Electronics with shape actuation for minimally invasive spinal cord stimulation.

Spinal cord stimulation is one of the oldest and most established neuromodulation therapies. However, today, clinicians need to choose between bulky paddle-type devices, requiring invasive surgery under general anesthetic, and percutaneous lead-type devices, which can be implanted via simple needle puncture under local anesthetic but offer clinical drawbacks when compared with paddle devices. By applying photo- and soft lithography fabrication, we have developed a device that features thin, flexible electronics and integrated fluidic channels. This device can be rolled up into the shape of a standard percutaneous needle then implanted on the site of interest before being expanded in situ, unfurling into its paddle-type conformation. The device and implantation procedure have been validated in vitro and on human cadaver models. This device paves the way for shape-changing bioelectronic devices that offer a large footprint for sensing or stimulation but are implanted in patients percutaneously in a minimally invasive fashion

Minimization of baseband electrical memory effects in GaN HEMTs using active IF load-pull

This paper presents a rigorous way to quantify the role played by higher baseband impedances in determining baseband electrical memory effects observed in power transistors under two-carrier excitation. These effects typically appear not only as asymmetrical distortion terms in the frequency domain, but also more reliably as a recognizeable hysteresis or looping in the dynamic transfer characteristics extracted from measured input voltage and output current envelopes of a power device. Investigations have been carried out using a commercially available 10W GaN HEMT device characterised at 2GHz within a high-power modulated wavefor measurement system. Active IF loadpull has been employed to present specific baseband impedance environments, allowing the sensitivity of IMD symmetry to baseband impedance variations to be investigated

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Ennek a Tanári kézikönyvnek alapvető újdonsága, hogy a korszerű ismeretek mellett a történelmi gondolkodás elsajátításához is segítséget nyújt.A történelem tanárok, és a témakört kedvelők új „forrásirányú’ szemszögből ismerhetik meg az Őskor, Ókor, és a Középkor történetét

X-Ray Markers for Thin Film Implants.

Funder: University of Cambridge; Id: http://dx.doi.org/10.13039/501100000735Funder: Health Education EnglandImplantable electronic medical devices are used in functional mapping of the brain before surgery and to deliver neuromodulation for the treatment of neurological and neuropsychiatric disorders. Their electrode arrays are assembled by hand, and this leads to bulky form factors with limited flexibility and low electrode counts. Thin film implants, made using microfabrication techniques, are emerging as an attractive alternative, as they offer dramatically improved conformability and enable high density recording and stimulation. A major limitation of these devices, however, is that they are invisible to fluoroscopy, the most common method used to monitor the insertion of implantable electrodes. Here, the development of mechanically flexible X-ray markers using bismuth- and barium-infused elastomers is reported. Their X-ray attenuation properties in human cadavers are explored and it is shown that they are biocompatible in cell cultures. It is further shown that they do not distort magnetic resonance imaging images and their integration with thin film implants is demonstrated. This work removes a key barrier for the adoption of thin film implants in brain mapping and in neuromodulation.We gratefully acknowledge the quality of the facility and the assistance provided by all the staff at the Evelyn Cambridge Surgical Training Centre whose HTA license made it possible and where part of this work was undertaken. We also acknowledge the Diagnostic Imaging Department at the Queen’s Veterinary School Hospital for their assistance in capturing x-ray images. Funding: BJW acknowledges funding from the Engineering and Physical Sciences Research Council Centre for Doctoral Training in Sensor Technologies and Applications (EP/L015889/1). LC acknowledges funding from the UK Engineering and Physical Sciences Research Council Centre for Doctoral Training in Sensor Technologies for a Healthy and Sustainable Future (EP/S023046/1). SJKO and OAS acknowledge funding from ERC consolidator grant (CAM RIG, 726470). AER acknowledges funding from the UK Engineering and Physical Sciences Research Council (EPSRC) (EP/S009000/1). CMP acknowledges funding from the University of Cambridge Borysiewicz Fellowship program and the Biotechnology and Biological Sciences Research Council David Phillips Fellowship. DGB. is supported by Health Education England and the National Institute for Health Research HEE/NIHR ICA Program Clinical Lectureship (CL-2019-14-004) and acknowledge funding for Royal College of Surgeons of England (G110237) and Academy of Medical Sciences (G111425). Additional project support and funding were provided by the EPSRC IAA Follow-on Fund Project for Spinal Cord Stimulator (RG90413) and Medical Research Council Confidence in Concept (RG84584). The devices were built in the laboratory for prototyping soft neuroprosthetic technologies, funded by the Sir Jules Thorn charitable trust (233838)

Tunable Organic Active Neural Probe Enabling Near-Sensor Signal Processing.

Neural recording systems have significantly progressed to provide an advanced understanding and treatment for neurological diseases. Flexible transistor-based active neural probes exhibit great potential in electrophysiology applications due to their intrinsic amplification capability and tissue-compliant nature. However, most current active neural probes exhibit bulky back-end connectivity since the output is current, and the development of an integrated circuit for voltage output is crucial for near-sensor signal processing at the abiotic/biotic interface. Here, inkjet-printed organic voltage amplifiers are presented by monolithically integrating organic electrochemical transistors and thin-film polymer resistors on a single, highly flexible substrate for in vivo brain activity recording. Additive inkjet printing enables the seamless integration of multiple active and passive components on the somatosensory cortex, leading to significant noise reduction over the externally connected typical configuration. It also facilitates fine-tuning of the voltage amplification and frequency properties. The organic voltage amplifiers are validated as electrocorticography devices in a rat in vivo model, showing their ability to record local field potentials in an experimental model of spontaneous and epileptiform activity. These results bring organic active neural probes to the forefront in applications where efficient sensory data processing is performed at sensor endpoints

X-Ray Markers for Thin Film Implants.

Implantable electronic medical devices are used in functional mapping of the brain before surgery and to deliver neuromodulation for the treatment of neurological and neuropsychiatric disorders. Their electrode arrays are assembled by hand, and this leads to bulky form factors with limited flexibility and low electrode counts. Thin film implants, made using microfabrication techniques, are emerging as an attractive alternative, as they offer dramatically improved conformability and enable high density recording and stimulation. A major limitation of these devices, however, is that they are invisible to fluoroscopy, the most common method used to monitor the insertion of implantable electrodes. Here, we report the development of mechanically flexible x-ray markers using bismuth- and barium-infused elastomers. We explore their x-ray attenuation properties in human cadavers and show that they are biocompatible in cell cultures. We further show that they do not distort MRI images and demonstrate their integration with thin film implants. This work removes a key barrier for the adoption of thin film implants in brain mapping and in neuromodulation. This article is protected by copyright. All rights reserved.We gratefully acknowledge the quality of the facility and the assistance provided by all the staff at the Evelyn Cambridge Surgical Training Centre whose HTA license made it possible and where part of this work was undertaken. We also acknowledge the Diagnostic Imaging Department at the Queen’s Veterinary School Hospital for their assistance in capturing x-ray images. Funding: BJW acknowledges funding from the Engineering and Physical Sciences Research Council Centre for Doctoral Training in Sensor Technologies and Applications (EP/L015889/1). LC acknowledges funding from the UK Engineering and Physical Sciences Research Council Centre for Doctoral Training in Sensor Technologies for a Healthy and Sustainable Future (EP/S023046/1). SJKO and OAS acknowledge funding from ERC consolidator grant (CAM RIG, 726470). AER acknowledges funding from the UK Engineering and Physical Sciences Research Council (EPSRC) (EP/S009000/1). CMP acknowledges funding from the University of Cambridge Borysiewicz Fellowship program and the Biotechnology and Biological Sciences Research Council David Phillips Fellowship. DGB. is supported by Health Education England and the National Institute for Health Research HEE/NIHR ICA Program Clinical Lectureship (CL-2019-14-004) and acknowledge funding for Royal College of Surgeons of England (G110237) and Academy of Medical Sciences (G111425). Additional project support and funding were provided by the EPSRC IAA Follow-on Fund Project for Spinal Cord Stimulator (RG90413) and Medical Research Council Confidence in Concept (RG84584). The devices were built in the laboratory for prototyping soft neuroprosthetic technologies, funded by the Sir Jules Thorn charitable trust (233838)