Fabrication and Size‐Selective Bioseparation of Magnetic Silica Nanospheres with Highly Ordered Periodic Mesostructure

Abstract

In this paper, we report a novel synthesis and selective bioseparation of the composite of Fe3O4 magnetic nanocrystals and highly ordered MCM‐41 type periodic mesoporous silica nanospheres. Monodisperse superparamagnetic Fe3O4 nanocrystals were synthesized by thermal decomposition of iron stearate in diol in an autoclave at low temperature. The synthesized nanocrystals were encapsulated in mesoporous silica nanospheres through the packing and self‐assembly of composite nanocrystal–surfactant micelles and surfactant/silica complex. Different from previous studies, the produced magnetic silica nanospheres (MSNs) possess not only uniform nanosize (90 ∼ 140 nm) but also a highly ordered mesostructure. More importantly, the pore size and the saturation magnetization values can be controlled by using different alkyltrimethylammonium bromide surfactants and changing the amount of Fe3O4 magnetic nanocrystals encapsulated, respectively. Binary adsorption and desorption of proteins cytochrome c (cyt c) and bovine serum albumin (BSA) demonstrate that MSNs are an effective and highly selective adsorbent for proteins with different molecular sizes. Small particle size, high surface area, narrow pore size distribution, and straight pores of MSNs are responsible for the high selective adsorption capacity and fast adsorption rates. High magnetization values and superparamagnetic property of MSNs provide a convenient means to remove nanoparticles from solution and make the re‐dispersion in solution quick following the withdrawal of an external magnetic field.

Functionalized Mesoporous Silica with Very Large Pores for Cellulase Immobilization

“…The C1s peak observed in the FDU-12 pure silica spectrum can most probably be attributed to residual surfactant. Figure 5 displays the solid state 13 C-CP-MAS NMR spectra of the various organo-functionalized FDU-12 samples. The three peaks in Figure 5A at the chemical shifts 8.4, 25.2, and 40.7 ppm can be attributed to the carbon atoms C 1 , C 2 , and C 3 , respectively, of the aminopropyl group that is incorporated into the silica framework (Si-O-Si-C 1 -C 2 -C 3 -NH 2 ) by cocondensation of APTES and TEOS.…”

“…13 C solid state cross-polarization magic-angle spinning nuclear magnetic resonance ( 13 C-CP-MAS NMR) measurements were performed on a Bruker MSL-300 spectrometer operating at a frequency of 75.482 MHz for 13 C. The spectrometer was equipped with a 4 mm double air bearing, magic-angle spinning probe suitable for MAS experiments. The proton 90°pulse time was 5.5 µs, the acquisition time was 45 ms, the cross-polarization time was 2 ms, and the relaxation delay was 3 s. The spectrum width was 50 kHz, and 4000 data points were collected over 2000 scans.…”

“…5 The past decade saw a large variety of mesoporous silicas being tested for their enzyme immobilization efficiency, [6][7][8][9][10][11][12] since they displayed many characteristics that may be beneficial for such a purpose, i.e., high surface area, narrow pore size distribution, tunable pore size, and high chemical and mechanical stability. [13][14][15][16] However, due to size exclusion effects occurring at the pore entries, most of these studies were limited to small proteins and enzymes. Recently, Takimoto et al studied the immobilization of cellulase on mesoporous SBA-15 materials.…”

A self-assembled polydopamine film on the surface of magnetic nanoparticles for specific capture of protein

“…Zhang et al have recently synthesized composites of Fe 3 O 4 magnetic nanocrystals and MCM-41 type periodic mesoporous silica nanospheres, and demonstrated that the mesoporous magnetic nanospheres can be used to separate cytochrome c from binary cytochrome c and bovine serum albumin solution. 15 He et al have explored two kinds of silica coated magnetic NPs as pH-dependent magnetic nanoadsorbents for the selective separation of proteins. 16 Lin et al reported synthesis of aminophenylboronic acid-functionalized magnetic iron oxide NPs for the selective capture of glycoproteins from unfractionated protein mixtures.…”

Recent advances of mesoporous materials in sample preparation

“…Therefore, a main merit of these TiO 2 membranes is their photocatalytic activity, which is able to effective declogging of these membranes when applied to separate proteins. Mesoporous silica coated carbon nanotubes [72], mesoporous polymer coated copper hydroxide nanostrands [73], magnetic silica nanospheres with highly ordered periodic mesostructure [74] and lysozyme imprinted polymer beads [75] are also synthesized for the selective separation of proteins with different molecular sizes.…”