Nitrocellulose is the globally preferred membrane substrate in diagnostic lateral flow assays where antigen-antibody binding occurs, e.g., pregnancy tests, urine-albumin tests and C-reactive protein (CRP) detection.
When choosing a nitrocellulose membrane for lateral flow point-of-care tests (POCT), quality assurance and membrane consistency are critical to give you confidence in your test performance from development through manufacturing to implementation.
Nitrocellulose membranes are the heart of lateral flow assays and need to demonstrate:
- Highly consistent wicking rate and thickness—variations in either can have detrimental effects on assay sensitivity, reproducibility, and reagent consumption.
- Consistent reproducibility—protein binding levels which are highly consistent to facilitate reliable assay performance.
- Clear results—low background levels which enable crisp capture lines and easy-to-read results.
- Clear surface appearance—controlled surface quality of the membrane to ensure freedom from visual defects, discolouration and dust.
- Result timing—quality assured wicking speed for predictable result time.
Eliminate concerns over variability of your media so that you can concentrate on optimisation of other test and manufacturing variables.
Membrane consistency for assay reproducibility and sensitivity: Vivid™ Lateral Flow Nitrocellulose
With quality assured manufacturing and defined intra- and inter-lot-to-lot consistency, our Vivid Lateral Flow Nitrocellulose (LFNC) offers a reliable media for the development of lateral flow diagnostic point-of-care tests. Pall’s Vivid LFNC membranes fulfil all the criteria to enable the development and manufacture of a diverse range of tests with reliability and reproducibility:
- Strong consistency and high duplication rate: intra- and inter-lot performance for wicking time and thickness is tightly controlled resulting in low defined coefficients of variation (CV) between 5 and 10%.
- Quality: designed and tested specifically for diagnostic applications to ensure the materials meet stringent requirements for diagnostic assay development and manufacturing.
- Reliability: large-scale manufacturing capacity with lot-to-lot traceability.
- Clarity: straight and uniform migration front and controlled surface quality with low background for sharp capture lines and easy-to-read results.
- Choice: range of defined capillary speeds allowing you to select the sensitivity of the diagnostic test.
- Sensitivity: high sensitivity with dilute concentrations of target analytes.
- Dependable performance: constructed using pure nitrocellulose that does not contain interfering substances or post-treatments that may affect assay performance.
Consistency of membrane thickness
The thickness of the reaction membrane has a direct impact on its signal generation. Consequently, any variations both intra- or inter-lot will have an impact on point-of-care test device manufacturing and the final assay performance. In the data drawn from three lots, measuring the thickness of the membrane every 2.5 cm down a sample piece of material, the coefficient of variation was measured as ≤2.6% for Vivid 90 LFNC membrane with average thickness for all sample points being 217.1 ± 2.9 μm (Graph 1), and the coefficient of variation for Vivid 120 LFNC membrane was ≤4.6% with average thickness for all sample points being 196.7 ± 8.1 μm (Graph 2).
Uniformity of capillary speed/wicking
Assay sensitivity is maintained with consistency of the wicking rate of the nitrocellulose membrane. By maintaining a uniform sample front that travels along the membrane at a consistent speed, the target analyte is maintained in a homogenous concentration. This ensures that the target analyte present in the sample has adequate time to bind to the capture antibody resulting in reproducible results from lot to lot. The wicking rate of the Vivid 90 and Vivid 120 LFNC membranes both exhibit CVs for intra- and inter-lot consistency of ≤ 10% (Tables 2 and 3).
Medical diagnostics business partnership
Medical diagnostic teams need a reliable business partner with expertise in technology innovations and state of the art engineering. Pall executes manufacturing processes to ensure regulatory compliance and meet quality standards. Our diagnostic products are manufactured in accordance with ISO 9001.
Pall understands that the world of medical diagnostics gets more complicated every day. We know you’re counting on our team to provide you with quality products, so you can provide your patients with insight and resolution.