Flexible Glucose Sensor Stack for Low-Pain Continuous Monitoring

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Solution Overview

Problem

Current glucose monitoring sensors are painful to insert, require frequent calibration with painful finger-sticks, and have limitations in long-term durability and cost-effectiveness for continuous glucose monitoring in diabetic patients.

Innovation Solution

A planar flexible analyte sensor with a platinum-sputtered layer on a polyester substrate, incorporating an insulating dielectric layer, glucose oxidase, and a glucose limiting membrane, fabricated using a roll-to-roll process to reduce production costs and enhance sensor accuracy and longevity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If subcutaneously implanted sensors are used for continuous glucose monitoring, then continuous monitoring capability is improved, but insertion pain and risk of infection increase

Engineering Contradiction:
Improvecontinuous monitoring capabilityVSAvoidinsertion pain and infection risk
Core Design Contradiction:
Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent employs a flexible planar sensor design with thin film structures that can be inserted into subcutaneous tissue with minimal trauma. The flexible base layer and thin electrochemical sensing stack allow the sensor to conform to tissue contours, reducing insertion pain and improving patient comfort while maintaining continuous monitoring capability.

Inventive Principle:
Principle #30Flexible shells and thin films

2Measurement precision

If traditional meters and test strips are used for blood glucose monitoring, then measurement capability is provided, but frequent painful finger-sticks are required

Engineering Contradiction:
Improveblood glucose measurementVSAvoidpain from finger-sticks
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the measurement function from the painful finger-stick procedure by implementing a continuous glucose sensor that measures glucose levels in interstitial fluid through a minimally invasive subcutaneous insertion. This eliminates the need for repeated punctures of the finger while maintaining measurement capability through continuous monitoring of glucose in the interstitial fluid.

Inventive Principle:
Principle #2Taking out (Extraction)

3Duration of action of moving object

If currently available continuous monitoring devices are used, then continuous glucose data is obtained, but frequent calibration with finger-sticks is required

Engineering Contradiction:
Improvecontinuous monitoring durationVSAvoidtime for calibration
Core Design Contradiction:
Duration of action of moving objectVSLoss of time

Solution Approach 1:

The patent implements factory calibration of the electrochemical sensor during the manufacturing process, establishing a known relationship between the sensor signal and glucose concentration. This self-calibrating approach eliminates the need for frequent post-deployment calibration procedures, allowing the sensor to maintain accurate continuous monitoring without requiring additional patient time for calibration finger-sticks.

Inventive Principle:
Principle #25Self-service

4Ease of manufacture

If roll-to-roll fabrication process is used for sensor production, then production cost is reduced, but manufacturing precision may be affected

Engineering Contradiction:
Improveproduction costVSAvoidsensor fabrication precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent segments the sensor fabrication into discrete sequential steps including substrate preparation, electrode deposition, enzyme layer application, and membrane formation. Each step is optimized for roll-to-roll processing while maintaining precision through controlled deposition parameters and quality assurance measures at each stage, enabling cost-effective high-volume production without sacrificing sensor performance.

Inventive Principle:
Principle #1Segmentation

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 solution provides improved accuracy and reduced pain during use, along with longer sensor lifespan and lower production costs, addressing the limitations of traditional glucose monitoring systems.

Implementation Method 1

a first electrode formed from a layer of sputtered platinum on the base layer

Methodology Applied
Scientific EffectSputtering: Sputtering

Implementation Method 2

the glucose oxidase is used to catalyze the reaction between glucose and oxygen to yield gluconic acid and hydrogen peroxide (H 2 O 2 ). The hydrogen peroxide reacts electrochemically

Methodology Applied
Scientific EffectElectrochemical reaction: Redox Reactions

Implementation Method 3

the glucose oxidase is used to catalyze the reaction between glucose and oxygen

Methodology Applied
Scientific EffectEnzyme catalysis: Enzyme

Implementation Method 4

the glucose oxidase is used to catalyze the reaction between glucose and oxygen to yield gluconic acid and hydrogen peroxide

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 5

an insulating dielectric layer over the base layer, wherein the insulating dielectric layer leaves a portion of the first electrode exposed

Methodology Applied
Scientific EffectDielectric insulation: Dielectric

Implementation Method 6

a glucose limiting membrane over the glucose oxidase layer

Methodology Applied
Scientific EffectSelective permeation: Semipermeable Membrane

Data Source

PatentEP3621521B1Analyte sensors and methods for fabricating analyte sensors
Publication Date: 2024.09.25 MEDTRONIC MINIMED INC
  • EP3621521B1 patent drawingFigure 1~3
  • EP3621521B1 patent drawingFigure 4
  • EP3621521B1 patent drawingFigure 5~6

AI summary

Analyte sensors and methods for fabricating analyte sensors are provided. In an exemplary embodiment, a planar flexible analyte sensor includes a flexible base layer and a first electrode formed from a layer of sputtered platinum on the base layer. Also, the analyte sensor includes an insulating dielectric layer over the base layer, wherein the insulating dielectric layer leaves a portion of the first electrode exposed. Further, the analyte sensor includes an electrochemical sensing stack over the exposed portion of the first electrode, including a glucose oxidase layer over the layer of sputtered platinum and a glucose limiting membrane over the glucose oxidase layer.