title: Electrochemical approach for detection of extracellular oxygen released from erythrocytes based on graphene film integrated with laccase and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid).
abstract: This work develops a novel electrochemical approach for detection of the extracellular oxygen released from human erythrocytes. The sensing is based on the bioelectrocatalytic system of graphene integrated with laccase (Lac) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) toward the reduction of oxygen. ABTS and laccase are assembled on the surface of graphene, which is synthesized by a chemistry route, utilizing the pi-pi and electrostatic interactions of these components. Transmission electron microscopy (TEM), atomic force microscopy (AFM), and FT-IR spectroscopy demonstrate that graphene has been successfully synthesized, and ABTS and laccase have been effectively assembled on a graphene surface with the formation of Lac-ABTS-graphene hybrid. The voltammetric results indicate that ABTS can be used as a redox mediator when it is in immobilized form. The hybrid deposited on the glassy carbon (GC) electrode is demonstrated to be a good bioelectrocatalyst for the reduction of oxygen with inherent enzyme activity, accepted stability, high half-wave potential (ca.670 mV vs NHE), and unimpeded electrical communication to the copper redox sites of laccase. Therefore, this study has not only established a novel approach of detection of extracellular oxygen but also provided a general route for fabricating a graphene-based biosensing platform via assembling enzymes/proteins on a graphene surface.
authors.affiliation: Jiangsu Key Laboratory of Biofunctional Materials, Laboratory of Electrochemistry, College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097, PR China.
authors.forename: Xiuming
authors.initials: X
authors.lastname: Wu
authors.forename: Yaojuan
authors.initials: Y
authors.lastname: Hu
authors.forename: Juan
authors.initials: J
authors.lastname: Jin
authors.forename: Ninglin
authors.initials: N
authors.lastname: Zhou
authors.forename: Ping
authors.initials: P
authors.lastname: Wu
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Chenxin
authors.initials: C
authors.lastname: Cai
mesh_terms: D052160:Benzothiazoles; D004563:Electrochemistry / Q000379:methods*; D004912:Erythrocytes / Q000378:metabolism*; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D042845:Laccase / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D010100:Oxygen / Q000032:analysis / Q000378:metabolism*; D013451:Sulfonic Acids / Q000737:chemistry*; D013844:Thiazoles / Q000737:chemistry*
chemical_list: D052160:Benzothiazoles; D013451:Sulfonic Acids; D013844:Thiazoles; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D006108:Graphite; D042845:Laccase; D010100:Oxygen