title: Synthesis and characterization of biocatalytic γ-Fe2O3@SiO2 particles as recoverable bioreactors.
abstract: In this work, we present a suitable methodology to produce magnetically recoverable bioreactors based on enzymes, which are covalently attached on the surface of iron oxide@silica nanoparticles. In order to produce this system, iron oxide clusters with a mean diameter of 68 nm were covered with silica. This strategy yields spherical γ-Fe2O3@SiO2 cluster@shell nanoparticles with a mean diameter of 200 nm which present magnetic responsiveness and enhanced stability. The surface of these nanoparticles was modified into two steps with the aim to obtain carboxylic functional groups, which were activated to react with the enzyme glucose oxidase (GOx) that was thus immobilized on the surface of the nanoparticles. The objective of this chemistry at the nanoparticles interface is to produce magnetic-responsive bioreactors. The enzymatic activity was evaluated by using the recoverable bioreactors as part of an amperometric biosensor. These measurements allowed determining the stability, catalytic activity and the amount of enzyme immobilized on the surface of the nanoparticles. Furthermore, the functionalized nanoparticles can be recovered by applying an external magnetic field, which allows them to be employed in chemical processes where the recovery of the biocatalyst is important.
authors.affiliation: Department of Physical-Chemistry II, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain.
authors.forename: A M
authors.initials: AM
authors.lastname: Vaz
authors.affiliation: Department of Physical-Chemistry II, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Serrano-Ruiz
authors.affiliation: Department of Physical-Chemistry II, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Laurenti
authors.affiliation: Department of Physical-Chemistry II, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Alonso-Cristobal
authors.affiliation: Department of Physical-Chemistry II, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Lopez-Cabarcos
authors.affiliation: Department of Physical-Chemistry II, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain. Electronic address: bjrubio@ucm.es.
authors.forename: J
authors.initials: J
authors.lastname: Rubio-Retama
mesh_terms: D055162:Biocatalysis; D019149:Bioreactors; D004800:Enzymes, Immobilized / Q000378:metabolism; D005290:Ferric Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D019793:Fluorescein / Q000737:chemistry / Q000378:metabolism; D005949:Glucose Oxidase / Q000378:metabolism; D058185:Magnetite Nanoparticles / Q000648:ultrastructure; D010316:Particle Size; D059027:Recycling; D012822:Silicon Dioxide / Q000138:chemical synthesis* / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D004800:Enzymes, Immobilized; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; C000499:ferric oxide; D012822:Silicon Dioxide; D005949:Glucose Oxidase; D019793:Fluorescein
keywords: Bioreactors; Enzymes; Magnetic nanoparticles