If you are starting a new research project, need some microspheres, and don't know which beads you need, we suggest that you look here first (just as you would do in a store, by first seeing what is on sale). Then, if you don't find what you need there, you can check back here in our Product Selection Guide. Ask us for help anytime along the way at 800-387-0672 or +1-317-570-7020!

This list will change frequently, so check back to see the newest bargain beads.

Search for this week's Bargain Beads.

Latex Particles, or Minibeads. Whatever you call them, we have over 2000 different microspheres made of polystyrene (PS), other polymers, copolymers, terpolymers, and silica, too. They come in a variety of densities: 0.9-2.3 g/cm³ . Production methods include emulsion or suspension polymerization, and precipitation. We sell our microspheres by weight. They are typically supplied as a 10% w/w suspension in water, so 0.5 gm will be packaged as ~5mL of 10% solids. Packaging details follow the product listings. Please ask about larger quantities!

• in Many Sizes ("from nanometers to millimeters")...
  Our microspheres are made in diameters from ~0.020-1000 µm (20 nm-1 mm). Size is most often measured size by transmission electron microscopy (TEM), supplemented by scanning electron microscopy (SEM)- for silica and photon correlation spectroscopy (dynamic light scattering or DLS), light microscopy, and sieving, where appropriate.
  
  
• with Excellent Uniformity...
  
  
• Note: The CVs of the diameters of our microspheres, where listed, were measured by TEM. CVs measured by instruments, such as dynamic light scattering (DLS), may be broader, depending on the mathematical algorithms used by these instruments. The differences are due to the fact that TEM directly measures the actual diameters of stationary particles, whereas DLS measures the interactions of materials moving in solution, then mathematically manipulates the data to calculate the mean diameter and CV.
  

		Material Safety Data Sheets Polystyrene Plain Polystyrene/DVB PMMA

Polystyrene Plain (Hydrophobic)
Polystyrene (PS) and styrene/divinylbenzene copolymer (S/DVB) plain (undyed), hydrophobic microspheres - with sulfate surface groups are used "as is" for many applications. They are used as size standards for instrument calibration or perhaps coated with proteins in a broad range of diagnostic applications- from latex agglutination test kits to sophisticated immunoassays. Ask us if you need help in coating these beads with proteins; download or request TechNote #204 for tips on adsorbing to microspheres.

Other Polymers
Polymethylmethacrylate (PMMA), polyvinyltoluene (PVT), styrene/butadiene (S/B) copolymer, styrene/vinyltoluene (S/VT) copolymer- plain (undyed), hydrophobic (sulfate surface groups): these different polymers have various densities, glass transition temperatures (softening points), and refractive indices. They are alternatives to PS and S/DVB polymers in applications where their different properties are important.

The list of larger beads includes beads made by processes which yield generally broader size distributions than the "uniform" beads above. Usually these processes are run in larger scale, and therefore lead to more economical particles. Some lots have rather narrow size ranges, i.e. 5-7 µm, while others might range from 100-400µm or 300-1000 µm.

Large Polymers
Made by suspension polymerization, most of these have a hydrophobic surface. A few have residual inorganic coatings, like colloidal silica or calcium phosphate, which make the beads hydrophilic. Ask if you want information about the surface of any lot of beads, or if you are interested in removal of the hydrophilic coating. See TechNote #203.

These range from hydrophobic (plain polystyrene), with some sulfate (-SO₄) surface groups (see previous sections), to very hydrophilic surfaces imparted by a wide variety of functional surface groups like aliphatic amine (-CH₂ -NH₂) and carboxylic acid (-COOH) [two types of carboxylate groups]. The functional groups permit a wide range of covalent coupling reactions for secure and stable attachment of peptides, proteins, oligonucleotides, and other biochemical ligands to the particle surfaces. Ask us for any help you might need in choosing the proper beads for your job. For more information on covalent coupling, download or ask for our TechNote #205.

		Material Safety Data Sheets Polystyrene Carboxyl Polystyrene Amine

Polystyrene Carboxyl
We offer three types of carboxyl functionalized microspheres: COOH/1 [P(S/V-COOH)], COOH/2 [P(S/MA)], and COOH/5. Download TechNote 205 for covalent coupling tips.

PolyLink Protein Coupling Kit
Interested in a protein coupling kit to use with your carboxyl-modified polymer or magnetic particles? PolyLink is your answer!

Polystyrene Amine
Amino functionalized or nitrogen-containing compounds, like primary, secondary, tertiary, and quaternary aliphatic amines, aromatic amines, and pyridines, offer alternative coupling reactions to the COOH beads, above.

We offer >150 different dyed microspheres in colors from red to beyond violet, as well as black and gray. Bright primary colors are available for easy color identification and mixing of colors; others are very dark, like ink, for good contrast. Ask for help with color selection and color matching. The Visible Dye Color Palette webpage supplies a color reference of our six standard visible dyes. We can make other size/color combinations, according to your need. "We will gladly dye for you!"

Our microspheres are dyed with oil-soluble dyes, dissolved in a solvent which swells the beads. The solvent is then evaporated to leave the dye stranded inside the beads. The beads are permanently dyed in aqueous suspension. We can put as much dye into the microspheres as you need and can repeat the process if necessary. TechNote #103 has more information on dyed beads.

* Color Coding: The fifth place in our catalog code denotes color. The coding is as follows: B = Blue; F = Fluorescent; G = Green; K = Black; N = None added; O = Orange; P = Pink; R = Red; V = Violet/Purple; W = Brown; Y = Yellow. For example, catalog code DS03R would include red dyed microspheres with diameters from 0.5 to 0.99 µm.

		Material Safety Data Sheets Polystyrene Dyed

Polystyrene Dyed and Other Polymers Dyed
Polystyrene, styrene/divinylbenzene copolymer, polymethylmethacrylate, polyvinyltoluene, and various other polymers & copolymers: (hydrophobic microspheres, with sulfate surface groups): PS and S/DVB are the most common, but the other polymers offer different densities, glass transition temperatures (softening points), and refractive indices, where these properties are important. Ask for the colors and properties which you need.

Polystyrene Carboxyl Dyed
Styrene/acrylic acid copolymers are most common, but we have two other types of COOH-modified microspheres and any of these can be dyed. (See Polystyrene Carboxyl, above, for more details.) Our current products are typical of what we can do, but not all that we can do. What do you need? Download TechNote #205 for covalent coupling tips.

PolyLink Protein Coupling Kit
Interested in a protein coupling kit to use with your carboxyl-modified polymer or magnetic particles? PolyLink is your answer!

We understand many different applications, like flow cytometry, and we have microspheres specially prepared for these applications. Overall, we have >40 different sized microspheres colored with >10 different dyes of various excitation and emission wavelengths. The Fluorescent Dye Spectra webpage supplies the spectra of our nine standard fluorophores. And, TechNote 103 contains additional fluorescent spectra. Note that confocal microscopy point-spread function standards are specially packaged; TechNote 106 describes the confocal microscopy standards. Please ask if the size and/or color you need is not listed, as we may be able to custom make it for you.

In the "product description" field of the detailed list under each catalog code, fluorescent excitation and emission maxima are noted. For example, (502, 513) excites maximally at 502nm and has its greatest emission at 513nm. The color listed is the visual color of the microsphere suspension.

		Material Safety Data Sheets Polystyrene Dyed

Dragon Green Intensity Standard
The Dragon Green Intensity Standard kit consists of five populations of ~8µm microspheres dyed with increasing amounts of our Dragon Green fluorophore. The different intensity populations may serve as relative intensity standards for applications in fluorescence microscopy, and, as internally-dyed beads, they will stand up to the rigors of imaging. Dragon Green is an excellent spectral surrogate for fluorescein, and is suitable for use with fluorescein filter sets. The beads may also serve as very bright relative intensity or linearity standards for flow cytometry; ask about our QuickCal® Linearity Template if this is your interest.

Polystyrene Fluorescent and Other Polymers Fluorescent
We offer Polystyrene Plain, Polystyrene/DVB, and Other Polymer microspheres with a variety of fluorescent dyes.

Polystyrene Carboxyl Fluorescent
We offer carboxyl functionalized microspheres (COOH/1) with a variety of fluorescent dyes. Download TechNote #205 for covalent coupling tips.

PolyLink Protein Coupling Kit
Interested in a protein coupling kit to use with your carboxyl-modified polymer or magnetic particles? PolyLink is your answer!

Fluorescent Superparamagnetic Microspheres
To view available fluorescent superparamagnetic microspheres, please scroll down to the next section for:

• COMPEL™: Fluorescent
• MC: Fluorescent
  
• ME: Fluorescent

SNARe™ DNA Purification Systems offer rapid, cost-effective methods for isolating DNA using DNA Separation Particles. DNA Separation Particles are a suspension of superparamagnetic iron oxide particles that bind double-stranded DNA. Once bound, the DNA-particle complex is stable and can be washed to remove any impurities or unwanted proteins from the sample to provide a clean DNA preparation.

SNARe™ (Simple Nucleic Acid Recovery) products are based on a new patent pending technology.

Truly superparamagnetic, they respond to a magnet but display negligible residual magnetism. The surface groups are intended for covalent coupling of ligands (proteins, DNA, etc.). For details about these beads, like applications, handling, and storage, see TechNote #102; for covalent coupling protocols, see TechNote #205. Protein coated magnetic particles are available under our ProActive® Microsphere section.

		Material Safety Data Sheets Superparamagnetic ProMag™

ProMag™ 1k resolution

COMPEL™ Uniform Magnetic Microspheres
Our highly uniform superparamagnetic microspheres are ideal for applications that demand uniform bead response such as miniaturized bioassays and separations. Composed of magnetite dispersed in a polymer matrix, COMPEL™ particles are then overcoated with functional polymer for encapsulation of magnetite and introduction of reactive groups. Our initial offerings include 3µm, 6µm and 8µm beads with measured CVs of ≤ 5% and high levels of COOH-functionalization. Customers ordering our 0.25mL offering will also receive a 1.5mL magnetic separator - absolutely free!

COMPEL™: Fluorescent

** Call about our special introductory offer. **

PolyLink Protein Coupling Kit
Interested in a protein coupling kit to use with your carboxyl-modified polymer or magnetic particles? PolyLink is your answer!

Classical Magnetic Microspheres
Various types of ~1 µm diameter carboxyl-modified microspheres contain ~20-60% magnetite and are made by a special process whereby a ferrofluid (magnetite)/styrene/divinylbenzene mixture is dispersed in water, and suspension-polymerized to trap the magnetite in the polymer matrix. The magnetite is dispersed throughout the beads.

MC: Fluorescent

Encapsulated Magnetic Microspheres
Like the Classical Magnetic Microspheres above, but with an added outer shell of pure polymer. These microspheres have a magnetite-rich core + polymer shell, with carboxyl surface groups. They make better solid supports for applications using enzymes---there is no iron on the surface!

ME: Fluorescent

BioMag Superparamagnetic Particles are utilized in the magnetic separation of cells, organelles, proteins, immunoglobulins, nucleic acids, and many other types of molecules in biological and non-biological systems. BioMag are irregularly shaped iron oxide particles. The irregular shape affords a much greater surface area than that of the same size spherical particle. This large surface area results in high binding capacities, allowing efficient target capture with minimum amounts of particles. BioMag particles are greater than 90% iron oxide resulting in a fast magnetic separation, especially on high throughput automated platforms. The particles are covered with a coating that provides functional groups for the attachment of proteins or antibodies.

There are three varieties of BioMag Superparamagentic Microparticles: BioMag®, BioMag®Plus, and BioMag® Maxi. BioMag particles have a mean diameter of ~1.5µm (with the exception of BioMag Superparamagnetic Iron Oxide [~10µm]). BioMagPlus particles are similar to conventional BioMag particles with the important distinctions of fewer fines and BioMagPlus particles are offered in kits as the principle component. BioMag Maxi particles have a mean diameter of ~3-12µm.

	Catalog Code	Product Description	Particle Concentration	Volume	Price Schedule
BioMag®
BioMag® Superparamagnetic Iron Oxide
ORDER	BM547	BioMag Superparamagnetic Iron Oxide (~10µm)	50mg/mL	10mL	A9
BioMag® Unconjugated Particles
ORDER	BM546	BioMag Amine	50mg/mL	10mL	A3
				100mL	A3
ORDER	BM570	BioMag Carboxyl	20mg/mL	10mL	A7
				100mL	A7
BioMag® Magnetic Immobilization Kit
ORDER	BM545	BioMag Magnetic Immobilization Kit	50mg/mL	1 Kit	K5
BioMag® Binding Proteins
ORDER	BM552	BioMag Biotin	5mg/mL	5mL	B7
ORDER	BM554	BioMag Protein A	5mg/mL	10mL	D4
ORDER	BM553	BioMag Protein G	5mg/mL	10mL	D4
ORDER	BM551	BioMag Streptavidin	5mg/mL	5mL	B2
				50mL	B2
ORDER	BM568	BioMag Streptavidin, Nuclease-free	1mg/mL	10mL	A1
				25mL	A1
				10mL	M6
BioMag® Secondary Antibody Particles
ORDER	BM563	BioMag anti-Human IgG	1mg/mL	50mL	C3
ORDER	BM562	BioMag anti-Human IgG (Fc)	5mg/mL	50mL	C5
ORDER	BM561	BioMag anti-Human IgM	1mg/mL	50mL	C8
ORDER	BM549	BioMag anti-Mouse IgG	1mg/mL	50mL	A5
				500mL	A5
ORDER	BM550	BioMag anti-Mouse IgG (Fc)	5mg/mL	50mL	B6
				500mL	B6
ORDER	BM558	BioMag anti-Mouse IgM	1mg/mL	50mL	A6
				500mL	A6
ORDER	BM559	BioMag anti-Rabbit IgG	1mg/mL	50mL	A6
				500mL	A6
ORDER	BM560	BioMag anti-Rat IgG	1mg/mL	50mL	A5
				500mL	A5
ORDER	BM548	BioMag anti-Rat IgG (Fc)	5mg/mL	50mL	C2
				500mL	C2
ORDER	BM557	BioMag anti-Rat IgM	5mg/mL	50mL	C6
				500mL	C6
BioMag® Nucleic Acid Kits and Particles
ORDER	BM569	BioMag mRNA Purification System	5mg/mL	1 Kit	K3
ORDER	BM529	BioMag Oligo (dT)20, Nuclease-free	5mg/mL	2mL	A2
BioMag® anti-Human Leukocyte Particles
ORDER	BM595	BioMag anti-Human CD2	4mg/mL	5mL	D5
ORDER	BM580	BioMag anti-Human CD3	4mg/mL	5mL	D5
ORDER	BM581	BioMag anti-Human CD4	1.5mg/mL	5mL	C1
ORDER	BM583	BioMag anti-Human CD8	1.5mg/mL	5mL	C1
ORDER	BM596	BioMag anti-Human CD11b	1mg/mL	5mL	A4
ORDER	BM584	BioMag anti-Human CD14	1.5mg/mL	5mL	D5
ORDER	BM585	BioMag anti-Human CD16	4mg/mL	5mL	C9
ORDER	BM586	BioMag anti-Human CD19	4mg/mL	5mL	D3
ORDER	BM587	BioMag anti-Human CD34	4mg/mL	5mL	D7
ORDER	BM588	BioMag anti-Human CD45	4mg/mL	5mL	C4
ORDER	BM589	BioMag anti-Human CD56	4mg/mL	5mL	C7
ORDER	BM590	BioMag anti-Human CD71	4mg/mL	5mL	D1
BioMag® anti-Mouse Leukocyte Antibody Particles
ORDER	BM592	BioMag anti-Mouse CD4	1mg/mL	5mL	A8
ORDER	BM593	BioMag anti-Mouse CD8a	1mg/mL	5mL	A8
ORDER	BM594	BioMag anti-Mouse CD45R	1mg/mL	5mL	A8
BioMag® T cell Enrichment Systems
ORDER	BM597	BioMag Human CD3+ T cell Enrichment System	1mg/mL	1mL	B1
				5mL	B1
ORDER	BM598	BioMag Human CD4+ T cell Enrichment System	1mg/mL	1mL	B1
				5mL	B1
ORDER	BM599	BioMag Human CD8+ T cell Enrichment System	1mg/mL	1mL	B1
				5mL	B1
BioMag® Dextran-coated Charcoal (1-10µm in size)
ORDER	BM555	BioMag Dextran-coated Charcoal	5mg/mL	100mL	B8
ORDER	BM556	BioMag Dextran-coated Charcoal Concentrate	>40mg/mL	1000mL	D6
BioMag®Plus
ORDER	BP610	BioMagPlus Amine Protein Coupling Kit	50mg/mL	1 Kit	K4
ORDER	BP617	BioMagPlus Amine	50mg/mL	10mL	B3
ORDER	BP611	BioMagPlus Carboxyl Protein Coupling Kit	20mg/mL	1 Kit	K4
ORDER	BP618	BioMagPlus Carboxyl	20mg/mL	10mL	B3
ORDER	BP612	BioMagPlus anti-Mouse IgG Antibody Coupling Kit	1mg/mL	1 Kit	K4
ORDER	BP619	BioMagPlus anti-Mouse IgG	1mg/mL	50mL	B5
ORDER	BP614	BioMagPlus Protein A Antibody Isolation Kit	5mg/mL	1 Kit	K4
ORDER	BP620	BioMagPlus Protein A	5mg/mL	10mL	D8
ORDER	BP626	BioMagPlus Protein G Antibody Isolation Kit	5mg/mL	1 Kit	K4
ORDER	BP627	BioMagPlus Protein G	5mg/mL	10mL	D8
ORDER	BP621	BioMagPlus Streptavidin / Biotin Binding Kit	5mg/mL	1 Kit	K4
ORDER	BP628	BioMagPlus Streptavidin	5mg/mL	10mL	D2
ORDER	BP531	BioMagPlus Concanavalin A	50mg/mL	3mL	M6
				10mL	M6
ORDER	BP530	BioMagPlus Wheat Germ Agglutinin	50mg/mL	3mL	M6
ORDER	BP622	BioMagPlus Mouse anti-Fluorescein IgG	1mg/mL	50mL	D9
ORDER	BP658	BioMag ProMax Albumin Removal Kit	25 Reactions	1 Kit	K6
ORDER	BP659	BioMag ProMax Serum IgG Removal Kit	10 Reactions	1 Kit	K6
BioMag® Maxi
ORDER	BMM30	BioMag Maxi Carboxyl	20mg/mL	10mL	E1
ORDER	BMM40	BioMag Maxi Amine	50mg/mL	10mL	E1

Our magnetic separators are designed to accommodate a complete range of magnetic separation applications, including cell sorting, mRNA and DNA isolation, and purification of biomolecules. For investigational use only.

Magnetic Separators

We have developed special unique coating techniques which offer maximum ligand-binding capacity with excellent stability (shelf life). Data is available for binding of all appropriate ligands (small to large). Ask for sample certificates of analysis. TechNote #101 provides an overview of current products, sample applications, and procedures for using all of our ProActive® microspheres.

ProActive® Microspheres
Sold as 1% w/v aqueous suspensions (1 mL contains 10 mg of coated microspheres), the coatings are applied to our magnetic, polymeric, dyed, and silica microspheres. Just click on the appropriate catalog code for the latest list of available bead/coating combinations. Or ask us for the coating you need on the microsphere of your choice. Streptavidin binds biotinylated ligands easily and with great affinity, while Protein A picks up and orients IgGs from many species. Our anti-Mouse coating binds all subclasses of mouse IgGs.

Both Streptavidin and SuperAvidin™ are biotin binding proteins. At this time, our standard product is streptavidin coated microspheres. SuperAvidin™ coated microspheres are research products. SuperAvidin™ is a proprietary molecule that has been found to outperform streptavidin in certain applications, in terms of higher binding of biotinylated ligands and lower non-specific binding.

		Material Safety Data Sheets Biotin Anti-Mouse IgG Protein A Streptavidin Superavidin™

Catalog Code		Bead Type/Coating
CM01N		Magnetic/Streptavidin
CM02N		Magnetic/Protein A
CM03N		Magnetic/Secondary Antibody
CM01F		Magnetic/Streptavidin/Fluorescent
CM02F		Magnetic/Protein A/Fluorescent
CM03F		Magnetic/Secondary Antibody/Fluorescent
CP01N		Polymeric/Streptavidin
CP02N		Polymeric/Protein A
CP03N		Polymeric/Secondary Antibody
CP10N		Polymeric/Other
CP01*		Dyed Polymer/Streptavidin
CP02*		Dyed Polymer/Protein A
CP03*		Dyed Polymer/Secondary Antibody
CP10*		Dyed Polymer/Other
CS01N		Silica/Streptavidin
* refer to color chart above

Our non-porous beads are useful in molecular biology and immunoassays. (Download TechNote #104) Diameters are 0.3-5 µm, density 1.96 g/cm³, refractive index (589nm) 1.43-1.46; and they have high temperature stability (to 1000°C). These have been used to adsorb DNA, RNA and oligonucoeotides to recover them from cell lysates. They can be used for capillary electrochromatography (CEC).

		Material Safety Data Sheets Silica Plain Silica Carboxyl Silica Amine

Silica Plain (Hydrophilic)
SiO₂ with natural hydroxyl or silanol (Si-OH) surface groups- for adsorption of nucleotides with low protein binding.

Silica Carboxyl
SiO₂ with carboxyl (COOH) surface groups for the covalent attachment of biomolecule. Available dry, in three standard mean diameters: ~0.5µm, ~1.0µm, and ~5.0µm.

Silica Amine
SiO₂ with amine (NH₂) surface groups for the covalent attachment of biomolecule. Available dry, in three standard mean diameters: ~0.5µm, ~1.0µm, and ~5.0µm.

Silica Streptavidin: click here for our current product listing
SiO₂ with streptavidin surface groups for the affinity attachment of biomolecule. Available in three standard mean diameters: ~0.5µm, ~1.0µm, and ~5.0µm.

Available in 38 nominal mean diameters ranging from 40nm to 175µm, our highly characterized polymer size standards are suitable for validation of sizing instruments across their dynamic ranges. Additional features and benefits include a Certificate of Traceability, convenient and economical packaging, ease of use, and highly competitive pricing.

NIST Certificate / Product Data Sheet

		Material Safety Data Sheets NIST Traceable Particle Size Standards

Click here for our current listing: NIST Traceable Particle Size Standards

Trypan blue exclusion is a common method for the determination of cell viability. It is used extensively in cell and tissue culture programs, and for a range of research studies including apoptosis, cytopathic effects of viral infection, and effects of sample processing methods on cell viability and concentration.

Instrumental methods for cell viability analysis provide significant advantages over manual determinations, offering high accuracy, precision and throughput. However, as with any analytical instrument, it is important to implement a QC program to ensure confidence in results.

Our new ViaCheck™ Viability Instrument Standards are the latest addition to our extensive line of microsphere standards for instrument QC. ViaCheck standards mimic the light scattering characteristics of live and dead cells in the trypan blue dye exclusion method, and may be used to confirm the capabilities and verify the performance of image-based cell viability instruments. The standards are available in a range of common concentrations and live / dead ratios.

		Material Safety Data Sheets 0% Viability Control 50% Viability Control 75% Viability Control 90% Viability Control 100% Viability Control Concentration Control (1 x 106) Concentration Control (4 x 106) Concentration Control (8 x 106)