A novel magnetic silica support for use in chromatographic and enzymatic bioprocessing

Goetz, V; Remaud, M.; Graves, Donald H.

doi:10.1002/bit.260370704

Cited by 32 publications

(16 citation statements)

References 30 publications

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“…Magnetic supports (microspheres, nanospheres and ferrofluids) have been widely used in the field of biology and medicine such as in protein and enzyme immobilization, immunoassay, RNA and DNA purification, cell isolation and target drug [1][2][3][4][5][6][7][8]. These magnetic supports usually consist of inorganic magnetic cores (such as magnetite, haematite, nickel, alloys of cobalt, etc.)…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of amino–silane modified superparamagnetic silica nanospheres

Liu

Jian-wei

et al. 2004

Journal of Magnetism and Magnetic Materials

495

119

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Section: Introductionmentioning

confidence: 99%

Preparation and characterization of amino–silane modified superparamagnetic silica nanospheres

Liu

Jian-wei

et al. 2004

Journal of Magnetism and Magnetic Materials

495

119

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“…Two-step polymerization of MTLP was less efficient and resulted in broader distribution of particle size than the process of forming NMLP. However, coating of magnetite with polymers during the first step followed by further growth of particles during the second step was deemed necessary to fully enclose magnetite within the interior of the latex and to prevent inactivation of surface-bound enzyme by exposed metal ions (20,21). This is evident from the transmission electron photomicrograph of MTLP in Figure 2, where ultrafine magnetite, shown as the dark regions inside the TLP, was effectively covered by polymer matrix.…”

Section: Properties Of Nonmagnetic and Magnetic Latexmentioning

confidence: 90%

Latex Particles with Thermo‐Flocculation and Magnetic Properties for Immobilization of α‐Chymotrypsin

Chen

2001

Biotechnology Progress

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Core-shell-type latex particles composed of styrene, N-isopropylacrylamide (NIPAAm), and N-acryloxysuccinimide (NAS) were synthesized by surfactant-free emulsion polymerization. The latex particles show thermo-flocculation behavior due to the presence of temperature-sensitive monomer NIPAAm and could be used for immobilization of alpha-chymotrypsin through covalent bonding with the reactive ester groups of NAS. Enzyme recycle could be accomplished in this immobilized enzyme system by sedimentation of the thermo-flocculated latex particles in 20 min at 30 degrees C by raising the salt (NaCl) concentration to 0.5 M. To further enhance the sedimentation rate, ultrafine magnetite particles were prepared and included during polymerization to produce magnetic temperature-sensitive latex particles (MTLP), which could be recovered 6 times faster after thermo-flocculation by applying a low magnetic field. However, a higher salt concentration was necessary to flocculate the MTLP under the same condition as a result of its increased surface hydrophilicity, which originates from different polymerization conditions and the incorporation of magnetite. The immobilized enzyme shows high activity even against macromolecular substrates (hemoglobin and casein) owing to limited diffusion resistance, with full activity retention for nonmagnetic latex but one-half reduction in activity if the magnetic property was introduced. Optimal enzyme immobilization pH and enzyme loading were determined, and properties of the immobilized enzyme were characterized. The immobilized enzyme was used in 10 repeated batch hydrolyses of casein with successive flocculation/dispersion cycles and showed less than 15% activity decrease at the end. Overall, introducing the magnetic property to the latex could effectively enhance the solid-liquid separation rate after thermo-flocculation and maintain enzyme activity after repeated use but adversely influence the activity of the immobilized enzyme.

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“…However, to obtain binding kinetics that are similar to those obtained in conventional systems, the superficial velocities (U o ) in the MSFB should be similar to those commonly used in HPLC systems (typically 0.1 to 0.2 mm s −1 ) (Graves, 1993). MSFB chromatography beads reported to date have U mf values some 10 to 50 times greater than this, so materials with a lower density may be more appropriate (Burns, 1986;Goetz et al, 1991;. MSFB chromatography beads reported to date have U mf values some 10 to 50 times greater than this, so materials with a lower density may be more appropriate (Burns, 1986;Goetz et al, 1991;.…”

Section: Introductionmentioning

confidence: 96%

“…Few MSFB chromatography beads have been reported in the literature to date (Burns, 1986;Goetz et al, 1991;. Those that have been reported all have disadvantages, with the major drawbacks being that:…”

Section: Introductionmentioning

confidence: 99%

Preparation of magnetically susceptible polyacrylamide/magnetite beads for use in magnetically stabilized fluidized bed chromatography

Cocker

Fee

Evans

1997

Biotechnol. Bioeng.

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Spherical polyacrylamide/magnetite (PAM) composite beads, suitable for use in a magnetically stabilized fluidized bed (MSFB), were manufactured by a suspension polymerization method. Yield of beads depended on the type and concentration of buffer used during polymerization as well as the pH. More stabilizer was needed to prevent bead agglomeration as magnetite concentration increased. Bead diameter ranged from less than 60 to 600 µm, depending on reaction conditions, and the bead mean diameter and size distribution decreased with increasing impeller speed. The density and roundness factor of the beads were 1.19 ± 0.02 g cm −3 and 1.08 ± 0.03, respectively. The beads had high magnetization at a low applied magnetic field strength (60 mT at 75 kA m −1 ) and retained little residual magnetization (<2 mT) after the field was removed. Incorporation of magnetite did not significantly affect the physical strength of the beads: the beads' average elastic modulus was 14 ± 4 kPa, similar to reported values for polyacrylamide gels (15.8 kPa). The beads were stable in a range of buffers from pH 1 to 10 and were resistant to microbial degradation. The fluidization and stabilization behavior of the beads was examined in a bench-scale MSFB. The minimum fluidization velocity (U mf ) of the beads (0.035 mm s −1 ) allowed the MSFB to be operated at superficial velocities close to those used in HPLC systems. Against expectations, at high superficial velocities, the stabilized bed of the MSFB had a greater expansion than the unstabilized bed. The PAM beads could be derivatized and activated for soybean trypsin inhibitor immobilization by a standard carbodiimide method, and the affinity separation of trypsin from chymotrypsin was demonstrated. The PAM beads show excellent potential for use in MSFB chromatography.

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A novel magnetic silica support for use in chromatographic and enzymatic bioprocessing

Cited by 32 publications

References 30 publications

Preparation and characterization of amino–silane modified superparamagnetic silica nanospheres

Preparation and characterization of amino–silane modified superparamagnetic silica nanospheres

Latex Particles with Thermo‐Flocculation and Magnetic Properties for Immobilization of α‐Chymotrypsin

Preparation of magnetically susceptible polyacrylamide/magnetite beads for use in magnetically stabilized fluidized bed chromatography

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