Gold/silica thin film for biosensors applications: Metal enhanced fluorescence

The work described here concerns the fabrication of cost-effective biosensors that permit to amplify a fluorescence signal without a complex nano-structuration of the surface. The idea is to put to profit the natural pseudo nano-structuring that is observed when depositing metallic layers by various micro-fabrication techniques. This new architecture consists of a glass substrate. A gold film is deposited on the top of it and a silica layer onto the gold. A dye (Cy5) is then absorbed onto the surface and the fluorescence intensity is measured. This intensity depends on the distance between the dye and the metal. It also depends on the properties of the metallic film. The goal of the work is to determine which gold deposition method leads to the highest fluorescence amplification and which silica thickness is required to achieve this amplification.