title: Graphite nanosheet-based composites for mediator-free H2O2 biosensor.
abstract: Graphite nanosheet (GNS)-Nafion composites were prepared for the immobilization of hemoglobin (Hb) to construct a mediator-free H(2)O(2) biosensor. Scanning electron microscopy (SEM), UV-vis spectroscopy and Fourier transform infrared spectroscopy were used to characterize the Hb-GNS-Nafion composite film. Due to good biocompatibility of the composite film, immobilized Hb retained its native structure. The Hb-GNS-Nafion composite film-modified electrodes showed direct electrochemistry with a fast electron-transfer rate (6.63 s(-1)) and high electrocatalytic activity to the reduction of hydrogen peroxide (H(2)O(2)). The resulting biosensor exhibited a high sensitivity of 412.7 mA M(-1) cm(-2), a low detection limit of 2.0 x 10(-7) M, and a small apparent Michaelis-Menten constant of 37 microM. These results were comparable or superior to the biosensors based on the carbon nanofiber (CNF)- and carbon nanotube (CNT)-based biosensors. Due to the lower cost of GNSs, the GNS-based composite can combine with other redox proteins and widely apply in mediator-free biosensors, bioelectronics and biofuel cells.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China.
authors.forename: Xu
authors.initials: X
authors.lastname: Chen
authors.forename: Chenglin
authors.initials: C
authors.lastname: Fu
authors.forename: Wensheng
authors.initials: W
authors.lastname: Yang
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D002138:Calibration; D002417:Cattle; D004563:Electrochemistry; D004566:Electrodes; D005465:Fluorocarbon Polymers / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D006454:Hemoglobins / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000032:analysis*; D055767:Immobilized Proteins / Q000737:chemistry; D053761:Nanocomposites / Q000737:chemistry*; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D005465:Fluorocarbon Polymers; D006454:Hemoglobins; D055767:Immobilized Proteins; C040402:perfluorosulfonic acid; D006108:Graphite; D006861:Hydrogen Peroxide