title: Mediatorless glucose biosensor and direct electron transfer type glucose/air biofuel cell enabled with carbon nanodots.
abstract: Utilization of carbon nanodots (CNDs), newcomers to the world of carbonaceous nanomaterials, in the electrochemistry realm has rarely been reported so far. In this study, CNDs were used as immobilization supports and electron carriers to promote direct electron transfer (DET) reactions of glucose oxidase (GOx) and bilirubin oxidase (BOD). At the CNDs electrode entrapped with GOx, a high rate constant (k(s)) of 6.28 ± 0.05 s(-1) for fast DET and an apparent Michaelis-Menten constant (K(M)(app)) as low as 0.85 ± 0.03 mM for affinity to glucose were found. By taking advantage of its excellent direct bioelectrocatalytic performances to glucose oxidation, a DET-based biosensor for glucose detection ranging from 0 to 0.64 mM with a high sensitivity of 6.1 μA mM(-1) and a limit of detection (LOD) of 1.07 ± 0.03 μM (S/N = 3) was proposed. Additionally, the promoted DET of BOD immobilized on CNDs was also observed and effectively catalyzed the reduction of oxygen to water at the onset potential of +0.51 V (vs Ag/AgCl). On the basis of the facilitated DET of these two enzymes at CNDs electrodes, a mediator-free DET-type glucose/air enzymatic biofuel cell (BFC), in which CNDs electrodes entrapped with GOx and BOD were employed for oxidizing glucose at the bioanode and reducing oxygen at the biocathode, respectively, was successfully fabricated. The constructed BFC displayed an open-circuit voltage (OCV) as high as 0.93 V and a maximum power density of 40.8 μW cm(-2) at 0.41 V. These important features of CNDs have implied to be promising materials for immobilizing enzymes and efficient platforms for elaborating bioelectrochemical devices such as biosensors and BFCs.
authors: Laboratory of Functionalized Molecular Solids, Ministry of Education, Anhui Key Laboratory of Chemo/Biosensing, Laboratory of Optical Probes and Bioelectrocatalysis, College of Chemistry and Materials Science, Anhui Normal University , Wuhu 241000, People's Republic of China.
authors: Mei
authors: M
authors: Zhao
authors: Yue
authors: Y
authors: Gao
authors: Junyong
authors: J
authors: Sun
authors: Feng
authors: F
authors: Gao
mesh_terms: D056804:Biofuels; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002244:Carbon / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D004579:Electron Transport; D004583:Electrons; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D005947:Glucose / Q000032:analysis*; D005949:Glucose Oxidase / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D057230:Limit of Detection; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000737:chemistry / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D056804:Biofuels; D004800:Enzymes, Immobilized; D002244:Carbon; D005949:Glucose Oxidase; D044925:Oxidoreductases Acting on CH-CH Group Donors; C042401:bilirubin oxidase; D005947:Glucose; D010100:Oxygen