Figure 1.

The microsphere insulin detection system. (A) Streptavidin-coated microspheres, at approximately 10 µm in diameter, were conjugated with biotin labeled capture anti-insulin antibodies. Then microsphere sensors were exposed to a solution containing insulin, and thereafter a fluorescent secondary antibody was added, followed by a wash step. (B) A typical image of microspheres, mostly found in singlets, is shown on the left as seen either under phase contrast, or on the right as imaged with fluorescence microscopy (excitation 494 nm, emission 519 nm).