CGM Sensor Parameter Extraction Using Probing Potential Modulation
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Solution Overview
Problem
Continuous glucose monitoring (CGM) sensors face challenges such as long break-in times, factory or in-situ calibration, and changes in sensitivity due to environmental factors, leading to inaccuracies in analyte concentration determination.
Innovation Solution
Employing probing potential modulations (PPMs) on top of the constant voltage applied to the sensor to measure primary and PPM current signals, using extracted parameters like R1, R4, and y45 to determine glucose concentrations, which are independent of electrode size and background interference, and provide rapid warm-up times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional constant voltage potential is applied to the sensor, then the sensor operates continuously, but sensor sensitivity changes due to environmental factors and long break-in times occur
Solution Approach 1:
The patent applies periodic probing potential modulations (PPMs) superimposed on the constant voltage potential. These periodic probes are applied at regular intervals to measure sensor response characteristics, which are then used to calculate correction factors that compensate for sensitivity drift and environmental variations, maintaining reliable glucose measurements throughout continuous operation
Solution Approach 2:
The patent implements a feedback mechanism where the sensor's response to PPM probes is continuously monitored and used to update correction factors. The processing system analyzes the probe responses and adjusts the conversion function parameters accordingly, creating a closed-loop system that compensates for sensor drift and environmental changes in real-time
2Measurement precision
If factory or in-situ calibration is performed, then sensor accuracy is improved, but calibration time and complexity increase
Solution Approach 1:
The patent enables the sensor to perform self-calibration by using its own response to the probing potential modulations. The sensor's inherent electrical characteristics when exposed to PPMs provide the calibration information needed to determine glucose concentration, eliminating the need for external calibration standards or procedures
Solution Approach 2:
The patent changes the electrical parameters applied to the sensor by superimposing AC probing potentials on the DC operating voltage. This allows the sensor to provide calibration information through its electrical response characteristics rather than requiring physical calibration materials, enabling rapid and accurate calibration
3Measurement precision
If background interference is present in the measurement, then measurement accuracy decreases, but signal processing complexity increases
Solution Approach 1:
The patent uses periodic probing potential modulations that create characteristic current responses distinct from background interference. By analyzing the sensor's response to these periodic probes, the system can distinguish glucose-related signals from background noise and interference, improving measurement accuracy without requiring complex filtering algorithms
Solution Approach 2:
The probing potential modulations act as an intermediary that separates the glucose measurement signal from background interference. The PPM-induced current responses serve as a mediator that carries information about both glucose concentration and sensor characteristics, allowing for accurate measurement despite the presence of background signals
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The PPM method allows for accurate, rapid, and reliable glucose concentration determination by minimizing sensor sensitivity changes and background interference, reducing warm-up time, and providing a broad scope connection from in-vitro to in-vivo measurements.
Implementation Method 1
a sensor configured to produce current signals from interstitial fluid
Data Source
AI summary
A method of determining glucose values during continuous glucose monitoring (CGM) measurements includes providing a CGM device including a sensor, a memory, and a processor; applying a constant voltage potential to the sensor; measuring a primary current signal resulting from the constant voltage potential and storing the measured primary current signal in the memory; applying a probing potential modulation sequence to the sensor; measuring probing potential modulation current signals resulting from the probing potential modulation sequence and storing measured probing potential modulation current signals in the memory; determining an initial glucose concentration based on a conversion function and a ratio of measured probing potential modulation current signals; determining a connection function value based on the primary current signal and a plurality of the probing potential modulation current signals; and determining a final glucose concentration based on the initial glucose concentration and the connection function value. Other aspects are disclosed.