Implantable Glucose Sensor Design for Minimal Surface Obstruction
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Solution Overview
Problem
Conventional glucose sensors face challenges in maintaining a high signal-to-noise ratio and long-term operation due to limited surface area and volume, enzyme degradation, and foreign body response, leading to inaccurate glucose measurements and short sensor life.
Innovation Solution
An enzymatic electrochemical glucose sensor is designed with a flexible lead assembly and electronics system that generates current with minimal surface obstruction, maintaining a high signal-to-noise ratio and operating for up to two years without recharging, by optimizing electrode surface area, membrane thickness, and enzyme concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the surface area and volume of the sensing element are reduced to minimize insertion pain and foreign body response, then user comfort and biocompatibility are improved, but the amount of glucose sensing agent that can be incorporated is limited, leading to sensor output diminishment over time
Solution Approach 1:
The patent changes the physical and chemical parameters of the sensing element, including using a flexible lead assembly with optimized surface area, adjusting membrane thickness, and modifying enzyme concentration to achieve stable sensor output over two years while maintaining minimal foreign body response
Solution Approach 2:
The sensing element employs composite materials including a flexible lead assembly, selective membrane layers, and enzyme-conjugated surfaces that work together to provide both biocompatibility and long-term measurement stability
2Duration of action of stationary object
If the surface area of the sensing element is increased to incorporate more glucose sensing agent and extend sensor life, then sensor longevity is improved, but the sensor mass and volume increase, creating user discomfort and exacerbating foreign body response
Solution Approach 1:
The patent optimizes the surface area parameter of the sensing element to achieve the minimum effective area required for long-term operation while preventing excessive foreign body response, balancing sensor longevity with user comfort
Solution Approach 2:
The sensing element concentrates the glucose sensing function in a localized area with optimized surface properties, allowing sufficient enzyme loading for extended life without increasing overall sensor dimensions that would cause discomfort
3Duration of action of stationary object
If the membrane thickness is increased to accommodate more glucose oxidase enzyme, then enzyme concentration and sensor longevity are improved, but diffusion delays increase, resulting in clinically unacceptable lag time in measured glucose
Solution Approach 1:
The patent optimizes the membrane thickness parameter to achieve the optimal balance between enzyme loading capacity and glucose diffusion rate, ensuring both long-term operation and clinically acceptable response time
Solution Approach 2:
The membrane employs a porous structure that increases the effective surface area for enzyme loading while maintaining thin overall thickness, allowing sufficient glucose oxidase concentration without creating diffusion barriers that would cause lag time
4Measurement precision
If the surface area of the sensing element is increased to increase sensor current level and overcome signal-to-noise ratio limitations, then measurement precision is improved, but the need to limit sensor size and volume is compromised, introducing pain and discomfort to the user
Solution Approach 1:
The patent optimizes the surface area parameter to achieve sufficient sensor current level and signal-to-noise ratio for accurate measurement while maintaining a size that does not cause user pain or discomfort during implantation and wear
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 sensor provides accurate glucose level monitoring with a high signal-to-noise ratio and extended operation, overcoming limitations of conventional sensors by maximizing surface area and enzyme longevity while minimizing physical discomfort.
Implementation Method 1
The sensor includes an enzyme layer comprising glucose oxidase
Implementation Method 2
The glucose oxidation reaction is a well-established metric that is used in glucose monitoring
Implementation Method 3
The at least one electrode is configured to generate a current... wherein the current is indicative of the glucose level of the biological host
Implementation Method 4
which are necessary to support proper and sufficient diffusion of glucose and oxygen into the sensing element
Data Source
AI summary
A device for continuously monitoring glucose levels in a patient includes a lead assembly in electrical communication with an electronics assembly. The electronics assembly is configured to be positioned in the subcutaneous tissue and the lead assembly is configured to be positioned in a vessel of the patient, such as in a vein or in an epidural space. The lead assembly has a lumen, and includes at least one electrode in electrical communication with the electronics assembly.