%0 Journal Article
%A Del Barrio Redondo, Melisa
%A Marcos, Susana de
%A Cebolla, Vicente
%A Heiland, Josef
%A Wilhelm, Stefan
%A Hirsch, Thomas
%A Galbán, Javier
%T Enzyme-induced modulation of the emission of upconverting nanoparticles: towards a new sensing scheme for glucose
%D 2014
%@ 0956-5663
%U https://hdl.handle.net/20.500.14352/93057
%X A new approach for the design of a fluorometric biosensor for continuous monitoring of glucose levels in biological samples based on near-infrared (NIR) excitation is described. The sensor combines the fluorescence of the enzyme glucose oxidase (GOx) chemically modified with a fluorescein derivative (FS) and the luminescent properties of upconverting luminescent nanoparticles (UCLNPs). Both, the chemically modified enzyme (GOx-FS) and the UCLNPs are immobilized in a poly(acrylamide) film as a physical support. The excitation of the UCLNPs with NIR light is of major advantage, since fluorescence background from the matrix is minimized. The upconverted luminescence is used to excite GOx-FS, which undergoes a change in the fluorescence intensity during the enzymatic reaction with glucose. The sensor comprises sufficient stability and covers the physiological range of glucose levels in blood. Furthermore, in a proof of principle experiment, the sensor system responds linearly to glucose concentrations in the range from 3.3 to 16.6. mM in flow injection analysis mode.
%~