title: A reagentless enzymatic fluorescent biosensor for glucose based on upconverting glasses, as excitation source, and chemically modified glucose oxidase.
abstract: Upon near-infrared excitation Tm(3+)+Yb(3+) doped fluorohafnate glasses present upconversion properties and emit visible light. This property permits to use these glasses (UCG) as excitation sources for fluorescent optical biosensors. Taking this into account, in this work a fluorescent biosensor for glucose determination is designed and evaluated. The biosensor combines the UCG and the fluorescence of the enzyme glucose oxidase chemically modified with a fluorescein derivative (GOx-FS), whose intensity is modified during the enzymatic reaction with glucose. Optical parameters have been optimized and a mathematical model describing the behavior of the analytical signal is suggested. Working in FIA mode, the biosensor responds to glucose concentrations up to, at least, 15mM with a limit of detection of 1.9mM. The biosensor has a minimum lifetime of 9 days and has been applied to glucose determination in drinks. The applicability of the sensor was tested by glucose determination in two fruit juices.
authors: Analytical Biosensors Groups, Analytical Chemistry Department, Faculty of Sciences, Aragon Institute of Nanoscience, University of Zaragoza, Zaragoza, 50009 Spain; Chemical Technology for Separation and Detection Group, Instituto de Carboquímica-CISC, Zaragoza, 50018 Spain.
authors: Melisa
authors: M
authors: Del Barrio
authors: Liquid Crystals and Polymers group, Condensed Matter Physics Department, Faculty of Sciences, ICMA, University of Zaragoza, Zaragoza, 50009 Spain.
authors: Rafael
authors: R
authors: Cases
authors: Chemical Technology for Separation and Detection Group, Instituto de Carboquímica-CISC, Zaragoza, 50018 Spain.
authors: Vicente
authors: V
authors: Cebolla
authors: Institute of Analytical Chemistry, Chemo, and Biosensors, University of Regensburg, Regensburg, 93040 Germany.
authors: Thomas
authors: T
authors: Hirsch
authors: Analytical Biosensors Groups, Analytical Chemistry Department, Faculty of Sciences, Aragon Institute of Nanoscience, University of Zaragoza, Zaragoza, 50009 Spain.
authors: Susana
authors: S
authors: de Marcos
authors: Institute of Analytical Chemistry, Chemo, and Biosensors, University of Regensburg, Regensburg, 93040 Germany.
authors: Stefan
authors: S
authors: Wilhelm
authors: Analytical Biosensors Groups, Analytical Chemistry Department, Faculty of Sciences, Aragon Institute of Nanoscience, University of Zaragoza, Zaragoza, 50009 Spain. Electronic address: jgalban@unizar.es.
authors: Javier
authors: J
authors: Galbán
mesh_terms: D015374:Biosensing Techniques; D004800:Enzymes, Immobilized / Q000737:chemistry*; D005453:Fluorescence; D005947:Glucose / Q000032:analysis* / Q000737:chemistry; D005949:Glucose Oxidase / Q000737:chemistry*; D057230:Limit of Detection
chemical_list: D004800:Enzymes, Immobilized; D005949:Glucose Oxidase; D005947:Glucose
keywords: Glucose Determination; Glucose Oxidase; Inner Filter Effect; Upconverting glasses