title: Immobilization of the Enzyme Glucose Oxidase on Both Bulk and Porous SiO₂ Surfaces.
abstract: Silicon dioxide surfaces, both bulk and porous, were used to anchor the enzyme glucose oxidase. The immobilization protocol was optimized and the samples characterized using X-ray Photoelectron Spectroscopy, Energy Dispersive X-rays coupled to scanning electron microscopy and enzymatic activity measurements. We show that a uniform layer was obtained by activating the oxide before immobilization. X-ray Photoelectron Spectroscopy measurements carried out on bulk oxide showed that the silicon substrate signal was fully screened after the enzyme deposition showing the absence of uncovered surface regions. The enzyme presence was detected monitoring both the C 1s and N 1s signals. Finally, enzymatic activity measurements confirmed that the glucose oxidase activity was preserved after immobilization and maintained after three months of shelf life if the sample was properly stored. The importance of using porous silicon oxide to maximize the surface area was also evidenced.
authors.affiliation: CNR - IMM Stradale Primosole 50 Catania, Italy. sebania.libertino@imm.cnr.it.
authors.forename: Sebania
authors.initials: S
authors.lastname: Libertino
authors.affiliation: Università degli Studi di Catania, Dipartimento di Chimica Biologica, Chimica Medica e Biologia Molecolare, Catania, Italy. vera.aiello@imm.cnr.it.|Università degli Studi di Catania, Dipartimento di Scienze Biomediche, Catania, Italy. vera.aiello@imm.cnr.it.
authors.forename: Venera
authors.initials: V
authors.lastname: Aiello
authors.affiliation: Laboratorio Superfici e Interfasi (SUPERLAB), Consorzio Catania Ricerche, Catania, Italy. ascandura@unict.it.
authors.forename: Antonino
authors.initials: A
authors.lastname: Scandurra
authors.affiliation: Università degli Studi di Catania, Dipartimento di Chimica Biologica, Chimica Medica e Biologia Molecolare, Catania, Italy. renis@unict.it.
authors.forename: Marcella
authors.initials: M
authors.lastname: Renis
authors.affiliation: Università degli Studi di Catania, Dipartimento di Scienze Biomediche, Catania, Italy. sinatra@unict.it.
authors.forename: Fulvia
authors.initials: F
authors.lastname: Sinatra
keywords: Glucose oxidase; biosensor; enzymatic activity; glutaraldehyde; oxide activation; spectrophotometric assay