Facile one-pot assembly of adhesive phenol/FeIII/PEI complexes for preparing magnetic hybrid microcapsules

Abstract

Magnetic organic–inorganic hybrid microcapsules consisting of plant phenols, polyethylenimine (PEI) and Fe^III ion complexes were prepared in a facile one-pot way. Porous CaCO₃ microparticles were used as the hard template for the adsorption of negatively charged Fe₃O₄ nanoparticles, which acted as the source of magnetism for recycling. Moreover, the coated Fe₃O₄ nanoparticles also helped to improve the rigidness of the microcapsules away from rupturing during multiple reuses. Upon addition of tannic acid (TA), PEI and Fe^III ions, the magnetic CaCO₃ microparticles were coated with the adhesive complexes through chemical chelation and covalent bonding. Then the template was removed using EDTA to construct the target microcapsules. During the CaCO₃ formation step, Candida rugosa lipase (CRL) was used as the biomolecule which was encapsulated in the CaCO₃ microparticles. Characterizations demonstrated that the as-prepared magnetic microcapsules showed a robust structure, so that the enzyme inside could be protected physically. As a result, the magnetic hybrid microcapsules exhibited high efficiency in enzyme catalysis and stability against the environment, due to the high biocompatibility and robust structure.