title: On the stability of the "wired" bilirubin oxidase oxygen cathode in serum.
abstract: Oxygen is electroreduced to water on the "wired" bilirubin oxidase (w-BOD) catalyst at a considerably lesser potential than on pure platinum. The w-BOD catalyst could be of value in an implantable glucose-O2 biofuel cell, operating living tissue, if it were stable in serum. We found, however, that w-BOD loses its activity in a few hours in the combined presence of the urate and O2, both of which are normal serum constituents (Bioelectrochemistry, 2004, 65, 83-88). Here we report a second major instability: When the disconnected w-BOD cathode is allowed, in the absence of urate, to poise itself at the potential of the O2/H2O half cell at pH 7.2, it loses its activity rapidly. Unlike the urate/O2 caused loss, this loss can be avoided either by applying a potential that is reducing relative to the O2/H2O half-cell potential, or by excluding O2 and adding a mildly reducing reagent, such as urate. The w-BOD cathode can be stored, therefore, in deoxygenated serum, which contains urate.
authors.affiliation: Department of Chemistry, Chonbuk National University, Chonju 561-756, South Korea.
authors.forename: Chan
authors.initials: C
authors.lastname: Kang
authors.forename: Hyosul
authors.initials: H
authors.lastname: Shin
authors.forename: Adam
authors.initials: A
authors.lastname: Heller
mesh_terms: D000818:Animals; D004563:Electrochemistry; D004795:Enzyme Stability; D010084:Oxidation-Reduction; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000378:metabolism*; D010100:Oxygen / Q000097:blood* / Q000737:chemistry / Q000378:metabolism*; D013712:Tenebrio / Q000201:enzymology; D014867:Water / Q000737:chemistry / Q000378:metabolism
chemical_list: D014867:Water; D044925:Oxidoreductases Acting on CH-CH Group Donors; C042401:bilirubin oxidase; D010100:Oxygen