Optical Stabilizing Additives for Implantable Sensor Polymer Grafts

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Solution Overview

Problem

Implantable sensors face errors in analyte readings due to variations in the opacity of the polymer graft over time, which can be caused by changes in the sensing medium, leading to unreliable longevity and accuracy.

Innovation Solution

Incorporating optical signal stabilizing additives such as titanium dioxide, barium sulfate, or hollow beads into the polymer graft to maintain its opacity over time, ensuring consistent light transmission and reducing errors in analyte measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensor uses a polymer graft for analyte sensing, then the sensor can detect analyte concentrations, but the opacity of the graft varies over time causing errors in readings

Engineering Contradiction:

Improveanalyte reading accuracyVSAvoidgraft opacity stability

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent incorporates optical stabilizing agents (such as titanium dioxide, barium sulfate, or hollow beads) into the polymer graft matrix to create a composite material. This composite structure maintains the sensing functionality of the polymer graft while the embedded optical agents stabilize the opacity by scattering light consistently, preventing the opacity variations that cause measurement errors.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The optical stabilizing agents act as intermediary particles within the polymer graft that mediate the interaction between light and the graft matrix. These particles scatter light in a controlled manner, serving as a buffer that prevents direct optical path variations caused by graft swelling or shrinking, thereby stabilizing the optical signal for accurate analyte detection.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Duration of action of moving object

If the sensor operates for extended periods in the body, then continuous monitoring is achieved, but the opacity changes over time reducing reliable longevity

Engineering Contradiction:

Improvesensor operational durationVSAvoidreading reliability over time

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

By creating a composite polymer graft containing optical stabilizing agents, the sensor maintains consistent light scattering properties throughout its operational life. The embedded particles prevent opacity drift that would otherwise occur during extended in vivo use, enabling reliable continuous monitoring over several months.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The optical stabilizing agents are incorporated into the polymer graft during manufacturing, providing preemptive stabilization against future opacity changes. This prior cushioning approach prevents reliability degradation before it occurs, ensuring consistent performance throughout the extended operational period.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Illumination intensity

If the graft becomes more clear over time, then light transmission increases, but less fluorescence light is reflected onto photodetectors reducing signal quality

Engineering Contradiction:

Improvelight transmission through graftVSAvoidfluorescence signal detection

Core Design Contradiction:

Illumination intensityVSMeasurement precision

Solution Approach 1:

The composite polymer graft with embedded optical stabilizing agents maintains consistent light scattering properties that ensure adequate fluorescence signal reflection onto photodetectors regardless of changes in overall graft clarity. The particles provide stable optical pathways that preserve signal quality even as the graft matrix undergoes temporal changes.

Inventive Principle:

Principle #40Composite materials

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 use of optical signal stabilizing additives maintains the opacity of the polymer graft, reducing errors in analyte readings and extending the sensor's reliable operation for several months without significant changes in light transmission, thereby enhancing the sensor's longevity and accuracy.

Implementation Method 1

Methodology Applied

Scientific EffectLight scattering: Scattering

Implementation Method 2

fluorescent indicator molecules may reversibly bind glucose and, when irradiated with excitation light (e.g., light having a wavelength of approximately 378 nm), emit an amount of light (e.g., light in the range of 400 to 500 nm)

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 3

A light source (e.g., light emitting diode (LED)) may emit the excitation light, which may then be absorbed by the indicator molecules in the polymer graft. A portion of the absorbed excitation light may be reflected from the polymer graft back into the sensor

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS11793430B2Use of additives, copolymers, and dopants for optical stability of analyte sensing components

Publication Date: 2023.10.24 SENSEONICS INC

AI summary

A sensor (e.g., an optical sensor) that may be implanted within a living animal (e.g., a human) and may be used to measure an analyte (e.g., glucose or oxygen) in a medium (e.g., interstitial fluid, blood, or intraperitoneal fluid) within the animal. The sensor may include a sensor substrate, electrode or housing, an analyte indicator covering at least a portion of the sensor, and one or more optical signal stabilizing additives in an environment of the sensor.