title: Enzyme immobilization and direct electrochemistry based on a new matrix of phospholipid-monolayer-functionalized graphene.
abstract: A new nanocomposite material for enzyme immobilization and subsequent direct electrochemistry and electrocatalysis was developed by using 1,2-dimyristoyl-sn-glycero-3-phospho-(1-rac-glycerol)-phospholipid-monolayer-membrane-modified graphene (DMPG-G). Microperoxidase-11 (MP11) was chosen as a model enzyme to investigate the composite system. Owing to the improved conductivity and biocompatible microenvironment, MP11 that was immobilized in the matrix of the DMPG-G nanocomposite (DMPG-G-MP11) effectively retained its native structure and bioactivity. DMPG-G-MP11-modified glassy carbon electrode (DMPG-G-MP11/GCE) exhibited a pair of well-defined quasi-reversible redox peaks of MP11 and showed high electrocatalytic activity towards hydrogen peroxide (H(2)O(2)). The linear response of the developed biosensor for the determination of H(2)O(2) ranged from 2.0×10(-6) to 4.5×10(-4)  M with a detection limit of 7.2×10(-7)  M. This biosensor exhibited high reproducibility and long-term storage stability. The promising features of this biosensor indicate that these lipid-graphene nanocomposites are ideal candidate materials for the direct electrochemistry of redox proteins and that they could serve as a versatile platform for the construction of a third-generation biosensor.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China.
authors.forename: Jiyang
authors.initials: J
authors.lastname: Liu
authors.forename: Lei
authors.initials: L
authors.lastname: Han
authors.forename: Tianshu
authors.initials: T
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Hong
authors.forename: Yaqing
authors.initials: Y
authors.lastname: Liu
authors.forename: Erkang
authors.initials: E
authors.lastname: Wang
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D006108:Graphite / Q000737:chemistry*; D006736:Horses; D006861:Hydrogen Peroxide / Q000032:analysis*; D057230:Limit of Detection; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D010544:Peroxidases / Q000737:chemistry / Q000378:metabolism*; D010743:Phospholipids / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D010743:Phospholipids; D006108:Graphite; D006861:Hydrogen Peroxide; D010544:Peroxidases; C021799:microperoxidase