title: Porous graphitized carbon monolith as an electrode material for probing direct bioelectrochemistry and selective detection of hydrogen peroxide.
abstract: For the first time, graphitized carbon particles with a high surface area have been prepared and evaluated as a new material for probing direct electrochemistry of hemoglobin (Hb). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) imaging revealed that the carbon monolithic skeleton was constructed by a series of mesopores with irregular shapes and an average pore diameter of ~5.6 nm. With a surface area of 239.6 m(2)/g, carbon particles exhibited three major Raman peaks as commonly observed for carbon nanotubes and other carbon materials, i.e., the sp(3) and sp(2) carbon phases coexisted in the sample. A glassy carbon electrode modified with carbon monoliths and didodecyldimethylammonium bromide exhibited direct electron transfer between Hb molecules and the underlying electrode with a transfer rate constant of 6.87 s(-1). The enzyme electrode displayed a pair of quasi-reversible reduction-oxidation peaks at -0.128 and -0.180 V, reflecting the well-known feature of the heme [Fe(3+)/Fe(2+)] redox couple: a surface-controlled electrochemical process with one electron transfer. This reagentless biosensing approach was capable of detecting H(2)O(2), a simple molecule but plays an important role in analytical and biological chemistry, as low as 0.1 μM with linearity of 0.1-60 μM and a response time of <0.8 s, comparing favorably with other carbon based electrodes (5 s).
authors.affiliation: Irish Separation Science Cluster, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: He
authors.forename: Lin
authors.initials: L
authors.lastname: Zhou
authors.forename: Ekaterina P
authors.initials: EP
authors.lastname: Nesterenko
authors.forename: Pavel N
authors.initials: PN
authors.lastname: Nesterenko
authors.forename: Brett
authors.initials: B
authors.lastname: Paull
authors.forename: Jesse O
authors.initials: JO
authors.lastname: Omamogho
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Glennon
authors.forename: John H T
authors.initials: JH
authors.lastname: Luong
mesh_terms: D015374:Biosensing Techniques; D002384:Catalysis; D055664:Electrochemical Techniques; D004566:Electrodes; D004579:Electron Transport; D006108:Graphite / Q000737:chemistry*; D006454:Hemoglobins / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000032:analysis*; D037742:Nanotubes, Carbon / Q000737:chemistry; D010084:Oxidation-Reduction; D016062:Porosity; D000644:Quaternary Ammonium Compounds / Q000737:chemistry
chemical_list: D006454:Hemoglobins; D037742:Nanotubes, Carbon; D000644:Quaternary Ammonium Compounds; C046112:didodecyldimethylammonium; D006108:Graphite; D006861:Hydrogen Peroxide