Before revision: Superparamagnetic microbeads: the monosized Dynabeads (scanning electron microscope image) Microbeads, also called Ugelstad particles after the Norwegian chemist John Ugelstad, who invented and patented them in 1977 , are uniform polymer particles, typically 0.5 to 500 micrometres in diameter.
After revision: Superparamagnetic microbeads: the monosized Dynabeads (scanning electron microscope image) Microbeadsand patented the method in 1978,Rangnes 1997:4–5 also called Ugelstad particles after the Norwegian chemist John Ugelstad, who invented , professor them in 1977 , are uniform polymer particles, typically 0.5 to 500 micrometres in diameter.