Microspheres offer a highly convenient and flexible system for test and assay reagent development. Many different types of spheres are available to address the diverse and evolving needs of research and commercial aims – polymer, silica, and magnetic, with different surface chemistries in a range of sizes. Beads offer a large specific surface area for binding, permit efficient capture and isolation of target, and they are highly amenable to automation and miniaturization. See our TechNote on Microsphere Selection for tips on choosing beads for different test and assay formats. Please check out our Microsphere Reagent Development Guide, an overview of products that we manufacture for IVD test / assay development, and considerations for products selection and handling,

Test / Assay Format Bead Size Bead Type Coating Strategy Detection
Turbidimetric 50nm – 500nm Undyed- (plain, COOH) Covalent Turbidimetry TN304
Magnetic Chemiluminescence 1 - 5 µm ProMag® HP Covalent Luminescence PDS 743
Flow cytometric 2µm – 15µm QuantumPlex™  QuantumPlex™M Covalent or streptavidin / biotin Flow cytometer PDS 250, PDS 235
Bead “ELISA” 1- 3 µm ProMag®, ProMag® HP Covalent Spectrophotometer TN301
Lateral Flow 0.1µm – 0.4µm Dyed, Europium Chelate Covalent or adsorption Visual or Automated Reader TN303
Lateral Flow – Boulders in the Stream 0.1µm – 0.4µm mobile phase, ~2µm – 3µm capture phase Dyed (visible) mobile phase, Undyed capture beads- (plain, COOH) Covalent or adsorption Visual TN303
Dipstick 0.1µm – 0.4µm Dyed (visible) Covalent or adsorption Visual TN303
Latex Agglutination Test (LAT) 0.2µm – 1.0µm Undyed- (plain, COOH) or visibly dyed Covalent or adsorption Visual TN301, TN303

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