Lateral Flow Sampling Channel for Low-Volume Blood Testing
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Solution Overview
Problem
Conventional lateral flow immunoassays (LFAs) require a large volume of whole blood, often exceeding 70 μL, causing discomfort and adding complexity with the need for precise measurement and dilution, which is not suitable for point-of-care testing.
Innovation Solution
A lateral flow immunoassay device with a sampling channel and diluent reservoir sealed by a removable seal, allowing controlled sampling of a predetermined volume (1-15 μL) of biomarker, which is released onto a test strip after seal removal, ensuring accurate and comfortable sampling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional LFAs require large blood volume (>70 μL) to saturate the test, then sufficient flow volume is achieved, but patient discomfort increases and sampling complexity increases
Solution Approach 1:
The device pre-fills a sampling channel with a predetermined small volume of blood (1-15 μL) before the test is performed. This preliminary action eliminates the need for large blood volumes during actual testing, reducing patient discomfort while ensuring sufficient fluid for the assay.
Solution Approach 2:
A buffer fluid is introduced as an intermediary substance that mixes with the small blood sample in the sampling channel. This buffer diluent enables the small blood volume to produce sufficient flow through the test strip, allowing adequate saturation without requiring large initial blood volumes from the patient.
2Quantity of substance
If conventional LFAs use large blood volume, then sufficient flow volume is achieved, but device complexity increases due to need for precise measurement and dilution
Solution Approach 1:
The sampling channel is pre-configured with a predetermined volume capacity (1-15 μL) during device manufacturing. This preliminary action eliminates the need for complex measurement and dilution procedures during use, as the device automatically provides the correct sample volume and buffer ratio.
Solution Approach 2:
The sampling channel and buffer reservoir are merged into a single integrated system where both the blood sample and buffer fluid are contained and mixed within the same device structure. This merging simplifies the overall process by combining sampling, dilution, and mixing functions into one automated system.
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
Enables efficient, controlled sampling of a precise biomarker volume without discomfort, facilitating point-of-care testing by minimizing blood volume requirements and simplifying the process.
Implementation Method 1
Typical LFA comprise a series of capillary beds having the capacity to transport fluid (e.g. a biomarker such as blood, saliva or urine) spontaneously
Implementation Method 2
the sample fluid migrates to a second capillary bed in the form of a conjugate pad... The analyte binds to the particles while migrating further through a third capillary bed
Implementation Method 3
A first capillary bed comprises a sample pad acting as a sponge to hold an excess of sample fluid
Data Source
AI summary
A lateral flow immunoassay device includes a porous test strip, a sampling channel having an inlet at a first end to receive a biomarker and an outlet at a second end, opposite the first end, the outlet communicating with the test strip. The sampling channel has an air vent opening at or adjacent the second end thereof, and a diluent reservoir having an outlet communicating with the test strip. The outlet of the sampling channel and the outlet of the diluent reservoir are sealed by a common removable seal to prevent communication between the sampling channel and the test strip, and the diluent reservoir and the test strip, until the seal is removed.