The membrane is considered the most critical element in LFA strips and nitrocellulose is by far the most commonly used material. Moreover, there are also ‘pillar-based’ capillary LFA devices used for deoxyribonucleic acid(DNA) hybridization detection (where micropillar arrays replace the membrane), which have the advantage of more precise control of the capillary flow. Important parameters characterizing a good membrane material are the capillary forces, as well as the ease of binding and immobilizing proteins necessary for subsequent selection, reaction and detection. A range of nitrocellulose pore sizes are available, from 0.05 to 12 μm. However, as the pores are not equally distributed (because of the manufacturing process), capillary flow time is a more accurate parameter and it should be used when selecting the most effective strip material. The capillary flow time is the time required for the liquid to travel to and completely fill the strip of the membrane.

-NC membrane is a polymer.

-The function of NC membrane is to fix specific target molecules through their adsorption characteristics in the test and control line, while the simple and test conjugate are guided to the reaction area. To achieve this goal, the membrane must have a uniform high protein adsorption capacity and a certain amount of porosity and wettability to ensure capillary flow of aqueous samples. The properties of many polymer porous membranes can meet some or all of the requirements.

-The nitrocellulose membrane is a critical component that contains the test and control line reagents and provies the readout of the results to the end user. During development, it is important to select the correct membrane type and optimize the striping parameters of your test and control line reagents to achieve the desired results.