Photonic band gap multilayers (PBGM) containing quarter wave stacks of alternating SiO2/TiO2 layers generate surface electromagnetic waves (SEWs) at a specific laser wavelength.  PBGMs were used to observe label-free protein/antibody binding events at the multilayer surface with higher optical sensitivity than for fluorescent-labeled proteins and antibodies on glass. Here we report the investigation of nonlinear enhancement of fluorescence through coupling with SEWs. MATLAB simulations show that SEWs are maximized inside the PBGM top layer, which was replaced with a mesoporous SiO2 (m-SiO2) film using established templated sol-gel synthesis procedures.  After calcining, organized mesopores were formed with 400 nm-700 nm profilometric thicknesses. Electron microscopy confirmed a hexagonal mesopore structure. Films were treated with 3-aminopropyl triethoxysilane to functionalize the surface with Cy5, a cyanine dye commonly used as a fluorescent tag. Fluorescence spectroscopy of dye-functionalized m-SiO2 films on fused silica and on PBGM was quantified to determine sensitivity limits.

Dye-tagged mesoporous silicate thin films to test nonlinear fluorescence enhancement

246th National Meeting (2013)

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