System and method for dynamically calibrating and measuring analyte concentration in diabetes management monitors
View Patent ↗An optical analyte sensor and diabetes management system is provided. The sensor preferably includes a hydrogel matrix for receiving a sample containing an analyte at unknown concentration, a light emitter for emitting light at a stimulation frequency, a light receiver for receiving a fluorescence signal at a first isosbestic frequency, and at a second frequency, for measuring an intensity of the fluorescence signal and the first and second frequencies. A processor determines a concentration of the analyte based on the respective intensities.
1. An optical analyte sensor for determining a concentration of glucose, comprising:
a glucose permeable hydrogel matrix comprising a glucose binding protein (GBP) that adopts a first conformation in the presence of glucose, and a second conformation in the absence of glucose, the conformational change resulting in a different fluorescence emission intensity, the matrix adapted to receive a sample containing glucose at an unknown concentration;
wherein the GBP within the glucose permeable hydrogel matrix is adapted to fluoresce at an intensity invariant to the glucose concentration within the matrix at an isosbestic frequency when subjected to an excitation source, and to fluoresce at an intensity that varies according to glucose concentration at a second frequency when subjected to an excitation source;
a reference filter optically coupled to the matrix that passes a reference fluorescence emission from the matrix at a reference frequency, the reference frequency being an isosbestic frequency relative to the glucose binding protein, wherein the reference filter is a bandpass filter having an optimal bandpass range around the isosbestic frequency, a signal filter optically coupled to the matrix that passes a signal fluorescence emission from the matrix at a signal frequency, the signal frequency being an intensity variant frequency relative to the glucose binding protein, wherein the signal filter is a bandpass filter having a bandpass range selected to optimize detected power;
a photodetector to detect an intensity of the reference fluorescence emission and an intensity of the signal fluorescence emission; and
a processor adapted to compare the fluorescence intensity of the reference fluorescence emission and the signal fluorescence emission, and to determine a glucose concentration based on the relative intensities.
2. The optical analyte sensor as claimed in claim 1 , wherein the sensor is an in-vitro sensor.
3. The optical analyte sensor as claimed in claim 1 , wherein the sensor is an in-vivo sensor.
4. The optical analyte sensor as claimed in claim 1 , wherein the sensor is a continuous sensor.
5. The optical analyte sensor as claimed in claim 1 , wherein the analyte is hemoglobin HbA1c.
6. The optical analyte sensor as claimed in claim 1 , wherein the analyte is glycated albumin.
7. The optical analyte sensor as claimed in claim 1 , wherein the matrix comprises boronic acid.