Hydrogel Microneedle Patch With Isolated Bioelectrode for Glucose Sensing
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Solution Overview
Problem
Existing microneedle-based biosensors for transdermal glucose monitoring face challenges such as invasive needle length, limited sensor lifespan and accuracy, cytotoxicity, delamination of bioelectrode materials, complex and costly manufacturing processes, and issues with electrode adhesion and latency in ISF extraction.
Innovation Solution
A microneedle patch with a cross-linked, biocompatible hydrogel support and integrated porous bioelectrode that swells upon contact with ISF, providing electrolytic conductivity and minimizing direct tissue contact, ensuring adhesion and rapid analyte detection without toxicity risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional needles are used for glucose monitoring, then glucose detection is achieved, but patient comfort deteriorates due to invasive needle length
Solution Approach 1:
The device segments the needle into microneedles with length of 20-2000 μm, dividing the single invasive needle into multiple tiny needles that penetrate the skin barrier without reaching nerve-rich layers, thus maintaining glucose detection capability while eliminating patient discomfort
Solution Approach 2:
The microneedles are made porous to enable interstitial fluid uptake through capillary action, allowing glucose detection without requiring deep penetration into the skin, thereby reducing needle length and improving patient comfort
2Measurement precision
If solid-state microsensors with direct electrode-tissue contact are used, then electrochemical detection is achieved, but cytotoxicity and stability issues arise
Solution Approach 1:
The patent introduces an intermediary layer between the electrode and tissue that enables electrochemical detection while preventing direct toxic contact, thus maintaining measurement precision while reducing cytotoxicity
Solution Approach 2:
Porous structures are used to create an intermediary zone that allows fluid and analyte transport while physically separating the electrode from direct tissue contact, reducing cytotoxic effects
3Ease of manufacture
If bioelectrode materials are deposited on external surface of microneedles, then sensor integration is achieved, but delamination during insertion occurs
Solution Approach 1:
The bioelectrode materials are nested within the microneedle structure rather than deposited on the external surface, preventing delamination during insertion while maintaining sensor integration and manufacturability
Solution Approach 2:
The porous microneedle structure allows bioelectrode materials to be embedded within the matrix, providing mechanical interlocking that prevents delamination during insertion while maintaining ease of manufacture
4Adaptability or versatility
If hollow microneedles are used for fluid extraction, then flexibility in bioelectrode incorporation is improved, but penetration efficiency deteriorates
Solution Approach 1:
The patent uses composite microneedle structures that combine the mechanical strength needed for efficient penetration with the flexibility to incorporate various bioelectrode materials, resolving the contradiction between penetration efficiency and adaptability
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 device achieves minimally invasive, rapid, and accurate transdermal detection of biomarkers with enhanced sensor stability and compatibility with various bioelectrodes, eliminating delamination and toxicity risks.
Implementation Method 1
the microneedles (3) and at least the contact surface of said support (1) with said skin (2) are formed of a cross-linked, biocompatible hydrogel, which is electronically non-conductive in the dry state and electrolytically conductive in contact with an aqueous fluid
Implementation Method 2
under conditions conducive to the swelling of said cross-linked hydrogel constituting the microneedles (3) by this fluid
Implementation Method 3
at least one porous bioelectrode (10), optionally nano- or micro-structured, and comprising at least one biologically active species, in particular an enzyme, immobilized on the surface of a conductive material
Implementation Method 4
MN patches are arrays of micrometer-sized needles, typically ranging in height from 20 to 2000 μm, that are specifically designed to penetrate the skin barrier to reach the dermis layer
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a device for transdermal electrochemical measurements comprising at least one polymeric support having a surface dedicated to contact with skin, at least one array of polymeric microneedles attached to said support and extending outwards from said surface of the support, and at least one porous and/or nano/micro structured bioelectrode, and comprising at least one biologically active species immobilized on the surface of a conductive material, characterized in that said microneedles and at least the contact surface of said support with said skin are formed of a cross-linked, biocompatible hydrogel, which is non-electronically conductive in the dry state and electrolytically conductive in contact with an aqueous fluid, and in that said bioelectrode is disposed in contact with the hydrogel and is devoid of direct contact with the skin. The invention also relates to a method for preparing said device and some of its uses.