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Updated: Mar 15, 2026
Fluorescent Nanoparticles for the Measurement of Ion Concentration in Biological Systems
Published on: July 4, 2011
A reagentless enzymatic fluorescent biosensor for glucose based on upconverting glasses, as excitation source, and
Melisa Del Barrio1, Rafael Cases2, Vicente Cebolla3
1Analytical 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.
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.
