Dyed Estapor® Microspheres

The Estapor® product offering includes colored microspheres. These microspheres are also extremely uniform and are dyed internally so that their surface properties are unchanged, thereby ensuring maximum color brilliance and preventing dye leaching in water or aqueous buffers.

We offer more than 100 dyed microspheres (red, blue, green, black, yellow…), an effect known as the Rainbow Effect. Incorporating colored dye into our uniform microspheres greatly enhances their interest and utility in some tests and opens up new frontiers for applications in the diagnostics, life sciences, biotechnology, electronics or environment fields.

Custom Development of Dyed Microspheres

If you are looking for dyed microspheres not available from our standard menu, Estapor® Microspheres can provide custom development for the diagnostic, biotech, and pharmaceutical industries. Our experience in dyed microsphere(s) development allows our technical department to quickly and inexpensively produce custom microspheres to fit your very specific requirements. Please send your detailed custom requirements to your Estapor® representative. You don't have to search any further for a potential source of dyed microspheres.

Unfunctionalized Dyed Estapor® Microspheres

Plain microspheres do not have any functional groups on their surfaces. These microspheres are dedicated to hydrophobic or passive immobilization of biomolecules onto their surface, a coupling passive procedure that works perfectly well for biomolecules with a molecular weight of 10 kDa and more.

For biomolecules with a molecular weight under 10 kDa, we recommend a covalent coupling procedure.

Functionalized Dyed Estapor® Microspheres

Highly polar or ionizable chemical groups increase the colloidal stability of the microsphere's suspension and allows covalent binding of polyclonal or monoclonal antibodies, proteins and haptens.

In comparison to physical adsorption, covalent binding of antigens or antibodies to polymer microspheres improves the test performance, and the reagents produced are more stable over time.

Moreover, microspheres with specific functional groups on their surface can bind proteins covalently in the appropriate orientation, directly or by additional activation, giving more sensitive and specific immunoreagents. Some of the surface groups able to covalently bound directly amino acid protein residues are chloromethyl; or after preactivation with carboxy, amino or hydroxy groups.

Due to their more hydrophilic surface, our functionalized polymer microspheres have very low non-specific-binding, and a better signal-to-noise ratio.

• Carboxyl-modified Red Dyed microspheres (–COOH)
  Highly polar or ionisable chemical groups increase latex stability, and also facilitate covalent coupling of proteins to the microsphere surface.
  
  The groups –COOH are produced by copolymerisation of the corresponding functional monomers. For carboxylated latexes, eliminating surfactant and lowering of the pH decreases latex stability and may trigger partial flocculation. In this case, we recommend diluting the latex further and slowing the stirring. If the result is still unsatisfactory, a non-ionic emulsifier may be added. (0.1 to 0.5 g/L of TWEEN 20).
  
  
• Hydroxy-modified Red Estapor® Microspheres
  Highly polar or ionisable chemical groups increase latex stability and also facilitate covalent coupling of proteins to the microsphere surface.
  
  The groups –OH are produced by copolymerisation of the corresponding functional monomers.
  
  
• Chloromethyl-modified Red Estapor® Microspheres (–CH2Cl)
  Highly polar or ionisable chemical groups increase latex stability and also facilitate covalent coupling of proteins to the microsphere surface.
  
  The groups –CH2Cl are produced by copolymerisation of the corresponding functional monomers.