Preparation of thermosensitive magnetic particles by dispersion polymerization
Introduction
Magnetic polymer microspheres have been applied to the studies of cell labelling, cell separation, enzyme immunoassay, target drug, etc. Because magnetic separations are relatively rapid and easy, requiring simple equipment, compared to centrifugal separation [1]. Different methods have been applied in the production of magnetic particles 2, 3.
Poly(N-isopropylacrylamide) (PNIPAM) has a lower critical solution temperature (LCST) at 32°C in water, and changes from hydrophilic below the LCST to hydrophobic above it, due to the reversible formation and cleavage of the hydrogen bonds between the amide groups and surrounding water molecules with changing temperature [4]. This reversible thermosensitivity is considered to be used in biomedical or biological field, and so on, such as purification and separation of proteins [5].
In this study, a new kind of multifunctional Fe3O4/P(St-NIPAM) particles with various diameter was prepared by different reaction conditions in the presence of magnetic fluid. In order to coat the Fe3O4 tightly by polymer, we used styrene as a comonomer. The Fe3O4/P(St-NIPAM) particles with thermosensitive and magnetic property would provide useful application, such as protein concentration, reversible release and recovery of enzymes, etc.
Section snippets
Materials
Styrene was treated with sodium hydrate solution to remove the inhibitor and stored at 4°C. NIPAM (Aldrich) was purified by recrystallization from a mixture of 1 : 1 toluene and hexane. All other materials were analytical grade, and used without further purification, including polyethylene glycol (PEG, ), potassium persulphate (KPS), hydrogen peroxide (H2O2, 30%), ethanol and ferrous sulphate.
Preparation of magnetic fluid
Fe3O4 magnetic fluid was prepared by precipitation–oxidation method as follows; 70 g of PEG was
Fe3O4 magnetic fluid
Fig. 1 shows the morphology of the Fe3O4 particles. The average diameter was about 50 nm. Most of particles were dispersed uniformly in a water solution. Some of them formed multiparticle aggregates because of the magneto-dipole interparticle interactions.
Fig. 2 shows IR spectra of the Fe3O4 magnetic fluid. Two absorption bands were observed at 1080 cm−1 and 1630 cm−1, the former bands being assigned to the C–O stretching vibration of PEG, the latter to the CO, which indicates that some of
Conclusion
Fe3O4/P(St-NIPAM) thermosensitive magnetic particles were prepared by dispersion copolymerization of St and NIPAM in the presence of Fe3O4 magnetic fluid. These particles with thermosensitive and magnetic property would provide useful application, such as protein purification, reversible release, recovery of enzymes, etc.
Acknowledgements
Project 59573011 supported by National Natural Science Foundation of China.
References (5)
- et al.
Prog. Polym. Sci.
(1992) - et al.
Biomaterials
(1990)
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