title: Carbon nanodots-chitosan composite film: a platform for protein immobilization, direct electrochemistry and bioelectrocatalysis.
abstract: A novel composite film based on carbon nanodots (CNDs) and chitosan was readily prepared and used as immobilization matrix to entrap a heme protein, hemoglobin (Hb) for direct electrochemistry and bioelectrocatalysis. A modified electrode was obtained by casting Hb-CNDs-chitosan composites on the glassy carbon (GC) electrode surface. Spectroscopic and electrochemical studies showed that Hb entrapped in the composite film remained in its native structures, and CNDs in the film can greatly facilitate DET between the protein and the GC electrode. The electron-transfer kinetics of Hb in composite film was qualitatively evaluated by using the Marcus theory, and the apparent heterogeneous electron-transfer rate constant (ks) was estimated to be 2.39(±0.03)s(-1) with Laviron equations. The modified electrode showed excellent electrocatalytic behavior to the substrate, hydrogen peroxide (H2O2). The linear current response for H2O2 was from 1×10(-6) to 1.18×10(-4)M with a detection limit of 0.27(±0.02)μM at the signal-to-noise ratio of 3, and the apparent Michaelis-Menten constant was 0.067(±0.02)mM. These important features of CNDs-chitosan film have implied to be a promising platform for elaborating bioelectrochemical devices such as biosensors and biofuel cells.
authors.affiliation: Laboratory of Functionalized Molecular Solids, Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China; Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China; Laboratory of Optical Probes and Bioelectrocatalysis (LOPAB), College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China.
authors.forename: Meili
authors.initials: M
authors.lastname: Sheng
authors.affiliation: Laboratory of Functionalized Molecular Solids, Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China; Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China; Laboratory of Optical Probes and Bioelectrocatalysis (LOPAB), College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Laboratory of Functionalized Molecular Solids, Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China; Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China; Laboratory of Optical Probes and Bioelectrocatalysis (LOPAB), College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China.
authors.forename: Junyong
authors.initials: J
authors.lastname: Sun
authors.affiliation: Laboratory of Functionalized Molecular Solids, Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China; Anhui Key Laboratory of Chemo/Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China; Laboratory of Optical Probes and Bioelectrocatalysis (LOPAB), College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China. Electronic address: fgao@mail.ahnu.edu.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
mesh_terms: D002384:Catalysis; D048271:Chitosan / Q000737:chemistry*; D003217:Conductometry / Q000295:instrumentation*; D004566:Electrodes; D004595:Electroplating / Q000379:methods*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008567:Membranes, Artificial; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D040081:Protein Array Analysis / Q000295:instrumentation*; D011485:Protein Binding
chemical_list: D008567:Membranes, Artificial; D048271:Chitosan
keywords: Bioelectrocatalysis; Biosensor; Carbon nanodots; Direct electron transfer; Hemoglobin; Hydrogen peroxide