Miniaturization of organically doped sol-gel materials: a microns-size fluorescent pH sensor

Abstract Miniaturization of a reactive doped sol-gel material is described. A reversible fluorescent pH sensor was constructed by placing a pyranine doped SiO 2 sol-gel matrix at a 10 μm tip of a metal coated micropipette. Subsecond response time was achieved by further downscaling to ≈ 1 μm. Using optical near-field microscopy configuration, these observations demonstrate the potential of constructing a variety of miniaturized sensors and chemical manipulators, by doping the sol-gel matrix with a suitable reagent.

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