Hello,
I am performing research with the lateral-flow immunoassay (LFA) and am experiencing a large quantity of particles getting stuck at the interface between the fiberglass paper sample pad and the nitrocellulose membrane. I am working with gold coated magnetic nanoparticles (Au@Fe3O4) that are within the size range of 100-200 d.nm verified via DLS and was wondering if anyone had any tips to reduce particle accumulation at this interface, whether through membrane/sample pad blocking or different running buffer usage. I have previously worked with gold nanoparticles, and never experienced a similar issue.
The picture shows an untreated LFA with the aforementioned particles, wrapped in Parafilm to apply pressure. The same result occurs when it is not wrapped.
Thanks in advance.
Hi,
This is unfortunately a fairly common problem in LFAs. It occurs from reporter particle aggregates that are small enough to pass through the conjugate pad but large enough to get stuck in the nitrocellulose.
Sometimes, the problem is caused by the sample material or suboptimal pH and salinity in the buffer. Running the assay without any detergent (e.g. tween-20) will also result in this. These scenarios are easy to fix.
However, some antibodies cause trouble by aggregating the reporter particles by themselves. In case of such problematic, sticky antibody, lowering the amount of the antibody used in the reporter conjugation might help.
-etvi
Etvi Juntunen Thank you for your tips and recommendations! I appreciate it greatly!
Hello dear humza
You can use 1% casein sodium salt in your sample diluent (running buffer) that improve your run