Figure 1.
Detection principles of AuNP immunosensors. The sensor surface after protein capture is shown on the left in the center. On the bottom left is a tapping-mode AFM image of a AuNP film that serves as the immunosensor platform. A) The immunosensor after treatment with biotinylated Ab2 followed by streptavidin-modified HRP resulting in HRP–Ab2 and providing 14–16 labels per binding event. B) The immunosensor after treatment with massively labeled Ab2–MB–HRP particles to obtain amplification by providing around 500000 enzyme labels per binding event.