title: Functionalization of carbon buckypaper for the sensitive determination of hydrogen peroxide in human urine.
abstract: Here we report on a new approach for the electrochemical detection of hydrogen peroxide (H(2)O(2)) based on the co-immobilization of horseradish peroxidase and methylene blue on the functionalized carbon buckypaper supported by a titanium substrate. Cyclic voltammetry was used to study and optimize the performance of the resulting electrochemical biosensor. The proposed biosensor exhibited high analytical performance towards the quantification of H(2)O(2) at the physiological pH 7.4. Under optimized conditions, the biosensor shows a wide linear response range from 0.1 × 10(-6) to 5 × 10(-4)M concentrations of H(2)O(2). The detection limit was determined to be 7.5 × 10(-8)M (based on S/N=3). Reproducibility and stability of the fabricated biosensor were examined with satisfactory results. The biological relevance of the developed electrochemical biosensor has been further studied by the determination of H(2)O(2) in human urine samples of normal volunteers prior to and following the ingestion of coffee. Increased levels of urinary H(2)O(2) concentration suggest that oxidative stress is induced by coffee drinking in humans. There is considerable interest in oxidative stress as relates to human physiology. The sensitive determination of H(2)O(2) in human urine may serve as a valuable biomarker to effectively elucidate specific levels of oxidative stress in vivo.
authors.affiliation: Department of Chemistry, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada.
authors.forename: Sanghamitra
authors.initials: S
authors.lastname: Chatterjee
authors.affiliation: Department of Chemistry, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada. Electronic address: aicheng.chen@lakeheadu.ca.
authors.forename: Aicheng
authors.initials: A
authors.lastname: Chen
mesh_terms: D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D003069:Coffee / Q000009:adverse effects; D055664:Electrochemical Techniques; D004800:Enzymes, Immobilized; D006735:Horseradish Peroxidase; D006801:Humans; D006861:Hydrogen Peroxide / Q000652:urine*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D008854:Microscopy, Electron; D037742:Nanotubes, Carbon / Q000648:ultrastructure; D018384:Oxidative Stress; D010209:Paper; D015203:Reproducibility of Results; D014025:Titanium
chemical_list: D003069:Coffee; D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D006861:Hydrogen Peroxide; D014025:Titanium; D006735:Horseradish Peroxidase