title: Preparation of Fe3O4@SiO2@layered double hydroxide core-shell microspheres for magnetic separation of proteins.
abstract: Three-component microspheres containing an SiO(2)-coated Fe(3)O(4) magnetite core and a layered double hydroxide (LDH) nanoplatelet shell have been synthesized via an in situ growth method. The resulting Fe(3)O(4)@SiO(2)@NiAl-LDH microspheres display three-dimensional core-shell architecture with flowerlike morphology, large surface area (83 m(2)/g), and uniform mesochannels (4.3 nm). The Ni(2+) cations in the NiAl-LDH shell provide docking sites for histidine and the materials exhibit excellent performance in the separation of a histidine (His)-tagged green fluorescent protein, with a binding capacity as high as 239 μg/mg. The microspheres show highly selective adsorption of the His-tagged protein from Escherichia coli lysate, demonstrating their practical applicability. Moreover, the microspheres possess superparamagnetism and high saturation magnetization (36.8 emu/g), which allows them to be easily separated from solution by means of an external magnetic field and subsequently reused. The high stability and selectivity of the Fe(3)O(4)@SiO(2)@NiAl-LDH microspheres for the His-tagged protein were retained over several separation cycles. Therefore, this work provides a promising approach for the design and synthesis of multifunctional LDH microspheres, which can be used for the practical purification of recombinant proteins, as well as having other potential applications in a variety of biomedical fields including drug delivery and biosensors.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
authors.forename: Mingfei
authors.initials: M
authors.lastname: Shao
authors.forename: Fanyu
authors.initials: F
authors.lastname: Ning
authors.forename: Jingwen
authors.initials: J
authors.lastname: Zhao
authors.forename: Min
authors.initials: M
authors.lastname: Wei
authors.forename: David G
authors.initials: DG
authors.lastname: Evans
authors.forename: Xue
authors.initials: X
authors.lastname: Duan
mesh_terms: D052203:Ferrosoferric Oxide / Q000737:chemistry*; D060526:Magnetic Fields; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008863:Microspheres; D011506:Proteins / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D011506:Proteins; D012822:Silicon Dioxide; D052203:Ferrosoferric Oxide