Copper‐Mediated Amplification Allows Readout of Immunoassays by the Naked Eye

An eye for color: Antibodies modified by CuO nanoparticles (NPs) are subjected to immunoreaction with the release of CuII, which can be detected by click chemistry. The Cu acts as a catalyst that induces aggregation of Au NPs functionalized with azide and alkyne groups, which can be seen as a color change (see picture). The detection of HIV in blood serum of infected patients is demonstrated.