Fig. 4From: Gold-based nanoplatform for a rapid lateral flow immunochromatographic test assay for gluten detectionOptimization of antibody concentration for conjugation. (a) Color changes of the AuNPs with different antibody concentrations (0.4, 0.6, 0.8, 1, 2, 4, 6, 8 μg/mL) in the presence of NaClchanges were observed by the naked eye to determination optimal pH). (b) UV–Vis spectra of AuNPs with various antibody concentrations in presence of NaClBack to article page