German-Engineered Nitrocellulose Membranes Bring Consistency to Lateral Flow Assay Tests
Many industries use lateral flow tests to detect a range of molecules, including biomarkers, pathogens and environmental contaminants. Fast time-to-data makes them especially useful as a point-of-care diagnostic and as a public health tool sold directly to consumers. In this blog, we talk about the nitrocellulose membranes that form the backbone of these tests.
This article is posted on our Science Snippets Blog
What is a lateral flow assay?
Lateral flow assays are portable, easy-to-use in vitro medical devices designed to detect a specific analyte in a complex sample like saliva. Popular examples are home pregnancy tests and, most recently, SARS-CoV-2 rapid antigen tests. The main structural components of a lateral flow assay test are:
- Sample pad – Sample is applied here
- Conjugate pad – Conjugate molecules are immobilized here to interact with analyte as the sample migrates through the strip
- Nitrocellulose membrane – Holds the bioassay molecules of the test and control lines and serves as the reaction site for the lateral flow immunoassay
- Absorbent pad – Excess reagent is held here
The Role of Nitrocellulose Membrane in a Lateral Flow Test
Nitrocellulose membrane plays a critical role in a lateral flow test. First, it acts as the main motor of the test, drawing samples and conjugates from one end of the strip to the other. Second, it houses reagents in the test and control lines, which capture the sample-conjugate complex as it passes through.
In addition to the affinities of the immunoassay components, the capillary speed and surface quality of the nitrocellulose membrane are also crucial parameters for a sensitive test that produces sharp lines.
Sourcing the Best Nitrocellulose Membrane
Manufacturers of lateral flow tests need to consider many factors when choosing a supplier for nitrocellulose membrane:
- Performance: High-protein binding and smooth flow of liquid in all directions
- Consistency: High-quality, consistent performance from lot to lot
- Availability: Reliable supply of membrane for large-scale ordering
- Traceability: Full documentation to meet local regulations
- Reputation: Expertise in membrane technology and manufacturing
- All raw materials are REACH compliant
Go With the Industry Leader in Membrane Technology
When selecting suppliers, developers and manufacturers of lateral flow assays , look for in-depth expertise in nitrocellulose membrane manufacturing and related industrial applications. Sartorius has a long legacy in this field as a supplier of high-quality nitrocellulose membranes to diagnostic and life science markets. In fact, Sartorius was the site of the very first industrially manufactured nitrocellulose membranes in 1960. Today, these innovative manufacturing practices continue to evolve in a state-of-the-art facility in Germany.
Nitrocellulose Membranes Designed for Lateral Flow Tests
Sartorius UniSart® CN nitrocellulose membranes are well known not only as a key component of high-performing rapid tests, but also for improving outcomes in every production step, including laminating, dispensing, drying, blocking, assembling and packaging. The smooth, defect-free membrane surface allows for sharp test and control lines, while the large porous structure is engineered for consistent lateral wicking of samples and reagents.
There are different membrane specifications to choose from depending on the application. The new Unisart® CN 180 DX is designed for very sensitive applications that need high protein binding and sensitivity. This membrane has slower capillary speed and higher binding capacity for detecting smaller, or lower concentration analytes. Learn about the complete UniSart® CN nitrocellulose membrane portfolio for lateral flow test manufacturing.
