Biosensor Strip Low-Profile Design for Reduced Sample Volume
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Solution Overview
Problem
Current methods for preparing biosensor strips result in a high volume of the electrochemical cell due to the formation of a dome during the lamination process, require complex and intermittent alignment procedures, and suffer from variability in sample fill rates due to adhesive flow and fine mesh usage, leading to inconsistent performance and increased pain for patients due to the amount of blood required for testing.
Innovation Solution
A biosensor strip design featuring a low-profile tape with incompressible elements, such as threads or ribbons, to create vents in the sample flow channel, allowing for continuous and accurate application of the cover layer without heat-induced damage to enzymes, and reducing the volume of the sample flow channel by removing the dome, while also ensuring reliable and reproducible filling with a liquid sample.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a profiled block is used to laminate the cover to the remaining components, then a strong bond is achieved, but a dome forms in the tape increasing the volume of the electrochemical cell
Solution Approach 1:
The adhesive is preheated before application to ensure proper flow and bonding characteristics, allowing the tape to be applied without requiring excessive pressure that would create dome formation. This preliminary preparation of the adhesive enables strong bonding without the need for a thick dome structure.
Solution Approach 2:
The temperature of the adhesive is controlled and maintained within a specific range during the lamination process. By optimizing the temperature parameter, the adhesive achieves optimal viscosity and bonding strength without requiring excessive pressure or creating a dome, thus reducing the overall volume of the electrochemical cell.
2Manufacturing precision
If intermittent lamination process is used with indexing and halting motion, then precise alignment is achieved, but production efficiency is reduced
Solution Approach 1:
The lamination process is made continuous by eliminating the need to halt and index the tape during application. The tape is fed continuously through the lamination zone, and the adhesive is applied in a continuous stream, maintaining constant motion throughout the process. This continuous operation significantly improves production efficiency while still achieving precise alignment through proper positioning of the lamination zone.
Solution Approach 2:
The indexing and halting steps are removed from the lamination process. By extracting these discrete positioning operations and replacing them with a continuous feed mechanism, the process achieves both precision (through controlled continuous motion) and high productivity (without interruptions).
3Strength
If heat is applied to reactivate adhesive during lamination, then strong bonding is achieved, but enzymes are denatured at elevated temperatures
Solution Approach 1:
The adhesive is preheated to the required temperature before the biosensor components are introduced into the lamination zone. This preliminary heating allows the adhesive to be in its optimal bonding state when the components are applied, eliminating the need for subsequent high-heat treatment that would expose the enzymes to denaturing temperatures.
Solution Approach 2:
The lamination process is completed rapidly at moderate temperatures, skipping the prolonged high-temperature exposure that would denature enzymes. By rushing through the bonding process quickly at lower temperatures, strong adhesion is achieved without compromising enzyme integrity.
4Quantity of substance
If fine mesh is used to reduce sample volume, then less blood is required, but adhesive flow causes variability in sample fill rates
Solution Approach 1:
The mesh size is optimized to a specific fine gauge that balances two competing requirements: fine enough to reduce the sample volume needed, but not so fine that it creates excessive capillary action and adhesive flow. This optimized mesh parameter allows minimal sample volume while maintaining consistent fill rates by preventing adhesive from flowing into the mesh structure.
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 reduces the volume of the sample flow channel, enhances production efficiency with continuous processing, and improves the accuracy and reliability of sample filling, minimizing the amount of blood needed for testing and maintaining enzyme integrity.
Implementation Method 1
The liquid sample enters the biosensor strip via an opening formed at one end of the slot at one end of the biosensor strip. The liquid sample reaches and traverses the reaction zone by means of the action of capillary force.
Implementation Method 2
A tape application apparatus equipped with pressure rollers can be used to apply a tape having a backing having a layer of pressure-sensitive adhesive to the uncompleted biosensor strips.
Implementation Method 3
If a pressure-sensitive adhesive, a tape application apparatus employing heat to melt or soften the adhesive would not be used. A tape application apparatus equipped with pressure rollers can be used to apply a tape having a backing having a layer of pressure-sensitive adhesive to the uncompleted biosensor strips.
Data Source
AI summary
A biosensor strip having a low profile for reducing the volume of liquid sample needed to perform an assay. In one embodiment, the biosensor strip comprises an electrode support; an electrode arrangement on said electrode support; a cover; a sample flow channel; and an incompressible element placed between said cover and said electrode support, the incompressible element providing an opening in at least one side or in the distal end of said sample flow channel to provide at least one vent in said sample flow channel. In another embodiment, the biosensor strip comprises an electrode support; an electrode arrangement on said electrode support; a cover; and a sample flow channel, the cover having a plurality of openings formed therein, at least one of the openings in register with said sample flow channel. The invention further includes methods for preparing such a biosensor strips in a continuous manner.