White Estapor® Microspheres

White Estapor® Microspheres

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The standard Estapor® microspheres are uniform in size and homogeneous in shape with an excellent lot–to–lot reproducibility. Red blood cells are used in Indirect Hemaglutination tests (IHA) but with some technical limitations. The Dyed Estapor® Microspheres could easily replace the classical red blood cells to offer a quicker and easier test to perform. In fact, Dyed Estapor® Microspheres allow a better traceability and stability, a higher reproducibility, and improved safety (the red blood cells could be contaminated by biological agents such as viruses, prions, bacteria, etc.).

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Unfunctionalized White Estapor® Microspheres

The plain microspheres do not have any functional groups onto their surfaces. These microspheres are dedicated to hydrophobic or passive immobilization of biomolecules onto their surface. This coupling passive procedure 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.

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Functionalized White Estapor® Microspheres

Highly polar or ionizable chemical groups increase the colloidal stability of the microspheres suspension and allow 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 white 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 pH decrease 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).

Amino–modified white microspheres (–NH2)

Highly polar or ionisable chemical groups increase latex stability and also facilitate covalent coupling of proteins to the microsphere surface. The groups –NH2 are produced by copolymerisation of the corresponding functional monomers.

Chloromethyl–modified white 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.

Hydroxy-modified White Estapor® Microspheres (–OH)

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.