Block Copolymer Diffusion Layer for Stable In-Vivo Enzymatic Sensors
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Solution Overview
Problem
Existing electrode systems for in-vivo analyte measurement face challenges in the preparation and application of diffusion barriers due to the use of polymer or copolymer mixtures, which can lead to precipitation and solubility issues, particularly when charged polymers are involved, making the manufacturing process tedious and prone to workability problems.
Innovation Solution
A diffusion barrier comprising a block copolymer with a specific composition of 75 to 95 mol-% hydrophilic block and 5 to 25 mol-% hydrophobic block, covalently linked, is used to control analyte diffusion, offering improved physico-chemical characteristics and ease of manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer or copolymer mixtures are used to form the diffusion barrier, then the desired diffusion control and permeability characteristics can be achieved, but the preparation process becomes tedious and problematic due to precipitation and solubility issues
Solution Approach 1:
The patent combines multiple polymer functions into a single block copolymer molecule, where hydrophilic blocks and hydrophobic blocks are covalently linked. This eliminates the need to mix separate polymer solutions, resolving the precipitation and solubility problems while maintaining the desired diffusion control characteristics.
Solution Approach 2:
The block copolymer acts as a composite material at the molecular level, integrating hydrophilic and hydrophobic segments into one structure. This provides both the permeability characteristics of hydrophilic polymers and the mechanical stability of hydrophobic polymers without the workability issues of mixing separate polymers.
2Reliability
If ionic polymers are included in the diffusion barrier mixture, then electrostatic interactions and analyte selectivity can be enhanced, but solubility problems arise making it difficult to find a suitable solvent
Solution Approach 1:
The patent merges ionic and non-ionic polymer characteristics into a single block copolymer structure. The ionic blocks provide electrostatic interactions for analyte selectivity, while the non-ionic blocks ensure solubility in common solvents, eliminating the need to separately dissolve and mix ionic and non-ionic polymers.
3Reliability
If the diffusion barrier is made from block copolymer with high hydrophilic content, then analyte permeability is improved, but mechanical stability and structural integrity are reduced
Solution Approach 1:
The block copolymer creates a molecular-level composite where hydrophilic blocks (75-95 mol-%) provide analyte permeability pathways while hydrophobic blocks (5-25 mol-%) provide mechanical stability and structural integrity, achieving both high permeability and adequate strength.
Solution Approach 2:
Different blocks of the copolymer perform different functions: hydrophilic blocks create permeable regions for analyte transport, while hydrophobic blocks form structural regions providing mechanical stability. This local differentiation of properties within the single polymer material resolves the contradiction between permeability and strength.
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 block copolymer diffusion barrier provides excellent permeability, mechanical flexibility, and stability, allowing for the production of small, flexible sensors with reduced sensor drift and efficient analyte transfer, suitable for both short-term and long-term in-vivo applications.
Implementation Method 1
a diffusion barrier that controls diffusion of the analyte from body fluid surrounding the electrode system to the enzyme molecules
Implementation Method 2
The block copolymer comprises from 75 to 95 mol-% of at least one hydrophilic block and from 5 to 25 mol-% of at least one hydrophobic block, based on the total amount (mol) of the block copolymer in the dry state
Data Source
AI summary
The present disclosure relates to an electrode system for measuring the concentration of an analyte under in-vivo conditions, comprising an electrode with immobilized enzyme molecules and a diffusion barrier that controls diffusion of the analyte from body fluid surrounding the electrode system to the enzyme molecules.