3-D magnetic graphene oxide-magnetite poly(vinyl alcohol) nanocomposite substrates for immobilizing enzyme

• Published in: Polymer (Guilford) 2018-08, Vol.149, p.13-22
• Main Authors: Li, Yanyun, Jing, Tao, Xu, Gaofeng, Tian, Jingzhi, Dong, Mengyao, Shao, Qian, Wang, Bin, Wang, Zhikang, Zheng, Yongjie, Yang, Changlong, Guo, Zhanhu
• Format: Article
• Language: English
• Subjects: 3D-graphene oxide; Adsorption; Alcohols; Crystal structure; Enzyme; Enzymes; Fourier transforms; Graphene; Immobilization; Infrared spectroscopy; Iron oxides; Lipase; Magnetic; Magnetic properties; Magnetic saturation; Magnetite; Morphology; Nanocomposites; Organic chemistry; Pancreas; Polyvinyl alcohol; Pore size; Porosity; Scanning electron microscopy; Specific surface; Stability of enzyme activity; Stability tests; Substrates; X ray photoelectron spectroscopy; X ray powder diffraction; X-ray diffraction
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2018.06.046

Three-dimensional magnetic graphene oxide-magnetite polyvinyl alcohol (3D-GO/PVA/Fe3O4) nanocomposites were successfully prepared. The morphology was characterized and analyzed through scanning electron microscope (SEM) and transmission electron microscope (TEM). The chemical structure and the crystal structure were explored by X-ray powder diffraction (XPS), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction spectra (XRD). The magnetic property was obtained by vibrating sample magnetometer (VSM). The specific surface area and the average pore size were determined by Brunauer-Emmett-Teller (BET) and Barrett–Joyner–Halenda (BJH). The specific surface and the average pore size of 3D-GO/PVA/Fe3O4 nanocomposites were 388.87 m2g-1 and 9.6 nm, and the higher specific surface indicated that the three-dimensional structure avoided the aggregation for GO sheets. The large saturation magnetization (Ms) of the nanocomposites of 30.5 emu/g enabled the easy cycling of the nanocomposites. The 3D-GO/PVA/Fe3O4 nanocomposites exhibited better performance for porcine pancreatic lipase (PPL) enzyme immobilization. The maximum immobilization efficiency was 91%, and the enzyme immobilized 3D-GO/PVA/Fe3O4 nanocomposites reached up to 90% of their activities. After 10 cycles of reuse, the activity of immobilized enzyme remained about 70.8% of the initial activity. The stability test revealed that the activity of immobilized enzyme remained up to 71.1% at 4 °C for 56 days. [Display omitted] •Three-dimensional network structure prevented GO from agglomeration.•Hydroxyl-rich PVA provided more binding sites for immobilizing enzyme.•The best immobilized efficiency for (3D-GO/PVA/Fe3O4)-PPL (91%) was much higher than that for (GO/Fe3O4)-PPL (76%).•The immobilized enzyme exhibited high stability.