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Temperature-Switchable Agglomeration of Magnetic Particles Designed for Continuous Separation Processes in Biotechnology
journal contribution
posted on 2015-07-08, 00:00 authored by Anja S. Paulus, Raphael Heinzler, Huey Wen Ooi, Matthias FranzrebThe
purpose of this work was the synthesis and characterization
of thermally switchable magnetic particles for use in biotechnological
applications such as protein purification and enzymatic conversions.
Reversible addition–fragmentation chain-transfer polymerization
was employed to synthesize poly(N-isopropylacrylamide)
brushes via a “graft-from” approach on the surface of
magnetic microparticles. The resulting particles were characterized
by infrared spectroscopy and thermogravimetric analysis and their
temperature-dependent agglomeration behavior was assessed. The influence
of several factors on particle agglomeration (pH, temperature, salt
type, and particle concentration) was evaluated. The results showed
that a low pH value (pH 3–4), a kosmotropic salt (ammonium
sulfate), and a high particle concentration (4 g/L) resulted in improved
agglomeration at elevated temperature (40 °C). Recycling of particles
and reversibility of the temperature-switchable
agglomeration were successfully demonstrated for ten heating–cooling
cycles. Additionally, enhanced magnetic separation was observed for
the modified particles. Ionic monomers were integrated into the polymer
chain to create end-group functionalized particles as well as two-
and three-block copolymer particles for protein binding. The adsorption
of lactoferrin, bovine serum albumin, and lysozyme to these ion exchange
particles was evaluated and showed a binding capacity of up to 135
mg/g. The dual-responsive particles combined magnetic and thermoresponsive
properties for switchable agglomeration, easy separability, and efficient
protein adsorption.
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thermogravimetric analysisbiotechnological applicationsContinuous Separation ProcessespH valueparticle agglomerationprotein bindingsalt typeBiotechnologyThe purposeMagnetic Particlesprotein purificationswitchable agglomerationparticle concentrationion exchange particlesIonic monomersbinding capacitythermoresponsive propertiespolymer chainkosmotropic saltprotein adsorptionserum albumin
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