

• Solid Phase Immunoassays
• Bacteria Detection
• High Throughput screening
• Rapid Tests
• Cell Sorting
• Biosensors
• Nucleic Acids Technology
• Microfluidics¹

Super paramagnetic microspheres used in the life science industry are supplied in solution form.

1. Merck Estapor Super Paramagnetic Microspheres Brochure

Solid Polyethylene Microspheres for Effects in Color Cosmetics

A recent article in Cosmetics & Toiletries magazine describes the use Solid Polyethylene Mirospheres for Effects in Color Cosmetics.

Flesh Tone Microspheres - Color Matched to Skin Sample

Micropsheres have been used in cosmetics for some time, primarily as fillers and exfoliators. Most recently scientists started to utilize light reflecting properties of microspheres for creating unique optical effects, such as optical blurring and wrinkle filling.  Due to light scattering effects of the spherical surface, formulating with appropriate microspheres can minimize the appearance of fine lines and uneven skin tone, due to optically reducing contrast on the skin.

The spherical shape and smooth surface of microspheres creates a low friction ball-bearing effect that gives formulations an elegant, silky feel. This ball-bearing effect promotes better blending on the skin and a more natural finish due to the enhanced slip, glide and omnidirectional spreadability, imparting a cream to powder texture. Outstanding roundness also provides lubrication during application, which enhances the tactile experience of a cosmetic product. Continue reading “Solid Polyethylene Microspheres for Effects in Color Cosmetics” »

Cosmetic Applications of Injectable Polymer Microspheres

Polymer microspheres, in particular injectable polymer particles with a diameter in the range of 30−300 μm, are becoming widely used as a biomaterial in different clinical fields, such as cosmetic surgery, reconstructive surgery, and urology.  Injectable skin fillers offer many benefits in cosmetic dermatology, allowing new forms of facial rejuvenation and wrinkle treatment without surgery. Injectable skin and wrinkle fillers are used to increase tissue volume, reduce wrinkles, and improve skin’s overall contour.

According to The American Society for Aesthetic Plastic Surgery,  two formulations of fillers that are based on microsphere technology are FDA approved for use, differing in design and expected longevity of results.  These injectable microspheres products are used for volume replacement and for deep facial wrinkles (such as the nasolabial folds.) They are not approved for use in the lips.

One of cosmetic dermatology products using injectable microspheres is ArteFill® – a new breed of dermal filler that offers longer lasting results than other cosmetic filler injections. ArteFill® (known as Artecoll® outside of the United States) is made of polymethylmethacrylate (PMMA) microspheres (miniature beads) that are suspended in bovine collagen. Tiny microspheres are made of non-resorbable polymethylmethacrylate – a biocompatable compound that has been used for years.  PMMA has been used since the early 1930s in such common procedures as dental prostheses, eye lenses, bone repair, orthopedics and in pacemakers.  PMMA microspheres are well tolerated by human tissue (no rejection). Continue reading “Cosmetic Applications of Injectable Polymer Microspheres” »

Motivations for Using Biodegradable Microspheres in Drug Delivery

In recent years there is significant interest in using biodegradable polymeric microspheres for drug delivery. Delivering drugs through biodegradable microspheres has numerous advantages compared to conventional delivery systems. While in conventional systems the drug is usually released shortly after delivery and stops working after a brief period of time, biodegradable polymer offers a way to provide sustained release over a longer time, thus eliminating the need for multiple doses and ensuring sustained and controlled drug delivery over weeks or months. Continue reading “Motivations for Using Biodegradable Microspheres in Drug Delivery” »

Porous Ceramics: Application for Polyethylene Microspheres

Background:

Usually porous ceramics are made from aluminum oxide, silicon carbide or Zirconia.  Most porous ceramics have a natural ability to fill pores by capillary action. This makes porous ceramics water accepting, thus they also are referred to as hydrophilic material. This means the pores and channels of a ceramic have a highly charged pore surface that attracts and bonds the polar molecules of water and other polar fluids. The net effect is called “wicking” — the ability to pull fluids into the material and transport that fluid by capillary forces.  The pore size directly affects the ceramic’s air entry or bubbling pressure and hydraulic conductivity. The effective pore size is determined by the minimum orifice within a channel or pore.¹

Some porous ceramic have 40-50% open porosity with a tortuous pore structure and is available in pore sizes ranging from 0.25 to 90 microns. Monolithic, single grade, aluminum oxide porous ceramic is available in 6, 15, 30, 50, 60 and 90 micron pore sizes. In addition, some ceramic membranes can use a medium pore substrate with a thin coating of fine porous ceramic membrane in 0.25, 1, 3 and 6 micron pore sizes.^{2 Continue reading “Porous Ceramics: Application for Polyethylene Microspheres” »}