INDICATOR SYSTEM FOR FIBRE OPTIC SENSOR
The invention provides an optical sensor, e.g a fibre optic sensor, for determining the presence or amount of an analyte in a medium, the sensor having an indicator provided in the form of a fluid. In one aspect, the sensor contains either a solution of the indicator itself, or a solution of a support material which is bonded to the indicator. Dendrimers are examples of suitable support materials.
1 . An optical sensor for determining the amount or presence of an analyte in a medium, the sensor comprising a cell comprising (a) an indicator for the analyte or (b) a supported indicator comprising an indicator for the analyte bonded to a support material, wherein the indicator or supported indicator is in fluid form, and wherein the cell comprises one or more openings covered with an analyte-permeable membrane, the membrane being adapted to retain the indicator or supported indicator within the cell.
2 . A sensor according to claim 1 , wherein the cell comprises a solution of the indicator or supported indicator.
3 . A sensor according to claim 2 , wherein the cell comprises a supported indicator wherein the support material is a dendrimer.
4 . A sensor according to claim 3 , wherein the dendrimer is a polyamidoamine dendrimer.
5 . A sensor according to claim 3 , wherein the dendrimer is bound to at least 4 indicator moieties.
6 . A sensor according to claim 3 , wherein the dendrimer is symmetrical.
7 . A sensor according to claim 3 , wherein the dendrimer is bound to a water-soluble polymer.
8 . A sensor according to claim 1 , wherein the cell contains a fluid mixture comprising (i) water or an aqueous solution and (ii) a supported indicator, wherein the support material is a hydrogel having water dispersed therein, said hydrogel having water dispersed therein being in the form of a fluid.
9 . A sensor according to claim 8 , wherein the hydrogel has a water content of at least 30% w/w.
10 . A sensor according to claim 1 , wherein the indicator comprises a receptor and fluorophore and wherein the receptor and the fluorophore are separately bonded to a support material.
11 . A sensor according to claim 1 , wherein the analyte is glucose and the indicator comprises a receptor moiety having one or more boronic acid groups.
12 . A sensor according to claim 1 wherein the sensor is adapted to monitor the fluorescence intensity of the fluorophore.
13 . A sensor according to claim 1 wherein the sensor is adapted to monitor the fluorescence lifetime of the fluorophore.
14 . A kit comprising a sensor according to claim 1 , apparatus adapted to supply incident light to the optical waveguide, and a detector for detecting a returned signal.
15 . A method of manufacturing an optical sensor according to claim 1 , comprising providing a cell having one or more openings, inserting into the cell (a) an indicator or (b) a supported indicator comprising an indicator bonded to a support material, wherein the indicator or supported indicator is in fluid form, and covering one or more openings of the cell with an analyte-permeable membrane, the membrane being adapted to retain the indicator or supported indicator within the cell.
16 . A method of determining the presence or concentration of an analyte in a medium, the method comprising providing incident light to the cell of an optical sensor as defined in claim 1 and detecting a return optical signal.
17 . A method according to claim 16 , wherein the indicator comprises a fluorophore and wherein the method comprises measuring the fluorescence intensity of the fluorophore.
18 . A method according to claim 16 , wherein the indicator comprises a fluorophore and wherein the method comprises measuring the fluorescence lifetime of the fluorophore.