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Standard Carboxyl microspheres

Our standard carboxyl microspheres are the best choice for covalent coupling of ligands such as antibodies, antigens, proteins, peptides, and nucleic acids.

They are well suited for particle-based instrument assays such as light scattering, turbidimetric and nephelometric assays, lateral flow tests, and latex agglutination.

Over 100 products – every possible carboxyl microsphere for diagnostic assays

  • The right particle size with various levels of COOH groups

  • Optimized levels of carboxyl groups (50 to 300 µEq/g of carboxyl groups) for maximum coupling efficiency

  • Very uniform surface morphology and even distribution of functional groups

  • Highly uniform size (narrow std deviation), stability, and sensitivity

  • Batch-to-batch reproducibility, lot after lot

Carboxyl Products
Standard Carboxyl

Near-Soap-Free™ Carboxyl microspheres

PolyMicrospheres innovative process technology has led to the development of Near-Soap-Free™ carboxyl microspheres with high molecular weight.  The surface chemistry is similar to our standard carboxyl microspheres, very uniform and stable, but with very little surfactant.

  • Better than soap-free microparticles with no residual monomer and much lower amounts of sulfate groups

  • Very low surfactant levels (from 0.01% to 0.05%) and do not require clean up

  • Optimized levels of carboxyl groups and uniform surface morphology for maximum coupling efficiency

  • Novel process technology and very low surfactant level provide greater stability and uniformity


SpaceLink™ Carboxyl microspheres

SpaceLink™ carboxyl microspheres are perfect immunodiagnostic reagent particles with a spacer-linker already attached to the microspheres.  The length of the flexible spacer arm is ~10A°.  The end of the spacer arm has a carboxyl group for covalent attachment of ligands, especially for bulky ligands.

Our best product for covalent attachment of bulky ligands:

  • Almost all of the ligands coupled to the microspheres will be in an active form

  • Conformational changes of the ligands are minimized

  • Higher level of sensitivity compared to direct surface coupling

  • The flexible spacer arms improve the kinetics of agglutination reactions,
    reactivity of each coupled ligand, and greatly reduce steric hindrance problems

Steric Effect

Specialty Carboxyl microspheres with Steric Effects

Specialty carboxyl microspheres with steric effects are designed with bulky groups to eliminate passive adsorption and reduce non-specific binding.

  • Minimizes non-specific binding

  • Eliminates serum adsorption

  • Highly uniform and stable

  • Batch-to-batch reproducibility

Omni-Bind™ Lipophilic Carboxyl microspheres

Our Omni-Bind carboxyl microspheres have been developed with optimized levels of lipophilic groups to increase the coupling efficiency of various proteins.

  • Contour to the conformation of the proteins for better coupling efficiency and improved visibility of the agglutinates

  • Highly uniform and stable

  • Batch-to-batch reproducibility

Omni-Bind Lipophilic

Low-Density Carboxyl microspheres

Our low-density carboxyl microspheres are suited for applications requiring no or little settlement of the particles.

  • Optimized levels of carboxyl groups for maximum coupling efficiency

  • Designed to reduce settling

  • Minimize passive adsorption

  • Reduce non-specific binding

  • Highly uniform and stable

  • Batch-to-batch reproducibility


Hydrophilic Carboxyl microspheres

Hydrophilic carboxyl microspheres are designed with additional hydrophilic groups where stability enhancement is required to reduce aggregation problems during or after coupling of ligands.

  • Eliminates aggregation during processing and storage

  • Highly uniform and stable


Non-Polystyrene Carboxyl microspheres

Our Non-Polystyrene carboxyl microspheres are designed for applications where more hydrophilic surfaces are needed than the typical hydrophobic PS-based microspheres.

  • Lightly hydrophilic

  • Easy to centrifuge

High-Density Carboxyl microspheres

High-Density carboxyl microspheres are designed for applications where a higher density is preferred over the PS-based microspheres with density 1.05 g/cc.

  • Suitable for protein adsorption

  • Lightly hydrophilic


Soap-Free Carboxyl microspheres

Our distinctive Soap-Free carboxyl microspheres have optimum sulfate and carboxyl groups to stabilize the microparticles.

  • Optimized levels of carboxyl groups and uniform surface morphology for maximum coupling efficiency

  • No excess sulfate groups to interfere with coupling chemistry

  • No residual monomer

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