Hybrid Fluorescent-Magnetic Polymeric Particles for Biomedical Applications

Abstract

Submicron magnetic polymeric particle (MPP) and/or Janus magnetic polymeric particle (JMPP) were successfully prepared via the miniemulsion polymerization of styrene (St)/acrylic acid (AA) monomers consisting of superparamagnetic iron oxide nanoparticles (IONPs) coated with oleic acid. Since the particle nucleation occurs primarily within the monomer droplet, not only the size of particle could be controlled at the beginning but also its morphology was manipulated by using different types of initiator. The MPPs with homogeneous distribution of IONPs (41%) in P(St-DVB-AA) were obtained with using potassium persulfate (KPS) as initiator and divinyl benzene (DVB) as crosslinking agent. To obtain anisotropic JMPP, an oil-soluble initiator 2,2-azobis (2-isobutyronitrile) was used instead. The controllable phase separation between P(St-AA) and the encapsulated IONPs caused the stable spherical Janus particles containing IOPNs (15%) located on one side of polymer particle. Both MPPs and JMPPs could be easily separated by an external magnet. The MPPs were functionalized with chitosan (CS) acting as spacer and then chemical immobilized with fluorescein isothiocyanate (FITC) to produce fluorescent-MPPs. When applying as imaging device for cancer cells labeling i.e., HeLa, cells, results showed that MPPs/CS-FITC could be located inside cells with low cytotoxicity.