Dynabeads

Dynabeads are superparamagnetic spherical polymer particles of uniform size, with a consistent, defined surface for the adsorption or coupling of bioreactive molecules or cells. They were developed after John Ugelstad managed in 1976, at the University of Trondheim in Norway, to create uniform polystyrene spherical beads of exactly the same size, something otherwise achieved only by NASA in the weightless conditions of Skylab. Dynabeads are typically 1 to 5 micrometers in diameter, which sets them apart from magnetic-activated cell sorting beads of about 50 nanometers. The technology was licensed to Dynal in 1980 and, after a series of mergers and acquisitions, Dynabeads are now owned and produced by Invitrogen, part of Thermo Fisher Scientific. They have revolutionised the liquid-phase kinetic separation of biological materials and are frequently used to isolate cells such as CD4+ T cells, stem cells and circulating tumor cells.