Biodegradable Polymer Microneedle Patch for Low-Impedance Biosensing

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Solution Overview

Problem

Conventional electrical measurement electrodes face high electrical impedance due to the stratum corneum, leading to degraded signal quality and safety concerns, particularly with rigid and non-biodegradable microneedle electrodes that are sensitive to movement and complex to manufacture.

Innovation Solution

A patch with nano-structures or micro-structures made of biocompatible, non-conductive crosslinked polymers that swell with interstitial liquid to become conductive, providing improved signal quality and safety without the need for invasive procedures or complex manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If microneedle electrodes made of rigid and non-biodegradable materials are used to pierce the stratum corneum, then measurement impedance is reduced and signal quality is improved, but the device becomes sensitive to movement and poses safety risks due to breakage

Engineering Contradiction:
Improvesignal qualityVSAvoidsafety
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the material parameters from rigid and non-biodegradable to flexible and biodegradable polymers. The microneedles are made of materials that can degrade under physiological conditions, eliminating safety risks associated with permanent foreign objects. The flexibility parameter is also modified to reduce sensitivity to movement while maintaining the ability to pierce the stratum corneum.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs disposable biodegradable microneedles that are intended for single-use and then safely degrade in the body. This eliminates the need for removal and prevents long-term safety issues, while the low cost of these temporary structures allows for optimized performance without concern for reuse.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Object-affected harmful factors

If microneedle electrodes made of rigid materials are used, then the stratum corneum can be effectively pierced, but the device becomes sensitive to parasitic movements and prone to breakage

Engineering Contradiction:
Improvestratum corneum impedanceVSAvoidmechanical robustness
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent modifies the mechanical parameters of the microneedles by using flexible materials that can bend and deform without breaking. This flexibility allows the needles to navigate tissue variations and resist breakage from movement, while still maintaining sufficient rigidity to pierce the stratum corneum effectively.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent may employ composite material structures combining different polymer components to achieve optimal balance between piercing capability and flexibility. The composite structure allows one component to provide the necessary hardness for penetration while another component provides flexibility and breakage resistance.

Inventive Principle:
Principle #40Composite materials

3Object-generated harmful factors

If porous microneedles are used for electroosmosis, then interstitial fluid extraction is enabled, but the manufacturing process becomes complex requiring multiple steps including coating and soaking

Engineering Contradiction:
Improvefluid extraction capabilityVSAvoidmanufacturing process
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs microneedles with inherent porosity built into the base polymer structure during manufacturing, eliminating the need for subsequent coating or soaking steps to create pores. The porous structure is self-generated through the manufacturing process itself, simplifying the overall fabrication sequence while maintaining fluid extraction capability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent removes the complex multi-step coating and soaking processes from the manufacturing sequence by integrating porosity directly into the base polymer material. This extraction of unnecessary steps simplifies the manufacturing process while preserving the essential fluid extraction function.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If extradermal electrodes are placed on the stratum corneum, then the placement is simple, but the high electrical impedance of the stratum corneum degrades the signal-to-noise ratio

Engineering Contradiction:
Improveplacement simplicityVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent segments the electrode structure into microneedle components that can penetrate through the stratum corneum barrier. This segmentation allows the electrode to bypass the high-impedance outer layer and establish contact with underlying tissues, achieving both simple placement and low-impedance signal acquisition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The microneedles perform preliminary mechanical action by piercing the stratum corneum before electrical measurement begins. This preliminary penetration action creates conductive pathways through the impedance barrier, enabling subsequent high-quality electrical signals without requiring complex placement procedures.

Inventive Principle:
Principle #10Preliminary action

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 patch achieves lower impedance, enhancing signal-to-noise ratio, ensuring patient safety, and simplifying use and manufacturing, while being biodegradable and resistant to movement artifacts, making it suitable for long-lasting portable sensors.

Implementation Method 1

the non-conductive crosslinked polymer swells with interstitial fluid and the patch thus becomes conductive

Methodology Applied
Scientific EffectSwelling: Absorption (physical)

Data Source

PatentEP4338670A1Electrode device, preparation method therefor and uses thereof
Publication Date: 2024.03.20 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4338670A1 patent drawingFigure 1~2
  • EP4338670A1 patent drawingFigure 3~4
  • EP4338670A1 patent drawingFigure 5~7

AI summary

The present invention relates to an electrode-type device comprising i) a patch having first and second opposing faces, said first face having nanostructures and/or microstructures, said patch, said nanostructures, and said microstructures being made of a material comprising at least one cross-linked polymer, and ii) an electrical contact re-establishment element applied to or integrated into said second face. The present invention also relates to a method for preparing such a device and its uses.