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White Estapor® Microspheres


Estapor® Microspheres
for Latex Turbidimetry Immunoassay and Agglutination (LTIA)

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IT 250 microspheres are highly uniform in size and shape

IT 250 microspheres are highly uniform in size and shape.

Latex Turbidimetric Immunoassays and Latex Agglutination (LTIA) tests consist of particles or microspheres which are coated with antigens or antibodies that react with a specific biomarker or pathogen. Upon addition of a clinical sample, particle aggregation is triggered in the presence of the specific biomarker to create antibody/antigen – biomarker interactions that result in measurable precipitating complexes. These complexes allow for quick and easy determination of the biomarker concentration through turbidimetry or visual detection of the presence or absence of the biomarker through agglutination.
Offering a recognized and established portfolio of microspheres with proven success, our range of products are adapted to both manual and instrumentation-based platforms, are highly characterized, dimensionally uniform and exhibit exceptional lot-to-lot reproducibility.
See our full list of microsphere offerings here.

Just released

Download our new application note "Performance of Estapor® Microspheres in a Latex Turbidimetry Immunoassay for C-reactive Protein (CRP)"
Download our new brochure "Estapor® Microspheres for Latex Turbidimetry Immunoassay and Agglutination"

Plain Estapor® Microspheres for Latex Turbidimetry Immunoassay (LTIA)

Our plain Estapor® microspheres offer a simple and convenient option for LTIA diagnostics tests. The plain surface of the microsphere is designed to be easily and quickly coated with the antibody or antigen of choice via protein adsorption through hydrophobic and ionic interactions. This passive coupling procedure works particularly well for biomolecules with a molecular weight of 10 kDa or more. Our plain microspheres are available in a variety of sizes as well as surfactant-free.
See full offering of Plain Estapor® Microspheres and Plain Surfactant-free Estapor® Microspheres for LTIA here.

Surface functionalized Estapor® Microspheres for Latex Turbidimetry Immunoassay

The introduction of highly polar carboxyl groups to the surface of the microsphere allows covalent binding of antibodies and other proteins. The resulting conjugation is extremely stable over time and due to their hydrophilic surface, our functionalized microspheres exhibit low non-specific binding and an enhanced signal-to-noise ratio.
For biomolecules with a molecular weight under 10 kDa, we recommend a covalent coupling procedure. We offer a wide variety of functionalized microspheres, with different sizes, carboxyl content and polymer offerings available. Microsphere selection will depend on the desired analytical performance and the optical requirements of a particular assay. Our dedicated team of technical specialists are on hand to offer guidance.

Small Carboxyl-Modified Estapor® Microspheres for LTIA

These smaller microspheres and their slower agglutination kinetics within LTIA tests are designed to help mitigate against the ‘hook’ or ‘prozone’ effect whereby the effectiveness of antibodies to form immune complexes can be diminished when concentrations of the biomarker of interest are high.
See full offering here.

New IT 250 Carboxyl-Modified Estapor® Microspheres for LTIA

Our new IT 250 microspheres have been designed with key features for Latex Turbidimetry Immunoassays (LTIA). Combining both a larger size and surface functionalization these microspheres are particularly well suited to LTIA tests where high sensitivity is required. Our IT 250 microspheres are extremely uniform in size and shape and exhibit excellent lot-to-lot consistency.
Find out more here.

Product NameDiameter (µm)Surface COOH (µeg/g)PolymerCatalogue Number
IT 250 0.220 -0.275 45 - 85 Polystyrene 80380626

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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.

Estapor® Microspheres for Latex Agglutination

Latex agglutination (Latex ID) testing is often used to detect microbial pathogens in various samples like human fluids, food and plate culture. The visual evaluation of latex agglutination necessitates different microsphere features. Our latex agglutination range of larger microspheres is perfectly suited to this application. Both plain and surface functionalized options are available, with all microspheres exhibiting high size and shape uniformity and excellent lot-to-lot reproducibility.
See full offering here.

Latex agglutination on a slide using Estapor<sup>®</sup> K 080 microspheres, left (+), right (-).

Fig. 2 Latex agglutination on a slide using Estapor® K 080 microspheres, left (+), right (-).

Schematic of the Excitation and Emission profile of 'XC'

Fig. 3 TEM of Estapor® K 080 microspheres showing consistent size and shape.

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