title: Glucose biosensor based on the room-temperature phosphorescence of TiO2/SiO2 nanocomposite.
abstract: The direct immobilization of glucose oxidase (GOD) on TiO2/SiO2 nanocomposite and its application as glucose biosensor were investigated. The room-temperature phosphorescence of TiO2/SiO2 nanocomposite can be quenched by hydrogen peroxide (H(2)O(2)). The detection of glucose may be accomplished by monitoring the formation of hydrogen peroxide which generated in the oxidation process of glucose with the catalysis of GOD. To our surprise, by using a 96-hole polyporous plate accessory of fluorescence spectrophotometer, the biosensor exhibits excellent linear response to glucose concentrations ranging from 1.0 x 10(-9) to 1.0 x 10(-2)M with a detection limit of 1.2 x 10(-10)M. The TiO2/SiO2 nanocomposite can be used as both supporting material and signal transducer. The phosphorescence intensity and color of the biosensor change obviously and even could be observed with naked eyes by continuous addition of glucose. Based on the room-temperature phosphorescence of TiO2/SiO2 nanocomposite, a new method of solid substrate-room-temperature phosphorimetry (SS-RTP) for glucose determination is proposed. A glucose biosensor was fabricated with wide determination concentration range, low detection limit, high sensitivity, and fast response time. And the biosensor has been successfully applied to the determination of glucose in human blood serum. The coacervation of GOD enzyme and its interaction with TiO2/SiO2 nanocomposite enlarge the surface area and enhance the chemical stability of GOD. The nice biocompatibility, large surface area, good chemical stability and nontoxicity of the TiO2/SiO2 nanocomposite have made this material suitable for functioning as biosensor.
authors.affiliation: Key Laboratory of Green Chemistry and Technology (Sichuan University), College of Chemistry, Sichuan University, Chengdu 610064, PR China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Liu
authors.forename: Hongyan
authors.initials: H
authors.lastname: Yuan
authors.forename: Dan
authors.initials: D
authors.lastname: Xiao
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005947:Glucose / Q000032:analysis*; D005949:Glucose Oxidase / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000032:analysis; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation; D012822:Silicon Dioxide / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*; D013696:Temperature; D014025:Titanium / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; C009495:titanium dioxide; D012822:Silicon Dioxide; D006861:Hydrogen Peroxide; D014025:Titanium; D005949:Glucose Oxidase; D005947:Glucose