Simple Synthesis of Functionalized Superparamagnetic Magnetite/Silica Core/Shell Nanoparticles and their Application as Magnetically Separable High‐Performance Biocatalysts

Abstract

Uniformly sized silica-coated magnetic nanoparticles (magnetite@silica) are synthesized in a simple one-pot process using reverse micelles as nanoreactors. The core diameter of the magnetic nanoparticles is easily controlled by adjusting the w value ([polar solvent]/[surfactant]) in the reverse-micelle solution, and the thickness of the silica shell is easily controlled by varying the amount of tetraethyl orthosilicate added after the synthesis of the magnetite cores. Several grams of monodisperse magnetite@silica nanoparticles can be synthesized without going through any size-selection process. When crosslinked enzyme molecules form clusters on the surfaces of the magnetite@silica nanoparticles, the resulting hybrid composites are magnetically separable, highly active, and stable under harsh shaking conditions for more than 15 days. Conversely, covalently attached enzymes on the surface of the magnetite@silica nanoparticles are deactivated under the same conditions.

Preparation and Characterization of Double Shell Fe3O4 Cluster@Nonporous SiO2@Mesoporous SiO2 Nanocomposite Spheres and Investigation of their In Vitro Biocompatibility

“…Moreover, NPs size is dependent on the constant rates of hydrolysis and condensation steps as a function of the reaction mixture (33). Similar to earlier works (17,(34)(35), we demonstrated that silica shell thickness around magnetite nanoparticles will increase with increasing the TEOS amount and the size of silica NPs. The latter itself is being increased by increasing the concentration of the precursor.…”

Fabrication of Silica Nanoparticles with Both Efficient Fluorescence and Strong Magnetization and Exploration of Their Biological Applications

“…The thickness of the silica shell, on the other hand, can be controlled by the TEOS concentration. [ 53,54 ] We also studied the effects of MNP-C, TEOS, and NH 4 OH concentrations on the sol-gel reactions. Under the conditions shown in Table S1, row 1, discrete, uniform nanoparticles are formed in MFSNP-1 ( Figure S3).…”

Two-Step Fabrication of Porous a#945;-Fe2O3@TiO2 core-shell Nanostructures with Enhanced Photocatalytic Activity

“…The synergetic effects between the core and shell materials may drastically improve the overall performance of the hybrid composites, which results in a range of potential applications, including biomedical application [3,4], catalysis [5,6], electronics [7] and chemical sensors [8]. The properties of core-shell nanostructures can be adjusted by changing either the constituting materials or the core to shell ratio [9].…”