Monolithic capillary electrophoresis device with integrated fluorescence detector

A monolithic capillary electrophoresis system with integrated on-chip fluor escence detector has been microfabricated on a silicon substrate. Photodiod es in the silicon substrate measure fluorescence emitted from eluting molec ules. The device incorporates an on-chip thin-film interference filter that prevents excitation light from inhibiting the fluorescence detection. A tr ansparent AZO conducting ground plane is also used to prevent the high elec tric fields used for the separation from interfering with the photodiode re sponse. Separations of DNA restriction fragments have been performed in the se devices with femtogram detection limits using SYBR Green I intercalating dye.