Recording neural signals from delicate autonomic nerves is a challenging task that requires the development of a lowinvasive neural interface with highly selective,micrometer-sized electrodes.This paper reports on the...Recording neural signals from delicate autonomic nerves is a challenging task that requires the development of a lowinvasive neural interface with highly selective,micrometer-sized electrodes.This paper reports on the development of a three-dimensional(3D)protruding thin-film microelectrode array(MEA),which is intended to be used for recording low-amplitude neural signals from pelvic nervous structures by penetrating the nerves transversely to reduce the distance to the axons.Cylindrical gold pillars(O 20 or 50μm,~60μm height)were fabricated on a micromachined polyimide substrate in an electroplating process.Their sidewalls were insulated with parylene C,and their tips were optionally modified by wet etching and/or the application of a titanium nitride(TiN)coating.The microelectrodes modified by these combined techniques exhibited low impedances(~7 kΩ at 1 kHz for ∅ 50μm microelectrode with the exposed surface area of~5000μm^(2))and low intrinsic noise levels.Their functionalities were evaluated in an ex vivo pilot study with mouse retinae,in which spontaneous neuronal spikes were recorded with amplitudes of up to 66μV.This novel process strategy for fabricating flexible,3D neural interfaces with low-impedance microelectrodes has the potential to selectively record neural signals from not only delicate structures such as retinal cells but also autonomic nerves with improved signal quality to study neural circuits and develop stimulation strategies in bioelectronic medicine,e.g.,for the control of vital digestive functions.展开更多
Direct stimulation of peripheral nerves with implantable electrodes successfully provided sensory feedback to amputees while using hand prostheses.Longevity of the electrodes is key to success,which we have improved f...Direct stimulation of peripheral nerves with implantable electrodes successfully provided sensory feedback to amputees while using hand prostheses.Longevity of the electrodes is key to success,which we have improved for the polyimide-based transverse intrafascicular multichannel electrode(TIME).The TIMEs were implanted in the median and ulnar nerves of three trans-radial amputees for up to six months.We present a comprehensive assessment of the electrical properties of the thin-film metallization as well as material status post explantationem.The TIMEs stayed within the electrochemical safe limits while enabling consistent and precise amplitude modulation.This lead to a reliable performance in terms of eliciting sensation.No signs of corrosion or morphological change to the thin-film metallization of the probes was observed by means of electrochemical and optical analysis.The presented longevity demonstrates that thin-film electrodes are applicable in permanent implant systems.展开更多
基金financed by the German Federal Ministry of Education and Research(BMBF)within the funding program"Individualisierte Medizintechnik"under grant 13GW0271C(NEPTUN)received financial support from the State Ministry of Baden-Wuerttemberg for Economic Affairs,Labor and Tourism+1 种基金Thomas Stieglitz was partly supported by the BrainLinks-BrainTools Cluster of Excellence funded by the German Research Foundation-DFG(EXC 1086)funded by the Federal Ministry of Economics,Science and Arts of Baden-Württemberg within the sustainability program for projects of excellence initiative II.
文摘Recording neural signals from delicate autonomic nerves is a challenging task that requires the development of a lowinvasive neural interface with highly selective,micrometer-sized electrodes.This paper reports on the development of a three-dimensional(3D)protruding thin-film microelectrode array(MEA),which is intended to be used for recording low-amplitude neural signals from pelvic nervous structures by penetrating the nerves transversely to reduce the distance to the axons.Cylindrical gold pillars(O 20 or 50μm,~60μm height)were fabricated on a micromachined polyimide substrate in an electroplating process.Their sidewalls were insulated with parylene C,and their tips were optionally modified by wet etching and/or the application of a titanium nitride(TiN)coating.The microelectrodes modified by these combined techniques exhibited low impedances(~7 kΩ at 1 kHz for ∅ 50μm microelectrode with the exposed surface area of~5000μm^(2))and low intrinsic noise levels.Their functionalities were evaluated in an ex vivo pilot study with mouse retinae,in which spontaneous neuronal spikes were recorded with amplitudes of up to 66μV.This novel process strategy for fabricating flexible,3D neural interfaces with low-impedance microelectrodes has the potential to selectively record neural signals from not only delicate structures such as retinal cells but also autonomic nerves with improved signal quality to study neural circuits and develop stimulation strategies in bioelectronic medicine,e.g.,for the control of vital digestive functions.
文摘Direct stimulation of peripheral nerves with implantable electrodes successfully provided sensory feedback to amputees while using hand prostheses.Longevity of the electrodes is key to success,which we have improved for the polyimide-based transverse intrafascicular multichannel electrode(TIME).The TIMEs were implanted in the median and ulnar nerves of three trans-radial amputees for up to six months.We present a comprehensive assessment of the electrical properties of the thin-film metallization as well as material status post explantationem.The TIMEs stayed within the electrochemical safe limits while enabling consistent and precise amplitude modulation.This lead to a reliable performance in terms of eliciting sensation.No signs of corrosion or morphological change to the thin-film metallization of the probes was observed by means of electrochemical and optical analysis.The presented longevity demonstrates that thin-film electrodes are applicable in permanent implant systems.
