Just Google "lateral flow" and you will get a lot of information.

In any case, your question is a bit strange: do you have all the reagents for constructing a lateral flow device?

Sir i have google and try for my work also but i am getting success so that i am asking about that

Dear,

1) You had coated Antibody on NCM? at which concentration?

2) Coated Antibody on Gold colloidal Particle at which concentration?

3) Which stabilizer you had used for colloidal gold conjugate?

Please share your protocol, so i can help you.

sir, Iam using 5%sodium borate,1%sucrose and 1%BSA, 0.5% tween 20 and 0.05% sodium azide

Do you get a line appearing if you use your conjugates in solution form instead of dehydrating them on the conjugate pad? You should first try to verify binding in this way. If your conjugates do not bind, try to conjugate the antibodies onto the gold nanoparticles at different pH values for antibody gold nanoparticle incubation step (this assumes that you are not using covalent chemistry). After this, if you still have trouble getting a sandwich complex to form at the test line try to immobilize your target antigen at ~1 mg/mL on the nitrocellulose membrane to make a competitive-like LFA membrane and then test if any of your nanoprobes can bind to that spot. It is possible that you are just testing the wrong range of antigen for the sandwich assay so this competitive-like test will eliminate that variable. If you have properly screened the whole range of pH values during the antibody incubation stage and your antibody is the right choice for your antigen you should be able to get binding at this spot (this also assumes that you are using a running buffer and your conjugates are flowing through your membrane, you can start with just 1% BSA in solution and that usually will work adequately for this type of screening test). Then you can try to dehydrate these conjugates on the conjugate pad. I would also start with just 1% BSA in sodium borate in the conjugate pad. Occasionally I have had issues with dehydrating Tween 20 in the conjugate pad. My recommendation is to always start simple and then slowly add new components into your assay if needed.