scholarly journals Zebrafish Larva’s Response and Habituation to Electric Signal: Effects of Voltage, Current and Pulsation Studied in a Microfluidic Device

2021 ◽  
Author(s):  
Arezoo Khalili ◽  
Ellen van Wijngaarden ◽  
Georg Zoidl ◽  
Pouya Rezai
Keyword(s):  
Electric Current ◽  
Microfluidic Device ◽  
Voltage Drop ◽  
Light Stimulus ◽  
Beat Frequency ◽  
Phenotypic Characterization ◽  
Electric Signal ◽  
Electric Response ◽  
Current Direction ◽  
Electric Pulses

We previously showed that electric current can cause zebrafish larvae to move towards the anode pole along a microchannel. For a semi-mobile larva, we observed that zebrafish response to electricity depended on the current magnitude. The effects of electric signal direction, voltage magnitude and habituation to repeated exposures to electric pulses were not characterized. Here, this knowledge gap was addressed by exploiting these parameters in a microfluidic device with a head-trap to immobilize a zebrafish larva and a downstream chamber for tail movement and phenotypic characterization of response duration (RD) and tail beat frequency (TBF). We first assessed larvae’s response to electric current direction (at 3µA) and voltage magnitude. Changing the current direction significantly altered the RD and TBF with long and low-frequency responses seen when the anode was positioned at larvae’s tail. The electric voltage drop across the fish body had a significant effect on larvae’s locomotion with long RD and low TBF observed at 5.6V in the range of 1.3-9V. We also demonstrated that the zebrafish locomotor response to repeated 3µA current pulses diminished with dependency on the interstimulus interval. However, the diminished response was fully recovered after a 5-min resting period or introduction of a novel light stimulus (i.e. habituation-dishabituation strategy). Therefore, electric response suppression in zebrafish was attributed to the habituation as a form of non-associative learning. Our microfluidic platform has broad application potential in behavioral neuroscience to study cognitive phenotypes, fundamental studies on the biological roots of electric response, and pharmacological screening.

Phenotypic chemical and mutant screening of zebrafish larvae using an on-demand response to electric stimulation

2019 ◽  
Vol 11 (10) ◽  
pp. 373-383 ◽  
Author(s):  
Arezoo Khalili ◽  
Amir Reza Peimani ◽  
Nickie Safarian ◽  
Khaled Youssef ◽  
Georg Zoidl ◽  
...  
Keyword(s):  
Electric Stimulation ◽  
Gene Knockout ◽  
Beat Frequency ◽  
Movement Behavior ◽  
Model Organisms ◽  
Phenotypic Characterization ◽  
Electric Response ◽  
Zebrafish Larvae ◽  
On Demand ◽  
6 Hydroxydopamine

Abstract Behavioral responses of zebrafish larvae to environmental cues are important functional readouts that should be evoked on-demand and studied phenotypically in behavioral, genetical and developmental investigations. Very recently, it was shown that zebrafish larvae execute a voluntary and oriented movement toward the positive electrode of an electric field along a microchannel. Phenotypic characterization of this response was not feasible due to larva’s rapid movement along the channel. To overcome this challenge, a microfluidic device was introduced to partially immobilize the larva’s head while leaving its mid-body and tail unrestrained in a chamber to image motor behaviors in response to electric stimulation, hence achieving quantitative phenotyping of the electrically evoked movement in zebrafish larvae. The effect of electric current on the tail-beat frequency and response duration of 5–7 days postfertilization zebrafish larvae was studied. Investigations were also performed on zebrafish exposed to neurotoxin 6-hydroxydopamine and larvae carrying a pannexin1a (panx1a) gene knockout, as a proof of principle applications to demonstrate on-demand movement behavior screening in chemical and mutant assays. We demonstrated for the first time that 6-hydroxydopamine leads to electric response impairment, levodopa treatment rescues the response and panx1a is involved in the electrically evoked movement of zebrafish larvae. We envision that our technique is broadly applicable as a screening tool to quantitatively examine zebrafish larvae’s movements in response to physical and chemical stimulations in investigations of Parkinson’s and other neurodegenerative diseases, and as a tool to combine recent advances in genome engineering of model organisms to uncover the biology of electric response.

scholarly journals Microfluidic Devices for Behavioral Screening of Multiple Zebrafish Larvae: Design Investigation Process

2021 ◽  
Author(s):  
Arezoo Khalili ◽  
Ellen van Wijngaarden ◽  
khaled Youssef ◽  
Georg Zoidl ◽  
Pouya Rezai
Keyword(s):  
Microfluidic Device ◽  
Flow Behavior ◽  
Beat Frequency ◽  
Microfluidic Devices ◽  
Response Duration ◽  
Lessons Learned ◽  
Electric Signal ◽  
Testing Time ◽  
Multiple Parameters ◽  
Zebrafish Larvae

Microfluidic devices have been introduced for phenotypic screening of zebrafish larvae in both fundamental and pre-clinical research. One of the remaining challenges for the broad use of microfluidic devices is their limited throughput, especially in behavioural assays. Previously, we introduced the tail locomotion of a semi-mobile zebrafish larva evoked on-demand with electric signal in a microfluidic device. Here, we report the lessons learned for increasing the number of specimens from one to four larvae in this device. Multiple parameters including loading and testing time per fish and loading and orientation efficiencies were refined to optimize the performance of modified designs. Simulations of the flow and electric field within the final device provided insight into the flow behavior and functionality of traps when compared to previous single-larva devices. Outcomes led to a new design which decreased the testing time per larva by approximately 60%. Further, loading and orientation efficiencies increased by more than 80%. Critical behavioural parameters such as response duration and tail beat frequency were similar in both single and quadruple-fish devices. The optimized microfluidic device has significant advantages for greater throughput and efficiency when behavioral phenotyping is required in various applications, including chemical testing in toxicology and gene screening.

scholarly journals Negative Pressure Provides Simple and Stable Droplet Generation in a Flow-Focusing Microfluidic Device

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 662
Author(s):  
Nikita A. Filatov ◽  
Anatoly A. Evstrapov ◽  
Anton S. Bukatin
Keyword(s):  
Microfluidic Device ◽  
Negative Pressure ◽  
Low Cost ◽  
Control Valve ◽  
Droplet Microfluidics ◽  
Droplet Generation ◽  
Electric Signal ◽  
Absolute Pressure ◽  
Flow Focusing ◽  
Wide Range

Droplet microfluidics is an extremely useful and powerful tool for industrial, environmental, and biotechnological applications, due to advantages such as the small volume of reagents required, ultrahigh-throughput, precise control, and independent manipulations of each droplet. For the generation of monodisperse water-in-oil droplets, usually T-junction and flow-focusing microfluidic devices connected to syringe pumps or pressure controllers are used. Here, we investigated droplet-generation regimes in a flow-focusing microfluidic device induced by the negative pressure in the outlet reservoir, generated by a low-cost mini diaphragm vacuum pump. During the study, we compared two ways of adjusting the negative pressure using a compact electro-pneumatic regulator and a manual airflow control valve. The results showed that both types of regulators are suitable for the stable generation of monodisperse droplets for at least 4 h, with variations in diameter less than 1 µm. Droplet diameters at high levels of negative pressure were mainly determined by the hydrodynamic resistances of the inlet microchannels, although the absolute pressure value defined the generation frequency; however, the electro-pneumatic regulator is preferable and convenient for the accurate control of the pressure by an external electric signal, providing more stable pressure, and a wide range of droplet diameters and generation frequencies. The method of droplet generation suggested here is a simple, stable, reliable, and portable way of high-throughput production of relatively large volumes of monodisperse emulsions for biomedical applications.

scholarly journals Ion Acceleration Independent of the Electric Current Direction in Z-Pinch Plasma

2011 ◽  
Vol 6 ◽  
pp. 1201009-1201009 ◽  
Author(s):  
Mineyuki NISHIO ◽  
Hiroshi SAKUMA ◽  
Keiichi TAKASUGI
Keyword(s):  
Electric Current ◽  
Ion Acceleration ◽  
Current Direction ◽  
Pinch Plasma ◽  
Z Pinch

Effect of electric current pulse type on springback, microstructure, texture, and mechanical properties during V-bending of AA2024 aluminum alloy

2020 ◽  
pp. 1-36
Author(s):  
Nafiseh Mohammadtabar ◽  
Mohammad Bakhshi-jooybari ◽  
Hamid Gorji ◽  
Roohollah Jamaati ◽  
Jerzy A. Szpunar
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Electric Current ◽  
Current Pulse ◽  
Fiber Texture ◽  
Electric Current Pulse ◽  
Electric Pulses ◽  
Current Pulses ◽  
Electric Current Pulses ◽  
Pulse Type

Abstract The present work focused on the effect of the electric current pulse type on the springback, microstructure, texture, and mechanical properties during the V-bending process of AA2024 aluminum alloy. In order to investigate this effect, three different forming conditions including conventional V-bending and electrically assisted V-bending with square and sinusoidal pulses were considered. The results indicated that the amount of springback significantly decreased from 45.5° (for the sample formed via conventional V-bending) to 24° by applying the sinusoidal pulse. Microstructural observations revealed lower stored energy in the samples formed by electric current pulses which resulted in larger grain size compared to the samples formed without electric pulses. In addition, the result showed that the intensity of the (111)||BLD (bend line direction) fiber texture reduced after applying electric current pulses whereas it was very strong in the sample formed without electric pulses. It was suggested that the electric current pulses led to change the slip plane of the dislocations from {111} to {110} through cross slip. The applying electric current pulses decrease the ultimate tensile strength (UTS) from 471.1 MPa (for the conventional tensile test) to 448.0 and 426.7 MPa for the square and sinusoidal pulses, respectively. On the other hand, the electric pulses improved the formability of the AA2024 alloy owing to the activation of more slip systems, inhibition of dislocation pinning, the promotion of dislocation movement, and the acceleration of restoration mechanisms.

Simulation of the Electric Current Flow in Amorphous-Crystalline Ti2NiCu Alloy with Shape Memory Effect

2016 ◽  
Vol 845 ◽  
pp. 146-149
Author(s):  
Dmitriy S. Kuchin ◽  
Victor V. Koledov ◽  
Pavel V. Bogun ◽  
Peter V. Lega ◽  
Vedamanickam Sampath ◽  
...  
Keyword(s):  
Electric Current ◽  
Current Flow ◽  
Amorphous Matrix ◽  
Volume Fraction ◽  
Current Density Distribution ◽  
Heat Evolution ◽  
Equatorial Region ◽  
Joule Heat ◽  
Electric Pulses ◽  
Electric Current Flow

A new technique for the production of nanograined alloys from rapidly quenched amorphous ribbons by serial electric pulses has been proposed recently [1]. The present work involves a theoretical study of electric current flow in a nonhomogeneous Ti2NiCu alloy consisting of an amorphous matrix with a crystalline phase of spherical morphology embedded in it. The electric current density distribution was calculated in the vicinity of a spherical nucleus, which has an electrical resistance that is only 0.4 times that of the amorphous matrix. The calculation of Joule heat density was done in the nucleus and in the amorphous volume surrounding it. It was shown that during the current pulse the Joule heat evolution in nucleus exceeds one in equatorial region in matrix, but less than near the poles. The dependence of relative resistivity of nonhomogeneous amorphous-crystalline alloy on volume fraction of spherical crystalline nuclei was calculated

scholarly journals Direct Characterization of Motion-Dependent Parameters of Sperm in a Microfluidic Device: Proof of Principle

2013 ◽  
Vol 59 (3) ◽  
pp. 493-501 ◽  
Author(s):  
Yu-An Chen ◽  
Ken-Chao Chen ◽  
Vincent FS Tsai ◽  
Zi-Wei Huang ◽  
Ju-Ton Hsieh ◽  
...  
Keyword(s):  
Microfluidic Device ◽  
Sperm Quality ◽  
Semen Analysis ◽  
Beat Frequency ◽  
Sperm Concentration ◽  
Optical Methods ◽  
Voltage Source ◽  
Considerable Difficulty ◽  
Pulse Technique ◽  
Proof Of Principle

BACKGROUND Semen analysis is essential for evaluating male infertility. Besides sperm concentration, other properties, such as motility and morphology, are critical indicators in assessing sperm quality. Nevertheless, rapid and complete assessment of these measures still presents considerable difficulty and involves a range of complex issues. Here we present a microfluidic device capable of quantifying a range of properties of human sperm via the resistive pulse technique (RPT). METHODS An aperture, designed as a long channel, was used to allow the quantification of various properties as sperm swam through. RESULTS The time trace of the voltage drop across the aperture during sperm passage contained a wealth of information: the sperm volume was presented by the amplitude of the induced pulse, the swim velocity was evaluated via the duration, and the beat frequency was calculated from the voltage undulation superposed on the pulse signal. The RPT measurement of swim velocity and beat frequency showed a correlation with the same observation in a microscope (R2 = 0.94 and 0.70, respectively). CONCLUSIONS The proposed proof of principle enables substantial quantification of the motion-dependent properties of sperm. Because this approach requires only a current/voltage source and data analysis, it is economically advantageous compared with optical methods for characterizing sperm motion. Furthermore, this approach may be used to characterize sperm morphology.

Firing Activity of the Weakly-Electric Fish Marcusenius Macrolepidotus (Mormyridae, Teleostei): Logarithmic Repartition of Inter-Pulse Intervals, and Sequential Inequality Testing

Behaviour ◽  
1989 ◽  
Vol 109 (3-4) ◽  
pp. 258-283 ◽  
Author(s):  
Christian Graff
Keyword(s):  
Parametric Method ◽  
Electric Activity ◽  
Weakly Electric Fish ◽  
Electric Signal ◽  
Pulse Interval ◽  
Neural Firing ◽  
Firing Activity ◽  
Electric Pulses ◽  
Mormyrid Fish ◽  
The Difference

AbstractThe electric activity of mormyrid fish consists of short electric pulses, all identical, but separated by variable time intervals (inter-pulse interval or IPI). Temporal structures are here extracted from the sequence of IPIs, to show non-randomness in mormyrid electric signal. The electric activity of isolated Marcusenius macrolepidotus is comparable to that of other mormyrids. The pulse waveform is biphasic and symmetrical, it lasts 0.3 to 0.5 ms and its amplitude is about 13 volts. The pulses follow each other with extremely variable IPIs (14-500 ms) with large instantaneous variations. Two new methods of analysis have been developed here. The first is based on the fact that when IPIs are grouped in populations, longer IPI populations have a wider range than shorter ones, a lognormal rather than a normal distribution. The IPIs are therefore classified according not to absolute- but to relative differences: binwidths are in percent, not in milliseconds. The second, non-parametric method (sequential inequality testing), was first used for neurone firing activity. It considers the sign (+ or -) of the difference between successive IPIs, and compares the sequence of these signs with a theoretical random model. When M. macrolepidotus is resting, the sequence of longer and shorter IPIs is not random, as shown by redundancies of patterns of + and - signs. These redundancies and the IPI populations are typical for each individual. When the fish increases its locomotor activity (either spontaneously for a few seconds, or provoked over more than 20 s) the IPIs are shorter. The patterns of + and - are different when the fish is swimming and when resting. Behavioral and electrophysiological data suggest that receiving conspecifics may recognize these rhythm features. The analysis methods developed here may be useful to other stochastic phenomena, such as neural firing activity.

Low-cost biosensors for continuous performance assessment of natural-based wastewater treatment systems

2021 ◽  
Author(s):  
Marta Fernandez-Gatell ◽  
Xavier Sanchez-Vila ◽  
Jaume Puigagut
Keyword(s):  
Wastewater Treatment ◽  
Electric Current ◽  
Microbial Activity ◽  
Low Cost ◽  
Domestic Wastewater ◽  
Electric Signal ◽  
Bioelectrochemical Systems ◽  
Operational Conditions ◽  
Treatment Facilities ◽  
Wastewater Treatment Systems

<p>Bioelectrochemical systems (BES) are devices that transform the chemical energy of organic and inorganic substrates into an electric current. BES represents a particularly interesting biosensor technology for monitoring the performance of  remote/isolated wastewater treatment facilities (such as constructed wetlands). The work presented here aimed to assess the potential use of the electric signal produced by low-cost, membrane-less BES systems as an indicator of the operational conditions and treatment performance of natural-based wastewater treatment systems. For this purpose, several BES configurations and operation modes working under real domestic wastewater conditions were monitored.</p><p>Results showed that the electric current produced by the BES significantly correlates with key parameters in biological-based wastewater treatment systems such as microbial activity and biomass, water COD or solids accumulation. Therefore, our work demonstrates the feasibility of applying bioelectrochemical-based low-cost biosensors for the improvement and control of natural-based wastewater treatment systems.</p><p> </p><p> </p><p>Keywords: bioelectrochemical systems, wastewater, microbial activity, organic matter, low-cost, biosensor</p>

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