A 1μm diameter tip fiber-based surface plasmon resonance system for single unit optical neural recording.
ABSTRACT A gold-deposited optical fiber sensor system based on surface plasmon resonance (SPR) was developed for optical measurement of neuronal activity. To enhance the sensitivity of localized SPR and to make a precise and safe contact with the cellular membrane, we designed a tapered optical probe of 1 μm diameter at the tip of the fiber. By wet etching and gold evaporating processes, pencil-shaped optical probes were successfully fabricated. The SPR system with the sharp optical probe was integrated with a conventional patch clamping system to realize a simultaneous optical and electrical recording on a single neuron. Although the shape of optical signal is not clear due to tiny change of intrinsic optical properties on the neuron, optical and electrical signals were simultaneously changed by capsaicin stimulation. Furthermore, our designed fiber probe can be applicable to localized optical stimulation as well as in vivo optical neuroprosthetic devices.
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ABSTRACT: We propose a novel method by chemical etching using hydrofluoric (HF) acid and a buffered HF solution (BHF) to fabricate a pencil-shaped fiber probe for near-field optics. We succeeded in producing such probes with high reproducibility using a dispersion-compensating fiber having the high GeO<sub>2</sub> doped core. The method involves tapering of the cladding, then sharpening of the core. The fabricated probe has a conical tip with a cone angle of 20° and an apex diameter of less than 10 nmJournal of Lightwave Technology 11/1996; · 2.86 Impact Factor