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Lateral Flow
AX-2X-S-Array
Building on the AX-2X-S, the AX-2X-S-A offers new array lateral flow capabilities for highly multiplexed and multi-analyte tests in a very low-cost test strip and cartridge.
What is lateral flow?
Lateral flow assays (LFAs), also known as immunochromatographic tests, are simple diagnostic tests utilised to confirm the presence of a target analyte in a liquid sample. LFAs are highly versatile and can detect a wide variety of targets, including proteins, nucleic acids, and small molecules.[1] Their ease of use and fast turnaround (typically providing results in 5-30 mins) make them especially valuable in point of care and field deployed settings, where complex laboratory equipment may not be available. Common examples include pregnancy tests and COVID-19 rapid antigen self tests.
Operating principles
LFAs utilise capillary action to transport a liquid sample through a test strip containing specific biochemical reagents. These test strips are composed of several key components:
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Sample Pad: Absorbs and prepares the sample for analysis, ensuring a consistent flow.
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Conjugate Pad: Contains labeled detection antibodies or probes that bind to the target analyte if present.
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Nitrocellulose Membrane: Houses the test and control lines. The test line captures the target analyte complex, while the control line verifies proper test function.
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Absorbent Pad: Wicks away excess liquid to maintain the flow and complete the assay.
When a liquid sample, such as blood, saliva, or a diluted substance, is applied to the sample pad, it flows across the strip by capillary action. When passing the conjugate pad, conjugated antibodies with colorimetric of fluorescent labels attach to target analytes. If the target analyte is present, it binds to the labelled antibody probes and is captured on the test line where, thanks to the labelled conjugate, the signal can be detected. The control line confirms that the assay has functioned correctly, regardless of the test result.
This simple, self-contained mechanism is what makes LFAs an invaluable tool for rapid diagnostics across a wide range of industries.
What is lateral flow?
Lateral flow assays (LFAs), also known as immunochromatographic tests, are simple diagnostic tests utilised to confirm the presence of a target analyte in a liquid sample. LFAs are highly versatile and can detect a wide variety of targets, including proteins, nucleic acids, and small molecules.[1] Their ease of use and fast turnaround (typically providing results in 5-30 mins) make them especially valuable in point of care and field deployed settings, where complex laboratory equipment may not be available. Common examples include pregnancy tests and COVID-19 rapid antigen self tests.
Operating principles
LFAs utilise capillary action to transport a liquid sample through a test strip containing specific biochemical reagents. These test strips are composed of several key components:
-
Sample Pad: Absorbs and prepares the sample for analysis, ensuring a consistent flow.
-
Conjugate Pad: Contains labeled detection antibodies or probes that bind to the target analyte if present.
-
Nitrocellulose Membrane: Houses the test and control lines. The test line captures the target analyte complex, while the control line verifies proper test function.
-
Absorbent Pad: Wicks away excess liquid to maintain the flow and complete the assay.
When a liquid sample, such as blood, saliva, or a diluted substance, is applied to the sample pad, it flows across the strip by capillary action. When passing the conjugate pad, conjugated antibodies with colorimetric of fluorescent labels attach to target analytes. If the target analyte is present, it binds to the labelled antibody probes and is captured on the test line where, thanks to the labelled conjugate, the signal can be detected. The control line confirms that the assay has functioned correctly, regardless of the test result.
This simple, self-contained mechanism is what makes LFAs an invaluable tool for rapid diagnostics across a wide range of industries.
Diagram showing typical lateral flow test operating principles. Reproduced with permission under CC BY. Mirica A-C, Stan D, Chelcea I-C, Mihailescu CM, Ofiteru A and Bocancia-Mateescu L-A (2022) Latest Trends in Lateral Flow Immunoassay (LFIA) Detection Labels and Conjugation Process. Front. Bioeng. Biotechnol. 10:922772. doi: 10.3389/fbioe.2022.922772
LFAs are used across a range of industries including:
Human Health
Veterinary
Agriculture
Food Safety
Environmental
Fitness
Research
Lateral Flow Readers
While lateral flow assays can be read visually, interpreting results with the human eye introduces subjectivity and variability. Lateral flow readers address this challenge by providing objective, consistent, and quantitative analysis of test results.[2] These devices use optical sensors and software technologies to detect and measure signals on the test strip, ensuring accurate and reliable outcomes.
Lateral flow readers are particularly advantageous in applications requiring high sensitivity or the quantification of results. They can analyse fluorescent signals, which often offer greater sensitivity and precision with reduced background noise compared to colorimetric assays enabling the detection of analytes with low abundance. Additionally, these readers streamline workflows by automating result capture, data analysis, and reporting.
Axxin’s AX-2X-S Lateral Flow Reader is a high-performance platform designed to elevate lateral flow testing. Featuring cutting-edge technology, the AX-2X-S delivers:
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High Sensitivity and Specificity: Ensuring accurate detection of low-abundance analytes.
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Rapid Analysis: Producing qualitative or quantitative results.
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Versatility: Supporting visual and colorimetric assays for a wide range of applications.
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Automated Workflow Management: Integrating seamlessly with laboratory and field workflows.
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Multiplexing: Capable of reading 5 lines of more per strip.
With its robust design and powerful features, the AX-2X-S is ideal for both point-of-care and laboratory environments, ensuring reliable results every time. For more details, explore the full specifications and applications on the AX-2X-S product page.
Array Lateral Flow
A new capability in lateral flow diagnostics, array lateral flow provides highly multiplexed, multianalyte assays on a single test strip. This is achieved by printing an array of target (and control) antibodies on the test strip instead of the typical lines observed in most LFAs. This allows for higher densities of antibodies without requiring additional sample. Axxin's AX-2X-S-A is specifically design to read and interpret array lateral flow assays.
[1] Nan, X., Yang, L., and Cui, Y. (2023) ‘Lateral flow immunoassay for proteins’, Clinica Chimica Acta, 544, 117337. doi: 10.1016/j.cca.2023.117337015112.
[2] Park, J. (2022) ‘Lateral Flow Immunoassay Reader Technologies for Quantitative Point-of-Care Testing’, Sensors, 22(19):7398. doi: 10.3390/s22197398.