Covalent Immobilization of Glucose Oxidase on Well-Defined Poly(glycidyl methacrylate)−Si(111) Hybrids from Surface-Initiated Atom-Transfer Radical Polymerization

Abstract

A simple one-step procedure was employed for the covalent immobilization of an atom-transfer radical polymerization (ATRP) initiator, via the robust Si-C bond, on the hydrogen-terminated Si(111) surface (Si-H surface). Well-defined poly(glycidyl methacrylate) [P(GMA)] brushes, tethered directly on the (111)-oriented single-crystal silicon surface, were prepared via surface-initiated ATRP. Kinetics study on the surface-initiated ATRP of glycidyl methacrylate revealed that the chain growth from the silicon surface was consistent with a "controlled" process. A relatively high concentration of glucose oxidase (GOD; above 0.2 mg/cm2) could be coupled directly to the well-defined P(GMA) brushes via the ring-opening reaction of the epoxide groups with the amine moieties of the enzyme. The resultant GOD-functionalized P(GMA) brushes, with the accompanying hydroxyl groups from the ring-opening reaction of the epoxide groups, serves as an effective spacer to provide the GOD with a higher degree of conformational freedom and a more hydrophilic environment. An equivalent enzyme activity above 1.6 units/cm2 [micromoles of beta-D-(+)-glucose oxidized to d-gluconolactone per minute per square centimeter] and a corresponding relative activity of about 60% could be readily achieved. The immobilized GOD also exhibited an improved stability during storage over that of the free enzyme. The GOD-functionalized silicon substrates are potentially useful to the development of silicon-based glucose biosensors.

Protein Immobilization onto Poly(acrylic acid) Functional Macroporous PolyHIPE Obtained by Surface-Initiated ARGET ATRP

“…1,2 Polymer brushes are particularly suited for covalent immobilization of biomolecules because they possess a well-defined structure, excellent mechanical stability and dense functional groups. 3,4,5,6,7,8,9,10 Moreover, the number of binding sites for biomolecules can be controlled by the polymer chain length. While this concept is particularly successful for planar and inorganic substrates, the decoration of there-dimensional macroporous polymeric substrates with polymer brushes provides a significantly bigger challenge.…”

Selective Controlled/Living Photoradical Polymerization of Glycidyl Methacrylate, Using a Nitroxide Mediator in the Presence of a Photosensitive Triarylsulfonium Salt

“…Poly(glycidyl methacrylate) (PGMA) and its copolymers have various industrial applications, such as coatings, adhesives, printing-ink, photo imaging [1], enzyme immobilization [2], and carbon dioxide fixation [3] based on the highly reactive pendant oxirane rings that provide the sequential ring-opening reactions. The oxirane rings have also attracted considerable attention from the viewpoint of the photopolymerization chemistry.…”

Piperazine-Containing Polymer Brush Layer as Supported Base Catalyst in a Glass Microreactor

“…After ring opening of the epoxide groups in the polymer brushes with 1-boc-piperazine (3), the contact angle increased from 69° [27] to a value of 79°. Upon removal of the boc group, the contact angle decreased to a value of 48°indicating the hydrophilic nature of the piperazine-supported polymer brushes.…”