Separation Membrane Lateral Flow Assay for Raw Blood Samples
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Solution Overview
Problem
Conventional lateral flow devices face issues with clogging and interference from confounding components in raw fluid samples, particularly whole blood, leading to inaccurate test results due to obstructed flow and optical interference, necessitating time-consuming preprocessing that is impractical for point-of-care settings.
Innovation Solution
A lateral flow assay device with a separation membrane that retains confounding components, allowing unprocessed fluid samples to flow directly to a detection zone, using a first flow path for particles and a second flow path for analytes, with a buffer to direct samples to a capture zone where immobilized capture agents bind the analytes, enhancing detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a raw fluid sample is applied directly to the assay membrane, then the test can be performed without preprocessing, but the assay membrane becomes clogged and flow is obstructed
Solution Approach 1:
The device is divided into two distinct flow paths: a first flow path for unprocessed samples that separates particles, and a second flow path for processed samples that maintains laminar flow. This segmentation allows the assay membrane to receive pre-separated samples, preventing clogging while maintaining operational simplicity.
Solution Approach 2:
A separation membrane is introduced as an intermediary component between the sample application zone and the assay membrane. This separation membrane filters out particles and confounding components from the raw sample before it reaches the assay membrane, preventing clogging while allowing the assay to remain simple and rapid.
2Measurement precision
If confounding components are removed from the sample, then detection accuracy is improved, but the device complexity increases
Solution Approach 1:
A separation membrane serves as an intermediary filtering component that removes confounding components (particles, cells, debris) from the sample before it reaches the detection zone. This simple filtration mechanism improves detection accuracy by eliminating optical interference and flow obstruction without requiring complex processing systems.
Solution Approach 2:
The separation membrane is strategically positioned only at the sample entry point where particle separation is most critical, rather than implementing complex filtration throughout the entire device. This localized approach improves detection accuracy while minimizing added device complexity.
3Measurement precision
If sample preprocessing is performed to remove confounding components, then accurate detection is achieved, but time is lost and productivity decreases
Solution Approach 1:
The separation membrane performs preliminary separation of particles and confounding components from the sample before it reaches the detection zone. This pre-action eliminates the need for time-consuming manual preprocessing steps (centrifugation, filtration) while maintaining detection accuracy, thereby increasing productivity.
Solution Approach 2:
The device performs its own sample preparation automatically through the separation membrane as sample flows through it. This self-service mechanism eliminates the need for external preprocessing equipment and manual intervention, enabling rapid testing while maintaining accurate detection of analytes in complex samples.
4Reliability
If particles are retained in the separation membrane, then flow obstruction is prevented, but the membrane requires compression to maintain separation
Solution Approach 1:
Compression structures are applied locally only to the separation membrane area where particle retention is critical, rather than compressing the entire device. This localized compression maintains effective particle separation and prevents flow obstruction through the separation membrane while minimizing overall device complexity and stress requirements.
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 enables accurate detection of analytes in unprocessed samples without preprocessing, reducing the need for large sample volumes and improving sensitivity by retaining confounding components, allowing for precise quantification of analytes even at varying concentrations without dilution.
Implementation Method 1
a separation membrane configured to retain particles in the fluid sample
Implementation Method 2
The sample receiving zone includes a conjugate including a label and an agent configured to specifically bind to the analyte of interest
Implementation Method 3
The capture zone includes an immobilized capture agent specific to the analyte of interest
Implementation Method 4
a buffer that directs the fluid sample received through the bottom surface of the membrane along the flow path to the capture zone
Data Source
AI summary
Lateral flow assay devices, systems, and methods described herein separate components of a fluid sample, including small volume, undiluted, unprocessed samples. In one aspect, components are retained in a separation membrane that is spatially above and in fluid communication with a conjugate pad of a lateral flow assay. Devices, systems, and methods described herein can retain particles from a fluid sample that obstruct flow of the fluid sample through the conjugate pad to a detection zone and/or interfere with detection of an analyte of interest in the detection zone.