Depiction of the magnetic enrichment lateral flow immunoassay. A biotinylated antibody is added to a plasma sample containing the target biomarker(s). An equal volume of buffer containing streptavidin-pNIPAm-gold nanoparticles, pNIPAm magnetic nanoparticles, and free pNIPAm polymer is added. Upon heating, the mixed AuNP/mNP aggregates are separated by a magnet. After discarding the supernatant, the captured aggregates are redissolved into a smaller volume of cool buffer, resulting in particle disaggregation and 50-fold enrichment. The enriched mixture is then applied directly to an immunochromatographic assay membrane with functionalized test and control line antibody regions.