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: Neuronal networks underlie memory storage and information processing in the human brain, and ultimately participate in what Eccles referred to as "the creation of consciousness". Moreover, as physiological dysfunctions of neurons almost always translate into serious health issues, the study of the dynamics of neuronal networks has become a major avenue of research, as well as their response to pharmacological tampering. Planar microelectrode arrays represent a unique tool to investigate such dynamics and interferences, as they allow one to observe the activity of neuronal networks spread in both space and time. We will here review the major results obtained with microelectrode arrays and give an overview of the latest technological developments in the field, including our own efforts to develop the potential of this already powerful technology.Journal of Bioscience and Bioengineering 09/2005; 100(2):131-43. DOI:10.1263/jbb.100.131 · 1.79 Impact Factor
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ABSTRACT: We demonstrate that surface plasmon resonance (SPR) is applicable to the optical detection of neural signals. A low-noise SPR sensor was developed as a label- and artifact-free method for the extracellular recording of neural activity. The optical responses obtained from a rat sciatic nerve were highly correlated with simultaneously recorded electrical responses. Additional studies with stimulation intensity and lidocaine further confirmed that the optically measured signals originated from neural activities.Optics Letters 06/2008; 33(9):914-6. DOI:10.1364/OL.33.000914 · 3.18 Impact Factor
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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; DOI:10.1109/50.541212 · 2.86 Impact Factor