Development and cellular applications of fiber optic nitric oxide sensors based on a gold-adsorbed fluorophore

A new design for optochemical sensors has been applied to the development o f a nitric oxide selective fiber optic sensor. This sensor is composed of a fluorescein derivative dye attached to colloidal gold. The fluorescein dye rearranges as nitric oxide adsorbs onto the gold, inducing a decrease in t he fluorescence intensity of the dye. This mechanism has allowed preparatio n of fiber optic dye-based nitric oxide sensors, which have been made ratio -metric by addition of reference dye microspheres. Previously developed fas t, selective optical sensors for detection of aqueous nitric oxide involved a protein, such as cytochrome c'. The new fluorescein derivative chemical sensors have characteristics similar to those of the protein-based biosenso rs, including fast response times, excellent selectivity, and complete reve rsibility. In addition, the chemical sensors have advantages such as greate r stability and commercially available components, These sensors were utili zed to measure nitric oxide production by BALB/c mouse macrophages.