Rough Membrane Carrier for POCT Sensitivity
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Solution Overview
Problem
Current Point of Care Testing (POCT) reagents face challenges in detection sensitivity due to variations in liquid sample flow rates through nitrocellulose membranes, leading to potential false negatives before substance binding occurs.
Innovation Solution
A membrane carrier with a rough structure having protrusions and a specific roughness curve profile, coated with a silane coupling agent and potentially a cross-linking agent, is used to enhance detection sensitivity by optimizing the flow channel's microstructure and surface chemistry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a nitrocellulose membrane is used as a membrane carrier, then the liquid sample can move through the membrane by capillary force, but the hole diameter and connection方式 are not uniform causing variation in flow rates
Solution Approach 1:
The patent uses a porous polyethylene terephthalate (PET) membrane as the membrane carrier, replacing the traditional nitrocellulose membrane. The porous structure allows liquid sample movement through capillary forces while providing more uniform pore distribution and dimensions, thereby reducing flow rate variations between different membranes.
Solution Approach 2:
The patent changes the material parameter from nitrocellulose to porous PET, and controls the pore size parameter to be 0.03-10 μm with specific uniformity requirements. This parameter change and control approach resolves the contradiction by providing both capillary action capability and manufacturing precision.
2Loss of time
If the flow rate of liquid sample varies between membranes, then the detection time changes, but this causes erroneous determination of substance detection
Solution Approach 1:
The uniform porous structure of the PET membrane ensures consistent capillary forces across different membranes, leading to uniform liquid sample flow rates and detection times, thereby eliminating erroneous negative results.
Solution Approach 2:
The patent applies preliminary surface treatment to the PET membrane, including plasma treatment and coating with detection substances, to ensure that the membrane is properly prepared before use. This preliminary action ensures consistent detection performance across different membranes and eliminates variability in detection results.
3Manufacturing precision
If a synthetic material is used to prepare the membrane carrier, then the structure can be made uniform, but the affinity between detection substance and material needs to be increased through surface treatments
Solution Approach 1:
The porous PET membrane provides a uniform structure with controlled pore sizes, and the porous nature inherently increases the surface area available for detection substance attachment, reducing the need for complex surface treatments compared to non-porous synthetic materials.
Solution Approach 2:
The patent uses a composite approach by combining the PET base material with various detection substances and coating materials. This composite structure provides both the uniform porous framework and the necessary affinity for detection substances, simplifying the overall manufacturing process.
4Measurement precision
If the affinity between detection substance and synthetic material is improved through surface treatments, then detection sensitivity increases, but the manufacturing process becomes more complex
Solution Approach 1:
The porous structure of the PET membrane naturally provides high surface area to volume ratio, which enhances the loading capacity of detection substances without requiring extensive surface treatment processes, thus improving detection sensitivity while maintaining manufacturing simplicity.
Solution Approach 2:
The patent performs preliminary surface treatments such as plasma treatment and detection substance coating during the membrane manufacturing process itself, rather than as separate post-processing steps. This integration reduces overall device complexity while achieving high detection sensitivity.
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 membrane carrier design improves detection sensitivity by increasing the amount of detection substance carried in the detection zone, reducing false negatives and enhancing the accuracy of substance detection in POCT kits.
Implementation Method 1
the microstructure that generates a capillary action for transporting the liquid sample is provided on a bottom surface of the flow channel
Implementation Method 2
it is necessary to increase the affinity between the detection substance and the material in order to improve the detection sensitivity, and it is considered effective to perform various surface treatments on the material in advance
Data Source
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Figure 3(a)~3(b)
AI summary
Provided is a membrane carrier for a test kit for detecting a substance to be detected in a liquid sample, the membrane carrier including: a flow channel having a detection zone, in which the flow channel has a rough structure A having protrusions, at least in the detection zone, a rough microstructure B is formed on a surface of the protrusion, a silane coupling agent is attached to a surface of the rough microstructure B, and a maximum peak height Rp of a roughness curve of a protrusion at which the rough microstructure B is formed, as measured according to JIS B0601: 2013 using a three-dimensional roughness analysis scanning electron microscope, is equal to or more than 0.005 µm and equal to or less than 10 µm, and an average length RSm of a roughness curve element is equal to or more than 0.01 µm and equal to or less than 15 µm.