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 of 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 the fluorescence intensity of the dye. This mechanism has allowed preparation of fiber optic dye-based nitric oxide sensors, which have been made ratio-metric by addition of reference dye microspheres. Previously developed fast, 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 biosensors, including fast response times, excellent selectivity, and complete reversibility. In addition, the chemical sensors have advantages such as greater stability and commercially available components. These sensors were utilized to measure nitric oxide production by BALB/c mouse macrophages.