scholarly journals A high-density carbon fiber neural recording array technology

2018 ◽  
Author(s):  
Travis L Massey ◽  
Samantha R Santacruz ◽  
Jason F Hou ◽  
Kristofer SJ Pister ◽  
Jose M Carmena ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Large Scale ◽  
Biological Response ◽  
Electrode Array ◽  
Neural Recording ◽  
Implanted Electrodes ◽  
Out Of Plane ◽  
Electrode Pitch ◽  
Isotropically Conductive Adhesive

Abstract.Objective: Microwire and Utah-style neural recording arrays are the predominant devices used for cortical neural recording, but the implanted electrodes cause a significant adverse biological response and suffer from well-studied performance degradation. Recent work has demonstrated that carbon fiber electrodes do not elicit this same adverse response, but these existing designs are not practically scalable to hundreds or thousands of recording sites. We present technology that overcomes these issues while additionally providing fine electrode pitch for spatial oversampling.Approach: We present a 32-channel carbon fiber monofilament-based intracortical neural recording array fabricated through a combination of bulk silicon microfabrication processing and microassembly. This device represents the first truly two-dimensional carbon fiber neural recording array. The density, channel count, and size scale of this array are enabled by an out-of-plane microassembly technique in which individual fibers are inserted through metallized and isotropically conductive adhesive-filled holes in an oxide-passivated microfabricated silicon substrate.Main results: Five-micron diameter fibers are spaced at a pitch of 38 microns, four times denser than state of the art one-dimensional arrays. The fine diameter of the carbon fibers affords both minimal cross-section and nearly three orders of magnitude greater lateral compliance than standard tungsten microwires. Typical 1 kHz impedances are on the order of hundreds of kiloohms, and successful in vivo recording is demonstrated in the motor cortex of a rat. 22 total units are recorded on 20 channels, with unit SNR ranging from 0.85 to 4.2.Significance: This is the highest density microwire-style electrode array to date, and this fabrication technique is scalable to a larger number of electrodes and allows for the potential future integration of microelectronics. Large-scale carbon fiber neural recording arrays are a promising technology for reducing the inflammatory response and increasing the information density, particularly in neural recording applications where microwire arrays are already used.

scholarly journals A mm-Sized Free-Floating Wireless Implantable Opto-Electro Stimulation Device

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 621
Author(s):  
Yaoyao Jia ◽  
Yan Gong ◽  
Arthur Weber ◽  
Wen Li ◽  
Maysam Ghovanloo
Keyword(s):  
Electrical Stimulation ◽  
Large Scale ◽  
Electrode Array ◽  
Cmos Process ◽  
Optical Stimulation ◽  
In Vivo Experiments ◽  
Stimulation Mode ◽  
Shift Keying ◽  
On Chip

Towards a distributed neural interface, consisting of multiple miniaturized implants, for interfacing with large-scale neuronal ensembles over large brain areas, this paper presents a mm-sized free-floating wirelessly-powered implantable opto-electro stimulation (FF-WIOS2) device equipped with 16-ch optical and 4-ch electrical stimulation for reconfigurable neuromodulation. The FF-WIOS2 is wirelessly powered and controlled through a 3-coil inductive link at 60 MHz. The FF-WIOS2 receives stimulation parameters via on-off keying (OOK) while sending its rectified voltage information to an external headstage for closed-loop power control (CLPC) via load-shift-keying (LSK). The FF-WIOS2 system-on-chip (SoC), fabricated in a 0.35-µm standard CMOS process, employs switched-capacitor-based stimulation (SCS) architecture to provide large instantaneous current needed for surpassing the optical stimulation threshold. The SCS charger charges an off-chip capacitor up to 5 V at 37% efficiency. At the onset of stimulation, the capacitor delivers charge with peak current in 1.7–12 mA range to a micro-LED (µLED) array for optical stimulation or 100–700 μA range to a micro-electrode array (MEA) for biphasic electrical stimulation. Active and passive charge balancing circuits are activated in electrical stimulation mode to ensure stimulation safety. In vivo experiments conducted on three anesthetized rats verified the efficacy of the two stimulation mechanisms. The proposed FF-WIOS2 is potentially a reconfigurable tool for performing untethered neuromodulation.

scholarly journals Enhanced out of Plane Electrical Conductivity in Polymer Composites Induced by CO2 Laser Irradiation of Carbon Fibers

2020 ◽  
Vol 10 (10) ◽  
pp. 3561
Author(s):  
Anastasios Karakassides ◽  
Angeliki Karakassides ◽  
Michaella Konstantinidou ◽  
Alkiviadis S. Paipetis ◽  
Pagona Papakonstantinou
Keyword(s):  
Electrical Conductivity ◽  
Carbon Fiber ◽  
Co2 Laser ◽  
Large Scale ◽  
Cost Effective ◽  
High Volume ◽  
Resin Matrix ◽  
Reinforced Polymer ◽  
Out Of Plane ◽  
Cfrp Composite

The creation of a hierarchical interface between the carbon fiber (CF) and the epoxy resin matrix of fiber-reinforced polymer (CFRP) composites has become an effective strategy for introducing multifunctional properties. Although the efficacy of many hierarchical interfaces has been established in lab-scale, their production is not amenable to high-volume, continuous, cost effective fiber production, which is required for the large-scale commercialization of composites. This work investigates the use of commercially available CO2 laser as a means of nano-structuring the surface of carbon fiber (CF) tows in an incessant throughput procedure. Even though the single carbon fiber tensile strength measurements showed a decrease up to 68% for the exposed CFs, the electrical conductivity exhibited an increment up to 18.4%. Furthermore, results on laminates comprised of irradiated unidirectional CF cloth, demonstrated an enhancement in out of plane electrical conductivity up to 43%, while preserved the Mode-I interlaminar fracture toughness of the composite, showing the potential for multifunctionality. This work indicates that the laser-induced graphitization of the CF surface can act as an interface for fast and cost-effective manufacturing of multifunctional CFRP composite materials.

scholarly journals A carbon-fiber electrode array for long-term neural recording

2013 ◽  
Vol 10 (4) ◽  
pp. 046016 ◽  
Author(s):  
Grigori Guitchounts ◽  
Jeffrey E Markowitz ◽  
William A Liberti ◽  
Timothy J Gardner
Keyword(s):  
Carbon Fiber ◽  
Electrode Array ◽  
Neural Recording ◽  
Carbon Fiber Electrode ◽  
Fiber Electrode

scholarly journals Biologically active recombinant carp LH as a spawning-inducing agent for carp

2017 ◽  
Vol 232 (3) ◽  
pp. 391-402 ◽  
Author(s):  
Joseph Aizen ◽  
Lian Hollander-Cohen ◽  
Michal Shpilman ◽  
Berta Levavi-Sivan
Keyword(s):  
Large Scale ◽  
Biological Response ◽  
Biologically Active ◽  
Dopamine Antagonist ◽  
Dependent Manner ◽  
Single Chain ◽  
Terminal Part ◽  
Α Subunit ◽  
Subsequent Decrease

Currently, spawning is induced in carp species by carp pituitary extract (CPE) and a combination of synthetic agonist of GnRH combined with a dopamine antagonist. The main goal of this study was the production of recombinant gonadotropins (GtHs) on a large scale to serve as an alternative to currently used agents. We produced carp (c) recombinant (r) Lh as a single chain in the methylotrophic yeast Pichia pastoris. Lha subunit was joined with Lhb subunit with a flexible linker of three glycine–serine repeats and six Histidines to form a mature protein, the β-subunit formed the N-terminal part and the α-subunit formed the C-terminal part. The ability of the rcLh to elicit biological response was tested by in vivo stimulation of estradiol (E2) and 17α,20β-dihydroxy-4-pregnen-3-one (DHP) and by its in vivo potency to induce ovulation and spawning induction. rcLh tested in this work significantly enhanced both E2 and DHP secretion in a dose-dependent manner similar to the results obtained with CPE. E2 levels showed a moderate rise following the priming injection and a subsequent decrease during the rest of the trial. DHP levels were only increased after the resolving injection, approximately 5 h before spawning. At the highest dose of rcLh (350 µg/kg BW), the recombinant protein was more efficient than CPE in terms of both spawning success and fertilization rate. It is shown here that rcLh can elicit the secretion of DHP in vivo and actually trigger spawning. These novel findings introduce the potential of utilizing recombinant gonadotropins in aquaculture.

scholarly journals MEMS-Actuated Carbon Fiber Microelectrode for Neural Recording

2018 ◽  
Author(s):  
Rachel S. Zoll ◽  
Craig B. Schindler ◽  
Travis L. Massey ◽  
Daniel S. Drew ◽  
Michel M. Maharbiz ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Microelectrode Arrays ◽  
Biological Response ◽  
Neural Recording ◽  
Single Unit Activity ◽  
Recording Electrode ◽  
Carbon Fiber Microelectrode ◽  
Carbon Fiber Microelectrodes ◽  
Brain Phantom ◽  
Recording Electrodes

AbstractMicrowire and microelectrode arrays used for cortical neural recording typically consist of tens to hundreds of recording sites, but often only a fraction of these sites are in close enough proximity to firing neurons to record single-unit activity. Recent work has demonstrated precise, depth-controllable mechanisms for the insertion of single neural recording electrodes, but these methods are mostly only capable of inserting electrodes which elicit adverse biological response. We present an electrostatic-based actuator capable of inserting individual carbon fiber microelectrodes which elicit minimal to no adverse biological response. The device is shown to insert a carbon fiber recording electrode into an agar brain phantom and can record an artificial neural signal in saline. This technique provides a platform generalizable to many microwire-style recording electrodes.

Purification of the Antihemophilic Factor by Gel Filtration on Agarose

1969 ◽  
Vol 22 (03) ◽  
pp. 577-583 ◽  
Author(s):  
M.M.P Paulssen ◽  
A.C.M.G.B Wouterlood ◽  
H.L.M.A Scheffers
Keyword(s):  
Factor Viii ◽  
Plasma Proteins ◽  
Large Scale ◽  
Gel Filtration ◽  
Large Scale Preparation ◽  
Scale Preparation ◽  
Antihemophilic Factor

SummaryFactor VIII can be isolated from plasma proteins, including fibrinogen by chromatography on agarose. The best results were obtained with Sepharose 6B. Large scale preparation is also possible when cryoprecipitate is separated by chromatography. In most fractions containing factor VIII a turbidity is observed which may be due to the presence of chylomicrons.The purified factor VIII was active in vivo as well as in vitro.

The Effect of Active Site-inhibited Factor VIIa on Tissue Factor-initiated Coagulation Using Platelets before and after Aspirin Administration

1997 ◽  
Vol 78 (04) ◽  
pp. 1202-1208 ◽  
Author(s):  
Marianne Kjalke ◽  
Julie A Oliver ◽  
Dougald M Monroe ◽  
Maureane Hoffman ◽  
Mirella Ezban ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Active Site ◽  
Large Scale ◽  
Thrombin Generation ◽  
Factor Viia ◽  
Dependent Manner ◽  
Antithrombotic Agent ◽  
Before And After ◽  
Ic50 Values

SummaryActive site-inactivated factor VIIa has potential as an antithrombotic agent. The effects of D-Phe-L-Phe-L-Arg-chloromethyl ketone-treated factor VIla (FFR-FVIIa) were evaluated in a cell-based system mimicking in vivo initiation of coagulation. FFR-FVIIa inhibited platelet activation (as measured by expression of P-selectin) and subsequent large-scale thrombin generation in a dose-dependent manner with IC50 values of 1.4 ± 0.8 nM (n = 8) and 0.9 ± 0.7 nM (n = 7), respectively. Kd for factor VIIa binding to monocytes ki for FFR-FVIIa competing with factor VIIa were similar (11.4 ± 0.8 pM and 10.6 ± 1.1 pM, respectively), showing that FFR-FVIIa binds to tissue factor in the tenase complex with the same affinity as factor VIIa. Using platelets from volunteers before and after ingestion of aspirin (1.3 g), there were no significant differences in the IC50 values of FFR-FVIIa [after aspirin ingestion, the IC50 values were 1.7 ± 0.9 nM (n = 8) for P-selectin expression, p = 0.37, and 1.4 ± 1.3 nM (n = 7) for thrombin generation, p = 0.38]. This shows that aspirin treatment of platelets does not influence the inhibition of tissue factor-initiated coagulation by FFR-FVIIa, probably because thrombin activation of platelets is not entirely dependent upon expression of thromboxane A2.

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