title: Nanosheet-based titania microspheres with hollow core-shell structure encapsulating horseradish peroxidase for a mediator-free biosensor.
abstract: Nanosheet-based titania (TiO(2)) microspheres with a hollow core-shell structure have been synthesized and employed to immobilize horseradish peroxidase (HRP) in order to fabricate a mediator-free biosensor. The morphology and structure of the TiO(2) microspheres were characterized by X-ray diffraction, scanning electron microscopy and transmission electronic microscopy. A possible growth mechanism has been proposed. Spectroscopic and electrochemical measurements revealed that the TiO(2) microspheres are an immobilization support with biocompatibility for enzymes, affording good enzyme stability and bioactivity. Due to the nanosheet-based hollow core-shell structure of the TiO(2) microspheres, the direct electron transfer of HRP is facilitated and the resulting biosensor displayed good performance for the detection of H(2)O(2), with both a low detection limit of 0.05 μM and a wide linear range of 0.4-140 μM, as well as a fast response and excellent long-term stability. The nanosheet-based TiO(2) microspheres with hollow core-shell structure, can be used for the efficient entrapment of other redox-active proteins and have wide potential applications in biosensors, biocatalysis, biomedical devices and bioelectronics.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Xie
authors.forename: Yingying
authors.initials: Y
authors.lastname: Zhao
authors.forename: Xu
authors.initials: X
authors.lastname: Chen
authors.forename: Haimei
authors.initials: H
authors.lastname: Liu
authors.forename: David G
authors.initials: DG
authors.lastname: Evans
authors.forename: Wensheng
authors.initials: W
authors.lastname: Yang
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D002244:Carbon / Q000737:chemistry; D004560:Electricity; D055664:Electrochemical Techniques / Q000295:instrumentation; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000378:metabolism*; D005465:Fluorocarbon Polymers / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D006735:Horseradish Peroxidase / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000032:analysis; D008863:Microspheres; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D004800:Enzymes, Immobilized; D005465:Fluorocarbon Polymers; C009495:titanium dioxide; C040402:perfluorosulfonic acid; D002244:Carbon; D006861:Hydrogen Peroxide; D014025:Titanium; D006735:Horseradish Peroxidase