Flexible optoelectrical neural implants

2021 ◽  
Author(s):  
Jay Reddy ◽  
Ibrahim Kimukin ◽  
Maya Lassiter ◽  
Zabir Ahmed ◽  
Mohammad H. Malekoshoaraie ◽  
...  
Keyword(s):  
Neural Implants

scholarly journals Recording site placement on planar silicon-based probes affects signal quality in acute neuronal recordings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Richárd Fiáth ◽  
Domokos Meszéna ◽  
Zoltán Somogyvári ◽  
Mihály Boda ◽  
Péter Barthó ◽  
...  
Keyword(s):  
Single Unit ◽  
Brain Activity ◽  
Amplitude Distribution ◽  
High Amplitude ◽  
Neural Implants ◽  
Recording Site ◽  
Significant Difference ◽  
Planar Silicon ◽  
Silicon Based ◽  
Unit Yield

AbstractMultisite, silicon-based probes are widely used tools to record the electrical activity of neuronal populations. Several physical features of these devices are designed to improve their recording performance. Here, our goal was to investigate whether the position of recording sites on the silicon shank might affect the quality of the recorded neural signal in acute experiments. Neural recordings obtained with five different types of high-density, single-shank, planar silicon probes from anesthetized rats were analyzed. Wideband data were filtered to extract spiking activity, then the amplitude distribution of samples and quantitative properties of the recorded brain activity (single unit yield, spike amplitude and isolation distance) were compared between sites located at different positions of the silicon shank, focusing particularly on edge and center sites. Edge sites outperformed center sites: for all five probe types there was a significant difference in the signal power computed from the amplitude distributions, and edge sites recorded significantly more large amplitude samples both in the positive and negative range. Although the single unit yield was similar between site positions, the difference in spike amplitudes was noticeable in the range corresponding to high-amplitude spikes. Furthermore, the advantage of edge sites slightly decreased with decreasing shank width. Our results might aid the design of novel neural implants in enhancing their recording performance by identifying more efficient recording site placements.

scholarly journals Reliability of Neural Implants—Effective Method for Cleaning and Surface Preparation of Ceramics

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 209
Author(s):  
Patrick Kiele ◽  
Jan Hergesell ◽  
Melanie Bühler ◽  
Tim Boretius ◽  
Gregg Suaning ◽  
...  
Keyword(s):  
Surface Preparation ◽  
Neural Implants ◽  
Implantable Medical Devices ◽  
Welding Flux ◽  
Extensive Evaluation ◽  
Surface Analysis Techniques ◽  
Key Factor ◽  
Ceramic Components ◽  
University College London ◽  
Cleaning Procedures

Neural implants provide effective treatment and diagnosis options for diseases where pharmaceutical therapies are missing or ineffective. These active implantable medical devices (AIMDs) are designed to remain implanted and functional over decades. A key factor for achieving reliability and longevity are cleaning procedures used during manufacturing to prevent failures associated with contaminations. The Implantable Devices Group (IDG) at University College London (UCL) pioneered an approach which involved a cocktail of reagents described as “Leslie’s soup”. This process proved to be successful but no extensive evaluation of this method and the cocktail’s ingredients have been reported so far. Our study addressed this gap by a comprehensive analysis of the efficacy of this cleaning method. Surface analysis techniques complemented adhesion strengths methods to identify residues of contaminants like welding flux, solder residues or grease during typical assembly processes. Quantitative data prove the suitability of “Leslie’s soup” for cleaning of ceramic components during active implant assembly when residual ionic contaminations were removed by further treatment with isopropanol and deionised water. Solder and flux contaminations were removed without further mechanical cleaning. The adhesive strength of screen-printed metalisation layers increased from 12.50 ± 3.83 MPa without initial cleaning to 21.71 ± 1.85 MPa. We conclude that cleaning procedures during manufacturing of AIMDs, especially the understanding of applicability and limitations, is of central importance for their reliable and longevity.

scholarly journals Electrode impedance analysis of chronic tungsten microwire neural implants: understanding abiotic vs. biotic contributions

2014 ◽  
Vol 7 ◽  
Author(s):  
Viswanath Sankar ◽  
Erin Patrick ◽  
Robert Dieme ◽  
Justin C. Sanchez ◽  
Abhishek Prasad ◽  
...  
Keyword(s):  
Impedance Analysis ◽  
Electrode Impedance ◽  
Neural Implants

Functionalized Carbon Nanotube Microfibers for Chronic Neural Implants

2021 ◽  
pp. 109370
Author(s):  
Elke K Buschbeck ◽  
Anh Duc Le ◽  
Carly Kelley ◽  
Md Abdul Hoque ◽  
Noe T Alvarez
Keyword(s):  
Carbon Nanotube ◽  
Neural Implants ◽  
Functionalized Carbon Nanotube

Fetal nondopaminergic neural implants in parkinsonian primates

1991 ◽  
Vol 74 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Krzysztof S. Bankiewicz ◽  
Robert J. Plunkett ◽  
David M. Jacobowitz ◽  
Irwin J. Kopin ◽  
Edward H. Oldfield
Keyword(s):  
Dopaminergic Neurons ◽  
Neural Implants ◽  
Behavioral Recovery ◽  
Foramen Of Monro ◽  
Caudate Nuclei ◽  
Content Type ◽  
Primate Brain ◽  
Brain Implants ◽  
Microsurgical Approach ◽  
Fine Print

✓ Implantation of fetal dopamine-containing tissue into preformed cavities in the caudate nucleus of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonian monkeys leads to behavioral recovery. Recovery may be related to two sources of dopamine: the grafted cells and/or the sprouted fibers from host dopaminergic neurons. The authors undertook this study to determine whether behavioral recovery requires release of dopamine by the implanted tissue, and to establish if nondopaminergic fetal central nervous system implants can induce sprouting of dopamine fibers in the primate brain and cause behavioral recovery. Rhesus monkeys with MPTP-induced hemiparkinsonism or full parkinsonism and a stable neurological deficit were used for this study. Cavities were created in the caudate nuclei anterior to the foramen of Monro via an open microsurgical approach. Fetal cerebellum or spinal cord was implanted into the preformed cavities of three monkeys. Control parkinsonian monkeys showed no recovery. However, implant-induced improvement was stable for up to 6 months after implantation. Sprouted dopaminergic fibers oriented from the ventral striatum and nucleus accumbens were found in the area of the tissue implant in the animals that received fetal grafts but were not present in the control monkeys. It is concluded that brain implants do not need to contain dopamine to induce functional recovery in MPTP-induced parkinsonian primates. Implant-induced and trophic factor-mediated dopaminergic sprouting by the host brain plays a role in the behavioral recovery and may well be responsible for the clinical improvement seen in parkinsonian patients after brain implants.

Electromagnetic Effects of Wireless Transmission for Neural Implants

2014 ◽  
pp. 1-22 ◽  
Author(s):  
Kasun M. S. Thotahewa ◽  
Ahmed I. Al-Kalbani ◽  
Jean-Michel Redouté ◽  
Mehmet Rasit Yuce
Keyword(s):  
Wireless Transmission ◽  
Neural Implants ◽  
Electromagnetic Effects

scholarly journals Transfer Printing of Conductive Thin Films on PDMS with Soluble Substrates for Flexible Biosensors

2020 ◽  
Vol 2 (1) ◽  
pp. 47
Author(s):  
Steffen Hadeler ◽  
Sebastian Bengsch ◽  
Maren S. Prediger ◽  
Marc Christopher Wurz
Keyword(s):  
Physical Vapor Deposition ◽  
Electrochemical Impedance ◽  
Three Dimensional ◽  
Impedance Measurement ◽  
Water Soluble ◽  
Electrode Spacing ◽  
Conductive Layer ◽  
Electrode Structure ◽  
Neural Implants ◽  
The Individual

The resolution of commercially available electrocorticography (ECoG) electrodes is limited due to the large electrode spacing and, therefore, allows only a limited identification of the active nerve cell area. This paper describes a novel manufacturing process for neural implants with higher spatial resolution combining micro technological processes and Polydimethylsiloxane (PDMS) as the flexible, biocompatible material. The conductive electrode structure is deposited on a water-soluble transfer substrate by Physical Vapor Deposition (PVD) processes. Subsequently, the structure is contacted. Finally, the transfer to PDMS and dissolution of the transfer substrate takes place. In this way, high-resolution conductive structures can be produced on the PDMS. Transferred gold structures exhibit higher adhesion and conductivity than transferred platinum structures. The adhesion was improved by applying a silica surface modification to the conductive layer prior to transferring. Furthermore, the conductive layer is flexible, conductive up to an elongation of 10%, and resistant to sodium chloride solution, mimicking brain fluids. Using the introduced production process, an ECoG electrode was manufactured and characterized for its functionality in an electrochemical impedance measurement. Furthermore, the electrodes are flexible enough to adapt to different shapes. The transfer process can also be carried out in a three-dimensional mold to produce electrodes tailored to the individual patient.

Tissue-Compliant Neural Implants from Microfabricated Carbon Nanotube Multilayer Composite

ACS Nano ◽  
2013 ◽  
Vol 7 (9) ◽  
pp. 7619-7629 ◽  
Author(s):  
Huanan Zhang ◽  
Paras R. Patel ◽  
Zhixing Xie ◽  
Scott D. Swanson ◽  
Xueding Wang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Multilayer Composite ◽  
Neural Implants
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