title: Direct electron transfer in nanostructured sol-gel electrodes containing bilirubin oxidase.
abstract: Bilirubin oxidase encapsulated within a silica sol-gel/carbon nanotube composite electrode effectively catalyzed the reduction of molecular oxygen into water through direct electron transfer at the carbon nanotube electrode surface. In this nanocomposite approach, the silica matrix is designed to be sufficiently porous for substrate molecules to have access to the enzyme and yet provides a protective cage for immobilization without affecting biological activity. The incorporation of carbon nanotubes adds electrical connectivity and increases active electrode surface area. The standard surface electron transfer rate constant was calculated to be 59 s(-1) which indicates that the carbon nanotube side walls are primarily responsible for electron transfer. The use of direct electron transfer processes simplifies biofuel cell fabrication by eliminating the need for redox mediator and ion-conducting separators.
authors.affiliation: Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, California 90095, USA.
authors.forename: James
authors.initials: J
authors.lastname: Lim
authors.forename: Nicolas
authors.initials: N
authors.lastname: Cirigliano
authors.forename: John
authors.initials: J
authors.lastname: Wang
authors.forename: Bruce
authors.initials: B
authors.lastname: Dunn
mesh_terms: D015374:Biosensing Techniques; D011211:Electric Power Supplies; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004579:Electron Transport; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008839:Microelectrodes; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000737:chemistry*; D010316:Particle Size
chemical_list: D004800:Enzymes, Immobilized; D044925:Oxidoreductases Acting on CH-CH Group Donors; C042401:bilirubin oxidase