Implantable Glucose Sensor Lead Assembly for Stable Long-Term Monitoring
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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 readings and short sensor life.
Innovation Solution
An enzymatic electrochemical glucose sensor is designed with a flexible lead assembly and optimized electrode configuration, submerged in a fluid-filled lumen, to maintain a high signal-to-noise ratio and reduce enzyme decay, allowing continuous operation for up to two years without recharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the surface area and volume of the sensing element are reduced to prevent insertion pain and wearer discomfort, then user comfort is improved, but the amount of glucose sensing agent that can be incorporated is limited, leading to sensor output continuously diminishing over time
Solution Approach 1:
The patent changes the physical and chemical parameters of the sensing element, including using a flexible substrate with optimized porosity and incorporating specific enzyme concentrations. The membrane thickness and pore size are carefully controlled to maintain both small sensor size for comfort and sufficient enzyme loading for stable long-term operation.
2Measurement precision
If the surface area of the sensing element is increased to increase the sensor current level, then signal-to-noise ratio is improved, but sensor size and volume increase, introducing pain and/or discomfort to the user
Solution Approach 1:
The patent employs a porous membrane structure that increases the effective surface area available for enzyme incorporation without proportionally increasing the external dimensions of the sensor. The porous structure allows high enzyme loading density while maintaining a compact form factor that minimizes insertion pain and wearer discomfort.
3Quantity of substance
If the membrane thickness is increased to accommodate more glucose oxidase, then enzyme concentration is increased, but diffusion delays occur resulting in a clinically unacceptable lag time in measured glucose
Solution Approach 1:
The patent uses a porous membrane with optimized pore size and distribution that allows rapid glucose diffusion while providing sufficient surface area and volume for high enzyme concentration. The porous structure creates short diffusion pathways through the membrane, maintaining clinically acceptable response times even with increased enzyme loading.
Solution Approach 2:
The patent employs a composite membrane structure combining multiple materials with complementary properties. The composite structure provides both high enzyme loading capacity and optimized mass transport characteristics, achieving fast diffusion rates while maintaining high glucose oxidase concentration for stable signal output.
4Ease of operation
If conventional sensors are used with limited surface area and volume, then insertion pain and wearer discomfort are reduced, but the sensor life is short due to enzyme degradation and foreign body response
Solution Approach 1:
The patent optimizes multiple parameters including membrane porosity, enzyme concentration, and substrate flexibility to create a sensing element that minimizes foreign body response while maintaining sufficient enzyme quantity for long-term operation. These parameter optimizations enable both comfort and extended sensor life.
Solution Approach 2:
The patent uses composite materials for the membrane and substrate that provide biocompatibility, mechanical flexibility, and controlled mass transport properties. The composite structure protects the enzyme layer from degradation while maintaining a small, comfortable form factor, thereby extending sensor operational life.
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 stable glucose level monitoring with a decay rate of less than 40% over a year and a time delay of less than 2 minutes, ensuring accurate and consistent glucose level detection over an extended period.
Implementation Method 1
The glucose oxidation reaction is a well-established metric that is used in glucose monitoring
Implementation Method 2
an enzymatic electrochemical glucose sensor... configured to generate a current... wherein the current is indicative of the glucose level
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.