Preparation of thermo-sensitive magnetic microspheres and their application to bioprocesses

Abstract

Ultrafine magnetite particles were prepared by the co-precipitation method. Poly(styrene/ N-isopropylacrylamide/methacrylic acid) latex particles containing ultrafine magnetite [magnetic P(St/NIPAM/MAA)] were prepared by two-step emulsifier-free emulsion polymerization. Most of the synthesized magnetic latex particles showed the reversible transition between flocculation and dispersion by controlling temperature, and the thermo-flocculated magnetic latex particles were separated quickly in a magnetic field. Copolymerization of divinylbenzene with St at the first step enhanced the particle growth and was effective to improve magnetic separation of thermo-flocculated latex particles. Porcine trypsin was covalently immobilized onto the thermo-sensitive magnetic latex particles with high efficiency by the carbodiimide method. The immobilized trypsin showed high activity, and hence the thermo-sensitive magnetic latex particles are effective for enzyme reaction processes.