Journal articles: 'Implantable microelectrode arrays'

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Wei, Wen Jing, Yi Lin Song, Wen Tao Shi, Chun Xiu Liu, Ting Jun Jiang, and Xin Xia Cai. "A Novel Microelectrode Array Probe Integrated with Electrophysiology Reference Electrode for Neural Recording." Key Engineering Materials 562-565 (July 2013): 67–73. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.67.

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Nowadays, the study of brain function is advanced by implantable microelectrode arrays for they can simultaneously record signals from different groups of neurons regarding complex neural processes. This article presents the fabrication, characterization and use in vivo neural recording of an implantable microelectrode array probe which integrated with electrophysiology reference electrode. The probe was implemented on Silicon-On-Insulator (SOI) wafer using Micro-Electro-Mechanical-Systems (MEMS) methods, so the recording-site configurations and high-density electrode placement could be precisely defined. The 16 recording sites and the reference electrode were made of platinum. Double layers of platinum electrodes were used so that the width of the reference electrode was as small as 6 μm. The average impedance of the microelectrodes was 0.13 MΩ at 1 kHz. The probe has been employed to record the neural signals of rat, and the results showed that the signal-to-noise ratio (SNR) of the novel probe was as high as 10 and the ordinary probe was 3. Among the 16 recording sites, there are 9 effective sites having recorded useful signals for the probe with reference electrode and 6 for the ordinary probe.

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Hetke, J. F., J. L. Lund, K. Najafi, K. D. Wise, and D. J. Anderson. "Silicon ribbon cables for chronically implantable microelectrode arrays." IEEE Transactions on Biomedical Engineering 41, no. 4 (April 1994): 314–21. http://dx.doi.org/10.1109/10.284959.

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Zarifi, Mohammad Hossein, Javad Frounchi, Mohammad Ali Tinati, and Jack W. Judy. "PLATINUM-BASED CONE MICROELECTRODES FOR IMPLANTABLE NEURAL RECORDING APPLICATIONS." Biomedical Engineering: Applications, Basis and Communications 22, no. 03 (June 2010): 249–54. http://dx.doi.org/10.4015/s1016237210001992.

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There have been significant advances in fabrication of high-density microelectrode arrays using silicon micromachining technology in neural signal recording systems. The interface between microelectrodes and chemical environment is of great interest to researchers, working on extracellular stimulation. This interface is quite complex and must be modeled carefully to match experimental results. Computer simulation is a method to increase the knowledge about these arrays and to this end the finite element method (FEM) provides a strong environment for investigation of relative changes of the electrical field extension surrounding an electrode positioned in chemical environment. In this paper FEM simulation environment is used for modeling the metal–chemical interface, which provides helpful information about noise, impedance, and bandwidth for circuit designers to design the front-end electronics of these systems, more efficiently and reliable.

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Johnson, Matthew D., Robert K. Franklin, Matthew D. Gibson, Richard B. Brown, and Daryl R. Kipke. "Implantable microelectrode arrays for simultaneous electrophysiological and neurochemical recordings." Journal of Neuroscience Methods 174, no. 1 (September 2008): 62–70. http://dx.doi.org/10.1016/j.jneumeth.2008.06.036.

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Green, Rylie A., Juan S. Ordonez, Martin Schuettler, Laura A. Poole-Warren, Nigel H. Lovell, and Gregg J. Suaning. "Cytotoxicity of implantable microelectrode arrays produced by laser micromachining." Biomaterials 31, no. 5 (February 2010): 886–93. http://dx.doi.org/10.1016/j.biomaterials.2009.09.099.

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Seymour, John P., Nick B. Langhals, David J. Anderson, and Daryl R. Kipke. "Novel multi-sided, microelectrode arrays for implantable neural applications." Biomedical Microdevices 13, no. 3 (February 8, 2011): 441–51. http://dx.doi.org/10.1007/s10544-011-9512-z.

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Ghane-Motlagh, Bahareh, and Mohamad Sawan. "High-Density Implantable Microelectrode Arrays for Brain-Machine Interface Applications." Advances in Science and Technology 96 (October 2014): 95–101. http://dx.doi.org/10.4028/www.scientific.net/ast.96.95.

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Microelectrode arrays (MEAs) act as an interface between electronic circuits and neural tissues of implantable devices. Biological response to chronic implantation of MEAs is an essential factor in determining a successful electrode design. Finding appropriate coating materials which are biocompatible and improve electrical properties of MEAs are among the main challenges. In this paper, we propose a novel, three-dimensional (3D), high-density, silicon-based MEAs for both neural recording and stimulation. Electrodes were fabricated using micromachining techniques. Geometrical features of these electrodes not only cause less tissue damage during insertion but also provide more contacts between the electrodes and targeted neural tissues. In order to achieve the proposed geometry, we introduce a novel masking method to coat variable-height electrodes with uniform and small tip-exposure. More importantly, compared to conventional techniques, the new masking method significantly improves process time and costs. This technique needs only one step masking and reduces the conventional masking steps from ten to three. In the next step, the active sites of the electrodes were coated with thin-films of molybdenum (Mo) and platinum (Pt) due to their ability to transfer between ionic and electronic current and to resist corrosion. Electrodes were characterized by scanning electron microscopy and impedance measurements. The average impedance of Mo and Pt electrodes at 1 kHz was 350 ± 50 kΩ and 150 ± 10 kΩ, respectively.

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Ji, J., and K. D. Wise. "An implantable CMOS circuit interface for multiplexed microelectrode recording arrays." IEEE Journal of Solid-State Circuits 27, no. 3 (March 1992): 433–43. http://dx.doi.org/10.1109/4.121568.

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de Haro, C., R. Mas, G. Abadal, J. Muñoz, F. Perez-Murano, and C. Domı́nguez. "Electrochemical platinum coatings for improving performance of implantable microelectrode arrays." Biomaterials 23, no. 23 (December 2002): 4515–21. http://dx.doi.org/10.1016/s0142-9612(02)00195-3.

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Black, Bryan J., Aswini Kanneganti, Alexandra Joshi-Imre, Rashed Rihani, Bitan Chakraborty, Justin Abbott, Joseph J. Pancrazio, and Stuart F. Cogan. "Chronic recording and electrochemical performance of Utah microelectrode arrays implanted in rat motor cortex." Journal of Neurophysiology 120, no. 4 (October 1, 2018): 2083–90. http://dx.doi.org/10.1152/jn.00181.2018.

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Multisite implantable electrode arrays serve as a tool to understand cortical network connectivity and plasticity. Furthermore, they enable electrical stimulation to drive plasticity, study motor/sensory mapping, or provide network input for controlling brain-computer interfaces. Neurobehavioral rodent models are prevalent in studies of motor cortex injury and recovery as well as restoration of auditory/visual cues due to their relatively low cost and ease of training. Therefore, it is important to understand the chronic performance of relevant electrode arrays in rodent models. In this report, we evaluate the chronic recording and electrochemical performance of 16-channel Utah electrode arrays, the current state-of-the-art in pre-/clinical cortical recording and stimulation, in rat motor cortex over a period of 6 mo. The single-unit active electrode yield decreased from 52.8 ± 10.0 ( week 1) to 13.4 ± 5.1% ( week 24). Similarly, the total number of single units recorded on all electrodes across all arrays decreased from 106 to 15 over the same time period. Parallel measurements of electrochemical impedance spectra and cathodic charge storage capacity exhibited significant changes in electrochemical characteristics consistent with development of electrolyte leakage pathways over time. Additionally, measurements of maximum cathodal potential excursion indicated that only a relatively small fraction of electrodes (10–35% at 1 and 24 wk postimplantation) were capable of delivering relevant currents (20 µA at 4 nC/ph) without exceeding negative or positive electrochemical potential limits. In total, our findings suggest mainly abiotic failure modes, including mechanical wire breakage as well as degradation of conducting and insulating substrates. NEW & NOTEWORTHY Multisite implantable electrode arrays serve as a tool to record cortical network activity and enable electrical stimulation to drive plasticity or provide network feedback. The use of rodent models in these fields is prevalent. We evaluated chronic recording and electrochemical performance of 16-channel Utah electrode arrays in rat motor cortex over a period of 6 mo. We primarily observed abiotic failure modes suggestive of mechanical wire breakage and/or degradation of insulation.

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Du, Jiangang, Ingmar H. Riedel-Kruse, Janna C. Nawroth, Michael L. Roukes, Gilles Laurent, and Sotiris C. Masmanidis. "High-Resolution Three-Dimensional Extracellular Recording of Neuronal Activity With Microfabricated Electrode Arrays." Journal of Neurophysiology 101, no. 3 (March 2009): 1671–78. http://dx.doi.org/10.1152/jn.90992.2008.

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Microelectrode array recordings of neuronal activity present significant opportunities for studying the brain with single-cell and spike-time precision. However, challenges in device manufacturing constrain dense multisite recordings to two spatial dimensions, whereas access to the three-dimensional (3D) structure of many brain regions appears to remain a challenge. To overcome this limitation, we present two novel recording modalities of silicon-based devices aimed at establishing 3D functionality. First, we fabricated a dual-side electrode array by patterning recording sites on both the front and back of an implantable microstructure. We found that the majority of single-unit spikes could not be simultaneously detected from both sides, suggesting that in addition to providing higher spatial resolution measurements than that of single-side devices, dual-side arrays also lead to increased recording yield. Second, we obtained recordings along three principal directions with a multilayer array and demonstrated 3D spike source localization within the enclosed measurement space. The large-scale integration of such dual-side and multilayer arrays is expected to provide massively parallel recording capabilities in the brain.

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Schuettler, M., S. Stiess, B. V. King, and G. J. Suaning. "Fabrication of implantable microelectrode arrays by laser cutting of silicone rubber and platinum foil." Journal of Neural Engineering 2, no. 1 (February 23, 2005): S121—S128. http://dx.doi.org/10.1088/1741-2560/2/1/013.

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Negi, S., R. Bhandari, L. Rieth, and F. Solzbacher. "In vitro comparison of sputtered iridium oxide and platinum-coated neural implantable microelectrode arrays." Biomedical Materials 5, no. 1 (February 2010): 015007. http://dx.doi.org/10.1088/1748-6041/5/1/015007.

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Zeng, Qi, Saisai Zhao, Hangao Yang, Yi Zhang, and Tianzhun Wu. "Micro/Nano Technologies for High-Density Retinal Implant." Micromachines 10, no. 6 (June 22, 2019): 419. http://dx.doi.org/10.3390/mi10060419.

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During the past decades, there have been leaps in the development of micro/nano retinal implant technologies, which is one of the emerging applications in neural interfaces to restore vision. However, higher feedthroughs within a limited space are needed for more complex electronic systems and precise neural modulations. Active implantable medical electronics are required to have good electrical and mechanical properties, such as being small, light, and biocompatible, and with low power consumption and minimal immunological reactions during long-term implantation. For this purpose, high-density implantable packaging and flexible microelectrode arrays (fMEAs) as well as high-performance coating materials for retinal stimulation are crucial to achieve high resolution. In this review, we mainly focus on the considerations of the high-feedthrough encapsulation of implantable biomedical components to prolong working life, and fMEAs for different implant sites to deliver electrical stimulation to targeted retinal neuron cells. In addition, the functional electrode materials to achieve superior stimulation efficiency are also reviewed. The existing challenge and future research directions of micro/nano technologies for retinal implant are briefly discussed at the end of the review.

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Jang, Jae-Won, Yoo Na Kang, Hee Won Seo, Boil Kim, Han Kyoung Choe, Sang Hyun Park, Maan-Gee Lee, and Sohee Kim. "Long-term in-vivo recording performance of flexible penetrating microelectrode arrays." Journal of Neural Engineering 18, no. 6 (November 19, 2021): 066018. http://dx.doi.org/10.1088/1741-2552/ac3656.

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Abstract Objective. Neural interfaces are an essential tool to enable the human body to directly communicate with machines such as computers or prosthetic robotic arms. Since invasive electrodes can be located closer to target neurons, they have advantages such as precision in stimulation and high signal-to-noise ratio (SNR) in recording, while they often exhibit unstable performance in long-term in-vivo implantation because of the tissue damage caused by the electrodes insertion. In the present study, we investigated the electrical functionality of flexible penetrating microelectrode arrays (FPMAs) up to 3 months in in-vivo conditions. Approach. The in-vivo experiment was performed by implanting FPMAs in five rats. The in-vivo impedance as well as the action potential (AP) amplitude and SNR were analyzed over weeks. Additionally, APs were tracked over time to investigate the possibility of single neuron recording. Main results. It was observed that the FPMAs exhibited dramatic increases in impedance for the first 4 weeks after implantation, accompanied by decreases in AP amplitude. However, the increase/decrease in AP amplitude was always accompanied by the increase/decrease in background noise, resulting in quite consistently maintained SNRs. After 4 weeks of implantation, we observed two distinctive issues regarding long-term implantation, each caused by chronic tissue responses or by the delamination of insulation layer. The results demonstrate that the FPMAs successfully recorded neuronal signals up to 12 weeks, with very stably maintained SNRs, reduced by only 16.1% on average compared to the first recordings, although biological tissue reactions or physical degradation of the FPMA were present. Significance. The fabricated FPMAs successfully recorded intracortical signals for 3 months. The SNR was maintained up to 3 months and the chronic function of FPMA was comparable with other silicon based implantable electrodes.

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Chakraborty, Bitan. "Electrochemical Properties of Sputtered Ruthenium Oxide Neural Stimulation and Recording Electrodes." Electrochem 4, no. 3 (July 24, 2023): 350–64. http://dx.doi.org/10.3390/electrochem4030023.

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A chronically stable electrode material with a low impedance for recording neural activity, and a high charge-injection capacity for functional electro-stimulation is desirable for the fabrication of implantable microelectrode arrays that aim to restore impaired or lost neurological functions in humans. For this purpose, we have investigated the electrochemical properties of sputtered ruthenium oxide (RuOx) electrode coatings deposited on planar microelectrode arrays, using an inorganic model of interstitial fluid (model-ISF) at 37 °C as the electrolyte. Through a combination of cyclic voltammetry (CV) and an electrochemical impedance spectroscopy (EIS) modelling study, we have established the contribution of the faradaic reaction as the major charge-injection contributor within the safe neural stimulation potential window of ±0.6 V vs. Ag|AgCl. We have also established the reversibility of the charge-injection process for sputtered RuOx film, by applying constant charge-per-phase current stimulations at different pulse widths, and by comparing the magnitudes of the leading and trailing access voltages during voltage transient measurements. Finally, the impedance of the sputtered RuOx film was found to be reasonably comparable in both its oxidized and reduced states, although the electronic contribution from the capacitive double-layer was found to be slightly higher for the completely oxidized film around 0.6 V than for its reduced counterpart around −0.6 V.

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Rui, Yuefeng, Jingquan Liu, Yajun Wang, and Chunsheng Yang. "Parylene-based implantable Pt-black coated flexible 3-D hemispherical microelectrode arrays for improved neural interfaces." Microsystem Technologies 17, no. 3 (March 2011): 437–42. http://dx.doi.org/10.1007/s00542-011-1279-x.

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Xiao, Guihua, Yilin Song, Yu Zhang, Yu Xing, Shengwei Xu, Mixia Wang, Junbo Wang, Deyong Chen, Jian Chen, and Xinxia Cai. "Dopamine and Striatal Neuron Firing Respond to Frequency-Dependent DBS Detected by Microelectrode Arrays in the Rat Model of Parkinson’s Disease." Biosensors 10, no. 10 (September 28, 2020): 136. http://dx.doi.org/10.3390/bios10100136.

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(1) Background: Deep brain stimulation (DBS) is considered as an efficient treatment method for alleviating motor symptoms in Parkinson’s disease (PD), while different stimulation frequency effects on the specific neuron patterns at the cellular level remain unknown. (2) Methods: In this work, nanocomposites-modified implantable microelectrode arrays (MEAs) were fabricated to synchronously record changes of dopamine (DA) concentration and striatal neuron firing in the striatum during subthalamic nucleus DBS, and different responses of medium spiny projecting neurons (MSNs) and fast spiking interneurons (FSIs) to DBS were analyzed. (3) Results: DA concentration and striatal neuron spike firing rate showed a similar change as DBS frequency changed from 10 to 350 Hz. Note that the increases in DA concentration (3.11 ± 0.67 μM) and neural spike firing rate (15.24 ± 2.71 Hz) were maximal after the stimulation at 100 Hz. The MSNs firing response to DBS was significant, especially at 100 Hz, while the FSIs remained stable after various stimulations. (4) Conclusions: DBS shows the greatest regulatory effect on DA concentration and MSNs firing rate at 100 Hz stimulation. This implantable MEA in the recording of the neurotransmitter and neural spike pattern response to DBS provides a new insight to understand the mechanism of PD at the cellular level.

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Saggese, Gerardo, and Antonio Giuseppe Maria Strollo. "A Low Power 1024-Channels Spike Detector Using Latch-Based RAM for Real-Time Brain Silicon Interfaces." Electronics 10, no. 24 (December 9, 2021): 3068. http://dx.doi.org/10.3390/electronics10243068.

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High-density microelectrode arrays allow the neuroscientist to study a wider neurons population, however, this causes an increase of communication bandwidth. Given the limited resources available for an implantable silicon interface, an on-fly data reduction is mandatory to stay within the power/area constraints. This can be accomplished by implementing a spike detector aiming at sending only the useful information about spikes. We show that the novel non-linear energy operator called ASO in combination with a simple but robust noise estimate, achieves a good trade-off between performance and consumption. The features of the investigated technique make it a good candidate for implantable BMIs. Our proposal is tested both on synthetic and real datasets providing a good sensibility at low SNR. We also provide a 1024-channels VLSI implementation using a Random-Access Memory composed by latches to reduce as much as possible the power consumptions. The final architecture occupies an area of 2.3 mm2, dissipating 3.6 µW per channels. The comparison with the state of art shows that our proposal finds a place among other methods presented in literature, certifying its suitability for BMIs.

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Amini, Shahram. "O021 / #592 HIERARCHICAL SURFACE RESTRUCTURING: A NOVEL TECHNOLOGY FOR NEXT GENERATION IMPLANTABLE NEURAL INTERFACING ELECTRODES AND MICROELECTRODE ARRAYS." Neuromodulation: Technology at the Neural Interface 25, no. 7 (October 2022): S50—S51. http://dx.doi.org/10.1016/j.neurom.2022.08.058.

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Yi, Wenwen, Chaoyang Chen, Zhaoying Feng, Yong Xu, Chengpeng Zhou, Nirul Masurkar, John Cavanaugh, and Mark Ming-Cheng Cheng. "A flexible and implantable microelectrode arrays using high-temperature grown vertical carbon nanotubes and a biocompatible polymer substrate." Nanotechnology 26, no. 12 (March 6, 2015): 125301. http://dx.doi.org/10.1088/0957-4484/26/12/125301.

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Jeakle, Eleanor N., Justin R. Abbott, Joshua O. Usoro, Yupeng Wu, Pegah Haghighi, Rahul Radhakrishna, Brandon S. Sturgill, et al. "Chronic Stability of Local Field Potentials Using Amorphous Silicon Carbide Microelectrode Arrays Implanted in the Rat Motor Cortex." Micromachines 14, no. 3 (March 19, 2023): 680. http://dx.doi.org/10.3390/mi14030680.

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Implantable microelectrode arrays (MEAs) enable the recording of electrical activity of cortical neurons, allowing the development of brain-machine interfaces. However, MEAs show reduced recording capabilities under chronic conditions, prompting the development of novel MEAs that can improve long-term performance. Conventional planar, silicon-based devices and ultra-thin amorphous silicon carbide (a-SiC) MEAs were implanted in the motor cortex of female Sprague–Dawley rats, and weekly anesthetized recordings were made for 16 weeks after implantation. The spectral density and bandpower between 1 and 500 Hz of recordings were compared over the implantation period for both device types. Initially, the bandpower of the a-SiC devices and standard MEAs was comparable. However, the standard MEAs showed a consistent decline in both bandpower and power spectral density throughout the 16 weeks post-implantation, whereas the a-SiC MEAs showed substantially more stable performance. These differences in bandpower and spectral density between standard and a-SiC MEAs were statistically significant from week 6 post-implantation until the end of the study at 16 weeks. These results support the use of ultra-thin a-SiC MEAs to develop chronic, reliable brain-machine interfaces.

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Lu, Botao, Penghui Fan, Yiding Wang, Yuchuan Dai, Jingyu Xie, Gucheng Yang, Fan Mo, et al. "Neuronal Electrophysiological Activities Detection of Defense Behaviors Using an Implantable Microelectrode Array in the Dorsal Periaqueductal Gray." Biosensors 12, no. 4 (March 25, 2022): 193. http://dx.doi.org/10.3390/bios12040193.

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Defense is the basic survival mechanism of animals when facing dangers. Previous studies have shown that the midbrain periaqueduct gray (PAG) was essential for the production of defense responses. However, the correlation between the endogenous neuronal activities of the dorsal PAG (dPAG) and different defense behaviors was still unclear. In this article, we designed and manufactured microelectrode arrays (MEAs) whose detection sites were arranged to match the shape and position of dPAG in rats, and modified it with platinum-black nanoparticles to improve the detection performance. Subsequently, we successfully recorded the electrophysiological activities of dPAG neurons via designed MEAs in freely behaving rats before and after exposure to the potent analog of predator odor 2-methyl-2-thiazoline (2-MT). Results demonstrated that 2-MT could cause strong innate fear and a series of defensive behaviors, accompanied by the significantly increased average firing rate and local field potential (LFP) power of neurons in dPAG. We also observed that dPAG participated in different defense behaviors with different degrees of activation, which was significantly stronger in the flight stage. Further analysis showed that the neuronal activities of dPAG neurons were earlier than flight, and the intensity of activation was inversely proportional to the distance from predator odor. Overall, our results indicate that dPAG neuronal activities play a crucial role in controlling different types of predator odor-evoked innate fear/defensive behaviors, and provide some guidance for the prediction of defense behavior.

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Caldwell, Ryan, Himadri Mandal, Rohit Sharma, Florian Solzbacher, Prashant Tathireddy, and Loren Rieth. "Analysis of Al2O3—parylene C bilayer coatings and impact of microelectrode topography on long term stability of implantable neural arrays." Journal of Neural Engineering 14, no. 4 (May 31, 2017): 046011. http://dx.doi.org/10.1088/1741-2552/aa69d3.

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Wu, Bingchen, Elisa Castagnola, and Xinyan Tracy Cui. "Zwitterionic Polymer Coated and Aptamer Functionalized Flexible Micro-Electrode Arrays for In Vivo Cocaine Sensing and Electrophysiology." Micromachines 14, no. 2 (January 27, 2023): 323. http://dx.doi.org/10.3390/mi14020323.

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The number of people aged 12 years and older using illicit drugs reached 59.3 million in 2020, among which 5.2 million are cocaine users based on the national data. In order to fully understand cocaine addiction and develop effective therapies, a tool is needed to reliably measure real-time cocaine concentration and neural activity in different regions of the brain with high spatial and temporal resolution. Integrated biochemical sensing devices based upon flexible microelectrode arrays (MEA) have emerged as a powerful tool for such purposes; however, MEAs suffer from undesired biofouling and inflammatory reactions, while those with immobilized biologic sensing elements experience additional failures due to biomolecule degradation. Aptasensors are powerful tools for building highly selective sensors for analytes that have been difficult to detect. In this work, DNA aptamer-based electrochemical cocaine sensors were integrated on flexible MEAs and protected with an antifouling zwitterionic poly (sulfobetaine methacrylate) (PSB) coating, in order to prevent sensors from biofouling and degradation by the host tissue. In vitro experiments showed that without the PSB coating, both adsorption of plasma protein albumin and exposure to DNase-1 enzyme have detrimental effects on sensor performance, decreasing signal amplitude and the sensitivity of the sensors. Albumin adsorption caused a 44.4% sensitivity loss, and DNase-1 exposure for 24 hr resulted in a 57.2% sensitivity reduction. The PSB coating successfully protected sensors from albumin fouling and DNase-1 enzyme digestion. In vivo tests showed that the PSB coated MEA aptasensors can detect repeated cocaine infusions in the brain for 3 hrs after implantation without sensitivity degradation. Additionally, the same MEAs can record electrophysiological signals at different tissue depths simultaneously. This novel flexible MEA with integrated cocaine sensors can serve as a valuable tool for understanding the mechanisms of cocaine addiction, while the PSB coating technology can be generalized to improve all implantable devices suffering from biofouling and inflammatory host responses.

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Narayana, V. Lakshman, and A. Peda Gopi. "Enterotoxigenic Escherichia Coli Detection Using the Design of a Biosensor." Journal of New Materials for Electrochemical Systems 23, no. 3 (September 30, 2020): 164–66. http://dx.doi.org/10.14447/jnmes.v23i3.a02.

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The food industry and clinical analysis, among other sectors, require the development of techniques and devices that detect pathogens, while the development of implantable devices needs biocompatible materials with low degradation in biological environment to increase the lifetime of the device. Throughout this work, hydrogenated amorphous silicon-carbon alloy is proposed, obtained, characterized and incorporated into the development of a proposed interdigitated microelectrode array (PIMA) to capture the bacteria of enterotoxigenic Escherichia coli (E. coli, ETEC). a-SixC1-x:H is obtained by the technique of plasma-enhanced chemical vapor deposition (PECVD) using methane and silane as precursor gases under high hydrogen dilution and low power density in order to improve its biocompatibility. Functionally the PIMA is a transducer based on electrical impedance, namely the capture of E. coli bacteria causes changes in the electrical properties of the medium between and on the microelectrodes of the array, which are associated with changes in electrical impedance. The simulations were made with the purpose of knowing the operation that the PIMA would have under operating conditions (with bacterial environment) and of analyzing the design aspects that could affect or increase the sensitivity of the array.

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Guan, S., J. Wang, X. Gu, Y. Zhao, R. Hou, H. Fan, L. Zou, et al. "Elastocapillary self-assembled neurotassels for stable neural activity recordings." Science Advances 5, no. 3 (March 2019): eaav2842. http://dx.doi.org/10.1126/sciadv.aav2842.

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Implantable neural probes that are mechanically compliant with brain tissue offer important opportunities for stable neural interfaces in both basic neuroscience and clinical applications. Here, we developed a Neurotassel consisting of an array of flexible and high–aspect ratio microelectrode filaments. A Neurotassel can spontaneously assemble into a thin and implantable fiber through elastocapillary interactions when withdrawn from a molten, tissue-dissolvable polymer. Chronically implanted Neurotassels elicited minimal neuronal cell loss in the brain and enabled stable activity recordings of the same population of neurons in mice learning to perform a task. Moreover, Neurotassels can be readily scaled up to 1024 microelectrode filaments, each with a neurite-scale cross-sectional footprint of 3 × 1.5 μm2, to form implantable fibers with a total diameter of ~100 μm. With their ultrasmall sizes, high flexibility, and scalability, Neurotassels offer a new approach for stable neural activity recording and neuroprosthetics.

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Ferrea, E., L. Suriya-Arunroj, D. Hoehl, U. Thomas, and A. Gail. "Implantable computer-controlled adaptive multielectrode positioning system." Journal of Neurophysiology 119, no. 4 (April 1, 2018): 1471–84. http://dx.doi.org/10.1152/jn.00504.2017.

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Acute neuronal recordings performed with metal microelectrodes in nonhuman primates allow investigating the neural substrate of complex cognitive behaviors. Yet the daily reinsertion and positioning of the electrodes prevents recording from many neurons simultaneously, limiting the suitability of these types of recordings for brain-computer interface applications or for large-scale population statistical methods on a trial-by-trial basis. In contrast, chronically implanted multielectrode arrays offer the opportunity to record from many neurons simultaneously, but immovable electrodes prevent optimization of the signal during and after implantation and cause the tissue response to progressively impair the transduced signal quality, thereby limiting the number of different neurons that can be recorded over the lifetime of the implant. Semichronically implanted matrices of electrodes, instead, allow individually movable electrodes in depth and achieve higher channel count compared with acute methods, hence partially overcoming these limitations. Existing semichronic systems with higher channel count lack computerized control of electrode movements, leading to limited user-friendliness and uncertainty in depth positioning. Here we demonstrate a chronically implantable adaptive multielectrode positioning system with detachable drive for computerized depth adjustment of individual electrodes over several millimeters. This semichronic 16-channel system is designed to optimize the simultaneous yield of units in an extended period following implantation since the electrodes can be independently depth adjusted with minimal effort and their signal quality continuously assessed. Importantly, the electrode array is designed to remain within a chronic recording chamber for a prolonged time or can be used for acute recordings with high signal-to-noise ratio in the cerebral cortex of nonhuman primates. NEW & NOTEWORTHY We present a 16-channel motorized, semichronic multielectrode array with individually depth-adjustable electrodes to record in the cerebral cortex of nonhuman primates. Compared with fixed-geometry arrays, this system allows repeated reestablishing of single neuron isolation. Compared with manually adjustable arrays it benefits from computer-controlled positioning. Compared with motorized semichronic systems it allows higher channel counts due to a robotic single actuator approach. Overall the system is designed to optimize the simultaneous yield of units over the course of implantation.

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Sui, Xiao Hong, Fei Tan, and Qiu Shi Ren. "Electrical Characteristics of a Stimulating Microelectrode-Electrolyte Interface." Key Engineering Materials 483 (June 2011): 690–93. http://dx.doi.org/10.4028/www.scientific.net/kem.483.690.

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The electrochemical stability of the implantable microelectrode array is one of the most important considerations for effective neural stimulation. Electrical characteristics of a polyimide-based platinum microelectrode-electrolyte interface were presented in this paper, which could help determine some stimulus parameters in neural restoration applications. The novel 16-channel Φ-200 μm polyimide-based platinum thin-film flexible microelectrode array was micro-fabricated and an appropriate circuit model of the electrode-electrolyte interface was adopted with three different components of series capacitance Cs, series resistance Rs and Faradic resistance Rf. By using sinusoidal testing signals, the respective changing relationships between the former two components and modulus of impedance Z vs. applied current density were tested in vitro at 37.8°C. The tested results showed that the magnitude of Cs and Rs maintained respective constant values at the low stimulating current density, while with current density gradually increasing, Cs increased and Rs decreased sharply. The tested electrochemical impedance in vitro decreased with the increasing frequency.

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Li, Szu-Ying, Hsin-Yi Tseng, Bo-Wei Chen, Yu-Chun Lo, Huai-Hsuan Shao, Yen-Ting Wu, Ssu-Ju Li, et al. "Proof of Concept for Sustainable Manufacturing of Neural Electrode Array for In Vivo Recording." Biosensors 13, no. 2 (February 16, 2023): 280. http://dx.doi.org/10.3390/bios13020280.

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Increasing requirements for neural implantation are helping to expand our understanding of nervous systems and generate new developmental approaches. It is thanks to advanced semiconductor technologies that we can achieve the high-density complementary metal-oxide-semiconductor electrode array for the improvement of the quantity and quality of neural recordings. Although the microfabricated neural implantable device holds much promise in the biosensing field, there are some significant technological challenges. The most advanced neural implantable device relies on complex semiconductor manufacturing processes, which are required for the use of expensive masks and specific clean room facilities. In addition, these processes based on a conventional photolithography technique are suitable for mass production, which is not applicable for custom-made manufacturing in response to individual experimental requirements. The microfabricated complexity of the implantable neural device is increasing, as is the associated energy consumption, and corresponding emissions of carbon dioxide and other greenhouse gases, resulting in environmental deterioration. Herein, we developed a fabless fabricated process for a neural electrode array that was simple, fast, sustainable, and customizable. An effective strategy to produce conductive patterns as the redistribution layers (RDLs) includes implementing microelectrodes, traces, and bonding pads onto the polyimide (PI) substrate by laser micromachining techniques combined with the drop coating of the silver glue to stack the laser grooving lines. The process of electroplating platinum on the RDLs was performed to increase corresponding conductivity. Sequentially, Parylene C was deposited onto the PI substrate to form the insulation layer for the protection of inner RDLs. Following the deposition of Parylene C, the via holes over microelectrodes and the corresponding probe shape of the neural electrode array was also etched by laser micromachining. To increase the neural recording capability, three-dimensional microelectrodes with a high surface area were formed by electroplating gold. Our eco-electrode array showed reliable electrical characteristics of impedance under harsh cyclic bending conditions of over 90 degrees. For in vivo application, our flexible neural electrode array demonstrated more stable and higher neural recording quality and better biocompatibility as well during the 2-week implantation compared with those of the silicon-based neural electrode array. In this study, our proposed eco-manufacturing process for fabricating the neural electrode array reduced 63 times of carbon emissions compared to the traditional semiconductor manufacturing process and provided freedom in the customized design of the implantable electronic devices as well.

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Beygi, Mohammad, John T. Bentley, Christopher L. Frewin, Cary A. Kuliasha, Arash Takshi, Evans K. Bernardin, Francesco La Via, and Stephen E. Saddow. "Fabrication of a Monolithic Implantable Neural Interface from Cubic Silicon Carbide." Micromachines 10, no. 7 (June 29, 2019): 430. http://dx.doi.org/10.3390/mi10070430.

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One of the main issues with micron-sized intracortical neural interfaces (INIs) is their long-term reliability, with one major factor stemming from the material failure caused by the heterogeneous integration of multiple materials used to realize the implant. Single crystalline cubic silicon carbide (3C-SiC) is a semiconductor material that has been long recognized for its mechanical robustness and chemical inertness. It has the benefit of demonstrated biocompatibility, which makes it a promising candidate for chronically-stable, implantable INIs. Here, we report on the fabrication and initial electrochemical characterization of a nearly monolithic, Michigan-style 3C-SiC microelectrode array (MEA) probe. The probe consists of a single 5 mm-long shank with 16 electrode sites. An ~8 µm-thick p-type 3C-SiC epilayer was grown on a silicon-on-insulator (SOI) wafer, which was followed by a ~2 µm-thick epilayer of heavily n-type (n+) 3C-SiC in order to form conductive traces and the electrode sites. Diodes formed between the p and n+ layers provided substrate isolation between the channels. A thin layer of amorphous silicon carbide (a-SiC) was deposited via plasma-enhanced chemical vapor deposition (PECVD) to insulate the surface of the probe from the external environment. Forming the probes on a SOI wafer supported the ease of probe removal from the handle wafer by simple immersion in HF, thus aiding in the manufacturability of the probes. Free-standing probes and planar single-ended test microelectrodes were fabricated from the same 3C-SiC epiwafers. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed on test microelectrodes with an area of 491 µm2 in phosphate buffered saline (PBS) solution. The measurements showed an impedance magnitude of 165 kΩ ± 14.7 kΩ (mean ± standard deviation) at 1 kHz, anodic charge storage capacity (CSC) of 15.4 ± 1.46 mC/cm2, and a cathodic CSC of 15.2 ± 1.03 mC/cm2. Current-voltage tests were conducted to characterize the p-n diode, n-p-n junction isolation, and leakage currents. The turn-on voltage was determined to be on the order of ~1.4 V and the leakage current was less than 8 μArms. This all-SiC neural probe realizes nearly monolithic integration of device components to provide a likely neurocompatible INI that should mitigate long-term reliability issues associated with chronic implantation.

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Swadlow, Harvey A., Yulia Bereshpolova, Tatiana Bezdudnaya, Monica Cano, and Carl R. Stoelzel. "A Multi-Channel, Implantable Microdrive System for Use With Sharp, Ultra-Fine “Reitboeck” Microelectrodes." Journal of Neurophysiology 93, no. 5 (May 2005): 2959–65. http://dx.doi.org/10.1152/jn.01141.2004.

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Arrays of closely spaced quartz-insulated, platinum-tungsten microelectrodes are widely used to obtain acute recordings from chronically prepared subjects. These electrodes have excellent recording characteristics and can be fabricated to a wide variety of tip specifications. Typically, in such experiments, electrodes are introduced into, and removed from, the brain on a daily basis and, over many months of study, hundreds of penetrations may be made through an intact dura. This procedure has benefits as well as problems and risks. For some experimental aims, it might be desirable to leave the microelectrodes within the brain so that the penetrations could be continued on subsequent days. This would allow a more thorough and systematic exploration of the neurons that lie along the trajectory of each of the closely aligned electrodes and would minimize risks and preparation time associated with daily electrode insertions. Here we present a means for achieving this aim using arrays of sharp, flexible Reitboeck electrodes of extremely fine diameter (40-μm shaft diameter, pulled and ground to a fine tip). We show that these electrodes retain their excellent recording characteristics and can remain under microdrive control within the brain for periods of many months and, in one remarkable case, for >4 years.

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Huang, Ting, Zhonghai Wang, Lina Wei, Mark Kindy, Yufeng Zheng, Tingfei Xi, and Bruce Z. Gao. "Microelectrode Array-evaluation of Neurotoxic Effects of Magnesium as an Implantable Biomaterial." Journal of Materials Science & Technology 32, no. 1 (January 2016): 89–96. http://dx.doi.org/10.1016/j.jmst.2015.08.009.

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Kim, Yong-Ho, Chungkeun Lee, Kang-Min Ahn, Myoungho Lee, and Yong-Jun Kim. "Robust and real-time monitoring of nerve regeneration using implantable flexible microelectrode array." Biosensors and Bioelectronics 24, no. 7 (March 2009): 1883–87. http://dx.doi.org/10.1016/j.bios.2008.09.034.

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Yoon, E., B. Koo, J. Wong, S. Elyahoodayan, J. D. Weiland, C. D. Lee, A. Petrossians, and E. Meng. "An implantable microelectrode array for chronic in vivo epiretinal stimulation of the rat retina." Journal of Micromechanics and Microengineering 30, no. 12 (October 17, 2020): 124001. http://dx.doi.org/10.1088/1361-6439/abbb7d.

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Trada, Hiren V., Venkat Vendra, Joseph P. Tinney, Fangping Yuan, Douglas J. Jackson, Kevin M. Walsh, and Bradley B. Keller. "Implantable thin-film porous microelectrode array (P-MEA) for electrical stimulation of engineered cardiac tissues." BioChip Journal 9, no. 2 (March 18, 2015): 85–94. http://dx.doi.org/10.1007/s13206-015-9201-8.

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Guo, Rui, and Jing Liu. "Implantable liquid metal-based flexible neural microelectrode array and its application in recovering animal locomotion functions." Journal of Micromechanics and Microengineering 27, no. 10 (September 13, 2017): 104002. http://dx.doi.org/10.1088/1361-6439/aa891c.

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Shan, Jin, Yilin Song, Yiding Wang, Penghui Fan, Botao Lu, Jinping Luo, Wei Xu, et al. "Highly Activated Neuronal Firings Monitored by Implantable Microelectrode Array in the Paraventricular Thalamus of Insomnia Rats." Sensors 23, no. 10 (May 10, 2023): 4629. http://dx.doi.org/10.3390/s23104629.

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Insomnia is a common sleep disorder around the world, which is harmful to people’s health, daily life, and work. The paraventricular thalamus (PVT) plays an essential role in the sleep–wake transition. However, high temporal-spatial resolution microdevice technology is lacking for accurate detection and regulation of deep brain nuclei. The means for analyzing sleep–wake mechanisms and treating sleep disorders are limited. To detect the relationship between the PVT and insomnia, we designed and fabricated a special microelectrode array (MEA) to record electrophysiological signals of the PVT for insomnia and control rats. Platinum nanoparticles (PtNPs) were modified onto an MEA, which caused the impedance to decrease and improved the signal-to-noise ratio. We established the model of insomnia in rats and analyzed and compared the neural signals in detail before and after insomnia. In insomnia, the spike firing rate was increased from 5.48 ± 0.28 spike/s to 7.39 ± 0.65 spike/s, and the power of local field potential (LFP) decreased in the delta frequency band and increased in the beta frequency band. Furthermore, the synchronicity between PVT neurons declined, and burst-like firing was observed. Our study found neurons of the PVT were more activated in the insomnia state than in the control state. It also provided an effective MEA to detect the deep brain signals at the cellular level, which conformed with macroscopical LFP and insomnia symptoms. These results laid the foundation for studying PVT and the sleep–wake mechanism and were also helpful for treating sleep disorders.

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Nazari, Hossein, Paulo Falabella, Lan Yue, James Weiland, and Mark S. Humayun. "Retinal Prostheses." Journal of VitreoRetinal Diseases 1, no. 3 (April 20, 2017): 204–13. http://dx.doi.org/10.1177/2474126417702067.

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Artificial vision is restoring sight by electrical stimulation of the visual system at the level of retina, optic nerve, lateral geniculate body, or occipital cortex. The development of artificial vision began with occipital cortex prosthesis; however, retinal prosthesis has advanced faster in recent years. Currently, multiple efforts are focused on finding the optimal approach for restoring vision through an implantable retinal microelectrode array system. Retinal prostheses function by stimulating the inner retinal neurons that survive retinal degeneration. In these devices, the visual information, gathered by a light detector, is transformed into controlled patterns of electrical pulses, which are in turn delivered to the surviving retinal neurons by an electrode array. Retinal prostheses are classified based on where the stimulating array is implanted (ie, epiretinal, subretinal, suprachoroidal, or episcleral). Recent regulatory approval of 2 retinal prostheses has greatly escalated interest in the potential of these devices to treat blindness secondary to outer retinal degeneration. This review will focus on the technical and operational features and functional outcomes of clinically tested retinal prostheses. We will discuss the major barriers and some of the more promising solutions to improve the outcomes of restoring vision with electrical retinal stimulation.

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Broche, Lionel M., Karla D. Bustamante, and Michael Pycraft Hughes. "An Algorithm for Tracking the Position and Velocity of Multiple Neuronal Signals Using Implantable Microelectrodes In Vivo." Micromachines 12, no. 11 (October 31, 2021): 1346. http://dx.doi.org/10.3390/mi12111346.

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Increasingly complex multi-electrode arrays for the study of neurons both in vitro and in vivo have been developed with the aim of tracking the conduction of neural action potentials across a complex interconnected network. This is usually performed through the use of electrodes to record from single or small groups of microelectrodes, and using only one electrode to monitor an action potential at any given time. More complex high-density electrode structures (with thousands of electrodes or more) capable of tracking action potential propagation have been developed but are not widely available. We have developed an algorithm taking data from clusters of electrodes positioned such that action potentials are detected by multiple sites, and using this to detect the location and velocity of action potentials from multiple neurons. The system has been tested by analyzing recordings from probes implanted into the locust nervous system, where recorded positions and velocities correlate well with the known physical form of the nerve.

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Marland, Jamie, Mark Gray, David Argyle, Ian Underwood, Alan Murray, and Mark Potter. "Post-Operative Monitoring of Intestinal Tissue Oxygenation Using an Implantable Microfabricated Oxygen Sensor." Micromachines 12, no. 7 (July 10, 2021): 810. http://dx.doi.org/10.3390/mi12070810.

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Anastomotic leakage (AL) is a common and dangerous post-operative complication following intestinal resection, causing substantial morbidity and mortality. Ischaemia in the tissue surrounding the anastomosis is a major risk-factor for AL development. Continuous tissue oxygenation monitoring during the post-operative recovery period would provide early and accurate early identification of AL risk. We describe the construction and testing of a miniature implantable electrochemical oxygen sensor that addresses this need. It consisted of an array of platinum microelectrodes, microfabricated on a silicon substrate, with a poly(2-hydroxyethyl methacrylate) hydrogel membrane to protect the sensor surface. The sensor was encapsulated in a biocompatible package with a wired connection to external instrumentation. It gave a sensitive and highly linear response to variations in oxygen partial pressure in vitro, although over time its sensitivity was partially decreased by protein biofouling. Using a pre-clinical in vivo pig model, acute intestinal ischaemia was robustly and accurately detected by the sensor. Graded changes in tissue oxygenation were also measurable, with relative differences detected more accurately than absolute differences. Finally, we demonstrated its suitability for continuous monitoring of tissue oxygenation at a colorectal anastomosis over a period of at least 45 h. This study provides evidence to support the development and use of implantable electrochemical oxygen sensors for post-operative monitoring of anastomosis oxygenation.

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Atta, Raghied Mohammed. "Increasing contact area of microelectrodes in implantable microchannel array system for peripheral nerve regenerative using metal deposited nanospheres." International Journal of Nano and Biomaterials 2, no. 1/2/3/4/5 (2009): 313. http://dx.doi.org/10.1504/ijnbm.2009.027727.

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Zhang, Song, Yilin Song, Mixia Wang, Zhiming Zhang, Xinyi Fan, Xianteng Song, Ping Zhuang, Feng Yue, Piu Chan, and Xinxia Cai. "A silicon based implantable microelectrode array for electrophysiological and dopamine recording from cortex to striatum in the non-human primate brain." Biosensors and Bioelectronics 85 (November 2016): 53–61. http://dx.doi.org/10.1016/j.bios.2016.04.087.

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Wei, Wenjing, Yilin Song, Xinyi Fan, Song Zhang, Li Wang, Shengwei Xu, Mixia Wang, and Xinxia Cai. "Simultaneous recording of brain extracellular glucose, spike and local field potential in real time using an implantable microelectrode array with nano-materials." Nanotechnology 27, no. 11 (February 12, 2016): 114001. http://dx.doi.org/10.1088/0957-4484/27/11/114001.

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Stutzki, Henrike, Florian Helmhold, Max Eickenscheidt, and Günther Zeck. "Subretinal electrical stimulation reveals intact network activity in the blind mouse retina." Journal of Neurophysiology 116, no. 4 (October 1, 2016): 1684–93. http://dx.doi.org/10.1152/jn.01095.2015.

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Retinal degeneration ( rd) leads to progressive photoreceptor cell death, resulting in vision loss. Stimulation of the inner-retinal neurons by neuroprosthetic implants is one of the clinically approved vision-restoration strategies, providing basic visual percepts to blind patients. However, little is understood as to what degree the degenerating retinal circuitry and the resulting aberrant hyperactivity may prevent the stimulation of physiological electrical activity. Therefore, we electrically stimulated ex vivo retinas from wild-type ( wt; C57BL/6J) and blind ( rd10 and rd1) mice using an implantable subretinal microchip and simultaneously recorded and analyzed the retinal ganglion cell (RGC) output with a flexible microelectrode array. We found that subretinal anodal stimulation of the rd10 retina and wt retina evoked similar spatiotemporal RGC-spiking patterns. In both retinas, electrically stimulated ON and a small percentage of OFF RGC responses were detected. The spatial selectivity of the retinal network to electrical stimuli reveals an intact underlying network with a median receptive-field center of 350 μm in both retinas. An antagonistic surround is activated by stimulation with large electrode fields. However, in rd10 and to a higher percentage, in rd1 retinas, rhythmic and spatially unconfined RGC patterns were evoked by anodal or by cathodal electrical stimuli. Our findings demonstrate that the surviving retinal circuitry in photoreceptor-degenerated retinas is preserved in a way allowing for the stimulation of temporally diverse and spatially confined RGC activity. Future vision restoration strategies can build on these results but need to avoid evoking the easily inducible rhythmic activity in some retinal circuits.

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Kim, Kangil, Seung-Ju Han, Chang-Hee Kim, and Sangmin Lee. "Implantable nanostructured microelectrode array with biphasic current stimulator for retinal prostheses." Technology and Health Care, February 23, 2023, 1–15. http://dx.doi.org/10.3233/thc-235001.

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BACKGROUND: In retinal prosthetic systems on multi-channel microelectrodes to effectively stimulate retinal neurons, the electrode-electrolyte interface impedance of a microelectrode should be minimized to drive sufficiently large current at a given supply voltage. OBJECTIVE: This paper presents the fabrication of the nanostructured microelectrode array with simplified fabrication and its characteristic evaluation using biphasic current stimulator. METHODS: The nanostructured microelectrodes with the base diameter of 25 μm, 50 μm, 75 μm are fabricated, and the maximum allowable current injection limits are measured to verify the estimated injection limit. Also, a biphasic stimulator has been fabricated using the 2-stage amplifier and 4 switches based on a stimulator cell. The adjustable load resistance is adopted to control between 5 kΩ to 20 kΩ, and the biphasic stimulator can drive the stimulation current between 50 uA and 200 uA. RESULTS: The proposed electrode-electrolyte interface impedance of the fabricated nanostructured microelectrode is 3178 Ω, 1218 Ω and 798.8 Ω for electrodes with diameter of 25 μm, 50 μm, 75 μm, respectively. CONCLUSION: This paper shows the advantages of the nanostructured microelectrode arrays for high resolution retinal prostheses, which could be a basic experiment for artificial retina research.

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Corbett, Scott, Joe Ketterl, and Tim Johnson. "Polymer-Based Microelectrode Arrays." MRS Proceedings 926 (2006). http://dx.doi.org/10.1557/proc-0926-cc06-02.

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ABSTRACTWe have developed flexible, polymer-based electrodes for potential medical applications including neural recording and stimulation. Using various combinations of liquid crystal polymer (LCP) substrates, implantable grade silicone and polyimide, we have developed and tested several prototype multi-layer polymer electrodes. We report here on two specific electrodes. In the first case, a multilayer electrode consisting of high-melt temperature liquid crystal polymer (LCP) material with patterned electrodes of sputter deposited and plated gold, laminated together with a lower-melt temperature LCP was produced. Iridium oxide was deposited on the exposed electrode sites to facilitate effective charge transfer for neural stimulation. The electrode was designed for acute implantation in a cat cochlea and contained 12 contacts, with a pitch of 200 microns. The small contact spacing allowed testing of electric field focusing techniques both in vitro and in vivo. We subjected the electrodes to electrical and mechanical tests to assess potential suitability as a long-term biomedical implant. Chronic electrical leakage testing indicated higher than desired ionic permeability of the low and high temperature LCP interface. In a second case we produced a mock circuit using high-melt LCP and medical grade low durometer silicone in place of the low-melt LCP as the interlayer adhesive. Mechanical and electrical testing of the hybrid design indicated the potential to fabricate cochlear electrodes containing up to 72 contacts with a footprint and mechanical performance similar or better than current commercially available cochlear implant arrays (containing up to 24 elements). Multi-layer polymer electrode technology offers the opportunity to create new electrodes with higher numbers of channels, offering improved performance in neural stimulation applications including cochlear implants, retinal arrays, deep brain stimulators and paraplegic remobilization devices.

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Lowe, Alexa, Safaa Hussain, Grace Xia, Ahsan Habib, and Ali Yanik. "Brain Computer Interfaces: Wireless Recording of Brain Signals with Electro-Plasmonic Nanoantenna." Journal of Student Research 11, no. 1 (February 28, 2022). http://dx.doi.org/10.47611/jsrhs.v11i1.2421.

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Brain-computer interfaces (BCIs) recording brain signals via implantable sensors aims to substitute, restore, improve, add, or enhance human functions. However, wiring requirements for power transfer and signal transmission, acute immune response to implanted electrodes, and the limited scalability of the ever-popular microelectrode arrays prevent wide adaptation of BCIs. Here, we show that electro-plasmonic nanoparticles, plasmonic nanoparticles loaded with an electrochromic polymer, can overcome the limitations of the conventional implantable microelectrode arrays as BCI probes. Much like radio frequency identification (RFIDs) tags that use backscattering for remote readout, electro-plasmonic nanoparticles report the spiking activity of neurons by modulating the input light and the re-radiated light spectrum. Our electro-plasmonic nanoantennas are non-invasive, wire-free, highly sensitive (field sensitivity up to 15.5%) and require no surgical implantation. We believe that electro-plasmonic neural probes can help usher in a new era of BCIs.

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Hejazi, Maryam, Wei Tong, Michael R. Ibbotson, Steven Prawer, and David J. Garrett. "Advances in Carbon-Based Microfiber Electrodes for Neural Interfacing." Frontiers in Neuroscience 15 (April 12, 2021). http://dx.doi.org/10.3389/fnins.2021.658703.

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Neural interfacing devices using penetrating microelectrode arrays have emerged as an important tool in both neuroscience research and medical applications. These implantable microelectrode arrays enable communication between man-made devices and the nervous system by detecting and/or evoking neuronal activities. Recent years have seen rapid development of electrodes fabricated using flexible, ultrathin carbon-based microfibers. Compared to electrodes fabricated using rigid materials and larger cross-sections, these microfiber electrodes have been shown to reduce foreign body responses after implantation, with improved signal-to-noise ratio for neural recording and enhanced resolution for neural stimulation. Here, we review recent progress of carbon-based microfiber electrodes in terms of material composition and fabrication technology. The remaining challenges and future directions for development of these arrays will also be discussed. Overall, these microfiber electrodes are expected to improve the longevity and reliability of neural interfacing devices.

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Sun, Yimin, Xulin Dong, Hu He, Yan Zhang, Kai Chi, Yun Xu, Muhammad Asif, et al. "2D carbon network arranged into high-order 3D nanotube arrays on a flexible microelectrode: integration into electrochemical microbiosensor devices for cancer detection." NPG Asia Materials 15, no. 1 (March 31, 2023). http://dx.doi.org/10.1038/s41427-022-00458-5.

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AbstractIn this work, we develop a new type of mesoporous 2D N, B, and P codoped carbon network (NBP-CNW) arranged into high-order 3D nanotube arrays (NTAs), which are wrapped onto a flexible carbon fiber microelectrode, and this microelectrode is employed as a high-performance carbon-based nanocatalyst for electrochemical biosensing. The NBP-CNW-NTAs synthesized by a facile, controllable, ecofriendly and sustainable template strategy using ionic liquids as precursors possess a high structural stability, large surface area, abundant active sites, and effective charge transport pathways, which dramatically improve their electrocatalytic activity and durability in the redox reaction of cancer biomarker H2O2. Benefiting from these unique structural merits, superb electrochemical activity and good biocompatibility, the NBP-CNW-NTAs-modified microelectrode demonstrates excellent sensing performance toward H2O2 and is embedded in a homemade microfluidic electrochemical biosensor chip for the real-time tracking of H2O2 secreted from different live cancer cells with or without radiotherapy treatment, which provides a new strategy for distinguishing the types of cancer cells and evaluating the radiotherapeutic efficacy of cancer cells. Furthermore, the functional microelectrode is integrated into an implantable probe for the in situ detection of surgically resected human specimens to distinguish cancer tissues from normal tissues. These will be of vital significance for cancer diagnoses and therapy in clinical practice.

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Journal articles on the topic 'Implantable microelectrode arrays'

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