A5070484840- Neuroscience and Neural Engineering
- Photoreceptor and optogenetics research
- Advanced Memory and Neural Computing
- Neural dynamics and brain function
- Molecular Communication and Nanonetworks
- EEG and Brain-Computer Interfaces
- Advanced MEMS and NEMS Technologies
- Light effects on plants
- Metallurgical and Alloy Processes
- Nanomaterials and Printing Technologies
- Semiconductor materials and devices
- Muscle activation and electromyography studies
- Gas Sensing Nanomaterials and Sensors
- Adhesion, Friction, and Surface Interactions
- Tribology and Lubrication Engineering
- Metal and Thin Film Mechanics
- Laser Material Processing Techniques
- Thin-Film Transistor Technologies
- Acoustic Wave Resonator Technologies
- Analog and Mixed-Signal Circuit Design
- Photosynthetic Processes and Mechanisms
- ZnO doping and properties
University of Freiburg
2016-2024
Brain (Germany)
2024
Bernstein Center for Computational Neuroscience Freiburg
2024
TU Wien
2005
This study reports the realization of an optical cochlear implant (oCI) with optimized thermomechanical properties for optogenetic experiments. The oCI probe comprises 144 miniaturized light-emitting diodes (μLEDs) distributed along a bendable, 1.5-cm-long, 350-μm-wide and 26-μm-thick shaft, individually controlled via n × p matrix interconnection. In contrast to our earlier approach based on polyimide (PI) epoxy resin different thermal expansion coefficients, μLEDs interconnecting wires are...
Article29 June 2020Open Access Transparent process μLED-based optical cochlear implants for spectrally selective activation of the auditory nerve Alexander Dieter orcid.org/0000-0002-9154-4833 Institute Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Germany Göttingen Graduate School Neurosciences Molecular Biosciences, Search more papers by this author Eric Klein orcid.org/0000-0003-2593-059X Department Microsystems Engineering (IMTEK), Freiburg, Daniel Keppeler...
We report on the design, fabrication, assembly and characterization of an innovative neural probe with optical functionality for optogenetic applications in neuroscientific research. In contrast to existing systems, thin-film micro light-emitting diodes (μLEDs) are directly integrated probes based silicon (Si) substrates using a wafer-level bonding process. It allows considerably shrink overall dimensions despite increased density light sources. Our new system approach demonstrates...
This paper reports on the development, characterization and in vivo validation of compact optical neural probes. These novel intracerebral devices comprise micro light-emitting diodes ( μLEDs) integrated along their slender probe shanks with up to 20 μLEDs per device. Blue light a peak wavelength 455 nm is emitted from circular apertures 100 μm diameter. The are structured GaN-on-sapphire wafers subsequently transferred onto silicon (Si) carrier wafers. wafer-scale transfer process provides...
Compared to conventional rigid silicon probes, flexible penetrating neural implants exhibit improved mechanical compliance with brain tissue, enabling high-quality recordings over extended periods of time. However, the length implantable shank and extension cable most devices falls short clinical electrodes used in diagnostics treatment neurological disorders. In this study, we demonstrate design, fabrication, vivo validation polyimide-based probes a thin spiral-shaped that reaches 27...
This paper reports on the fabrication and characterization of spherical micro-lenses ( μ-lenses) made from polydimethylsiloxane (PDMS) their integration into optogenetic implants based micro light-emitting diodes μLEDs). The μ-lenses are fabricated using a reusable silicon mold realized by wet chemical HNA (hydrofluoric, nitric acetic acid) etching. It applies masking layer with openings as small 5 μm was optimized for hemispherical μ-lens cavities low surface roughness ). diameters down to...
Abstract Optogenetic control of cells is a key life sciences method and promises novel therapies. Here we report on ChReef, an improved variant the channelrhodopsin ChRmine. ChReef offers minimal photocurrent desensitization, unitary conductance 80 fS closing kinetics 30 ms, which together enable reliable optogenetic at low light levels (nano-Joule) with good temporal fidelity allows sustained stimulation. We demonstrate efficient red-light pacing depolarization block ChReef-expressing...
This paper reports on the yield optimization of a wafer-level indium (In)-based bonding process for joining 4-inch sapphire and silicon (Si) wafers. The allows to realize neural probes with integrated micro light-emitting diodes (μLED) optogenetic applications. substrates comprise 6-μm-thick gallium nitride (GaN)-based μLEDs lateral dimensions down 50×50 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , which are transferred by...
This paper reports on the optimization of wafer-scale bonding micro-light-emitting diodes (µLEDs) four-inch sapphire wafers onto silicon (Si) substrates using an indium–gold (In–Au) reflow process. The yield was optimized from initial values below 10% to 100% by applying a systematic variation two most relevant parameters, namely indium (In) pad height t2 and relative area Q. fabrication process is designed reliably transfer mLEDs Si substrates. demonstrated realizing optoelectronic probes...
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Abstract Optogenetics enables insights into the development of neural diseases. Custom-designed probes are necessary to access targeted brain regions. Multifunctional and mechanically flexible with minimal footprint, comprising fluidic channels for drug delivery, light sources optical stimulation, micro electrodes electro-physiological readout beneficial due reduced tissue trauma consequently increased long-term stability. This study introduces a compliant probe that provides microfluidic...
This paper reports on new schemes based the concept of tri-state switching for routing linear arrays light-emitting diodes (LEDs) slim substrates. The use a minimal number wires in single-metal planar technologies, where are not allowed to cross. They have common that LEDs, NL, addressable by NW is given NL = 4NW − 6. designs built family hierarchically interconnected structures with (2n+1 2) LEDs and (2n−1 + 1) wires, positive integers n. A process termed expansion straightforwardly extends...
This paper reports on the fabrication, assembly, characterization and validation of a novel opto-electrical cardiac stimulator designed to augment mechanical pacing device. The integration miniaturized electrodes blue light-emitting diode (LED) chips pacer tip with diameter 1 mm enables application multimodal stimuli in one location surface isolated murine hearts. is based two separate polyimide (PI) substrates each thickness 10 μm combined into functional unit dedicated assembly...
This study reports on a fully autonomous system comprising wireless headstage and an array of micro light-emitting diodes (µLED) integrated in flexible neural probe for optogenetic experiments. The 49 µLEDs (50×50 µm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) are arranged at minimal pitch only 100 µm. µLED-based probes realized using novel, single-sided fabrication process the expitaxial sapphire substrate that avoids delicate...