Why Does My Gold Turn Purple/Blue?
If your red colloidal gold turns purple or blue, it has aggregated (clumped). This kills assay performance. Causes include incorrect pH during conjugation or insufficient blocking.
Stabilization
Ensure your gold nanoparticles are capped with a high-quality stabilizer like BSA or PEG. Due Bio provides pre-conjugated Gold-Antibody solutions and high-stability bare gold specifically for LFA.