New Immunoassay Bead Expands IVD Offering

A new immunoassay bead has been developed for in vitro diagnostic (IVD) applications. The immunoassay provides highly precise immobilization of small antigens such as peptides, steroids, and hormones to the surface of the beads.

The beads include a controlled number of carboxylic acid groups. The antigen of choice can then be coupled to the beads, either directly or via a linker, using carbodiimide- mediated amide bond formation. This reduces the need for bovine serum albumin (BSA) blocking, which is often used to avoid non-specific binding of serum proteins that would otherwise interfere with the assay.

The superparamagnetic beads, called Dynabeads, exhibit magnetic properties when placed within a magnetic field and show no residual magnetism when removed from this field. Dynabeads are a product of Dynal, a company that now belongs to Invitrogen (Grand Island, NY, USA). The true spherical shape and defined surface chemistry of the beads minimize chemical agglutination and non-specific binding. The specific characteristics of the many available bead types facilitate magnetic separation of a wide variety of targets. Separation is gentle and no column or centrifugations are necessary.

The new Dynabeads MyOne immunoassay provides an excellent solid support for antigen-down immunoassays. The hydrophilic surface ensures low non-specific binding, excellent dispersion abilities, and easy handling in a wide variety of buffers. The beads also have a high magnetic mobility in combination with a low sedimentation rate, making them ideal for automated assays. Furthermore, Dynabeads do not inhibit enzymatic activity and can be included directly in downstream analysis of the bead-bound target molecule. Alternatively, the target molecule can be eluted off the Dynabeads using conventional elution methods.

Hege Skjellerudsveen, Dynal IVD product manager said, "The new low charge carboxyl immunoassay bead, expands our excellent IVD bead offering. It is particularly suited to infectious disease testing, along with other antibody tests (autoimmune, allergy, small molecule hormones, and drugs). It gives customers the opportunity to develop antigen-based assays more easily, as well as with much higher consistency and sensitivity compared to alternative techniques.”



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