ALGORITHMS FOR CALIBRATING AN ANALYTE SENSOR
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Abstract
Disclosed are embodiments that relate to algorithms and methods for calibrating an analyte sensor, and more particularly, to algorithms for calibrating an optical glucose sensor comprising an equilibrium fluorescent chemical indicator system. In particular, a method of detecting an analyte concentration is disclosed where a modified Michaelis-Menten equation comprising Michaelis-Menten parameters is used to characterize the signal generated by the analyte sensor.
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Citations
29 Claims
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1. -15. (canceled)
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16. A measurement device for estimating glucose concentration comprising:
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an optical sensor including a non-enzymatic, equilibrium fluorescence chemical indicator system disposed along a distal region of an optical fiber, the chemical indicator system including a fluorophore operably coupled to a glucose binding moiety, wherein the fluorophore is configured to generate a fluorescent emission signal upon excitation with light, and wherein glucose binding to the glucose binding moiety causes a change in the fluorescent emission signal related to the glucose concentration in the physiologic fluid; and a processing module configured to transform the fluorescent emission signal intensity into a glucose concentration value using the equation;
[G]=c*(I−
a)/(a+b−
I), wherein[G] is the glucose concentration, I is the fluorescent emission signal intensity, a is the value of the fluorescent emission signal intensity in the absence of glucose, b is the value of the asymptotic signal intensity at infinite glucose concentration, minus the fluorescent signal intensity in the absence of glucose (a), and c is the value of the glucose concentration at which the fluorescent signal intensity is one-half the difference between the asymptotic value (b) and the background (a). - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A measurement device for estimating glucose concentration comprising:
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an optical sensor including a non-enzymatic, equilibrium fluorescence chemical indicator system disposed along a distal region of an optical fiber, the chemical indicator system including a fluorophore operably coupled to a glucose binding moiety, wherein the fluorophore is configured to generate a fluorescent emission signal upon excitation with light, and wherein glucose binding to the glucose binding moiety causes a change in the fluorescent emission signal related to the glucose concentration in the physiologic fluid; a detector operable to measure a fluorescent emission signal intensity generated by the fluorophore; and a processing module configured to transform the fluorescent emission signal intensity into a glucose concentration value based on a value of the fluorescent emission signal intensity in the absence of glucose, a value of the asymptotic intensity of the fluorescent emission signal at infinite glucose, and a value of the glucose concentration at which the fluorescent emission intensity is one-half the difference between the fluorescent emission signal intensity in the absence of glucose and the asymptotic intensity of the fluorescent emission signal at infinite glucose, using the equation;
[G]=c*(I−
a)/(a+b−
I), wherein[G] is the glucose concentration, I is the fluorescent emission signal intensity, a is the value of the fluorescent emission signal intensity in the absence of glucose, b is the value of the asymptotic signal intensity at infinite glucose concentration, minus the fluorescent signal intensity in the absence of glucose (a), and c is the value of the glucose concentration at which the fluorescent signal intensity is one-half the difference between the asymptotic value (b) and the background (a).
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29. A measurement device for estimating glucose concentration comprising:
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an optical sensor including a non-enzymatic, equilibrium fluorescence chemical indicator system disposed along a distal region of an optical fiber, the chemical indicator system including a fluorophore operably coupled to a glucose binding moiety, wherein the fluorophore is configured to generate a fluorescent emission signal upon excitation with light, and wherein glucose binding to the glucose binding moiety causes a change in the fluorescent emission signal related to the glucose concentration in the physiologic fluid; and a processing module configured to transform the fluorescent emission signal intensity into a glucose concentration value using the equation;
F=Fmin+FmaxK[X]/(1+K[X]), wherein[X] is the glucose concentration, F is the fluorescent emission signal intensity, Fmin is the fluorescent emission signal intensity in the absence of glucose, Fmax is the maximum fluorescent emission signal intensity when the system is saturated with glucose, and K is the binding affinity of the glucose binding moiety of the chemical indicator system.
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Specification