Facile preparation of magnetically functionalized graphite nanosheets for porcine pancreatic lipase immobilization

The graphite nanosheets decorated with Fe3O4 nanoparticles (about 15–20 nm), i.e., Fe3O4@graphite nanosheets, have been prepared via a facile one-pot method. The resulting composites with large specific surface area, high affinity, and rapid magnetic response were characterized by means of Fourier transform infrared spectra, Raman spectra, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, elemental analysis, and thermogravimetric analysis, which indicated that the Fe3O4 nanoparticles were chemically integrated on the graphite nanosheets. The porcine pancreatic lipase (PPL) was immobilized onto the Fe3O4@graphite nanosheets through covalent bonding using glutaraldehyde as a coupling reagent, and the properties of the resulting immobilized PPL such as enzymatic activity, stability, and reusability were researched at the same time. The result proved that the immobilized PPL displayed excellent properties and demonstrated that the prepared Fe3O4@graphite nanosheets would present a potential application as a novel carrier for enzyme immobilization, enrichment, and separation.