scholarly journals Microfluidic devices for behavioral screening of multiple Zebrafish Larvae: Design investigation process

2021 ◽  
pp. 2100076
Author(s):  
Arezoo Khalili ◽  
Ellen Wijngaarden ◽  
Khaled Youssef ◽  
Georg R. Zoidl ◽  
Pouya Rezai
Author(s):  
Arezoo Khalili ◽  
Ellen van Wijngaarden ◽  
khaled Youssef ◽  
Georg Zoidl ◽  
Pouya Rezai

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.


2020 ◽  
Vol 12 (8) ◽  
pp. 211-220
Author(s):  
Arezoo Khalili ◽  
Ellen van Wijngaarden ◽  
Georg R Zoidl ◽  
Pouya Rezai

Abstract Multi-phenotypic screening of zebrafish larvae, such as monitoring the heart and tail activities, is important in biological assays. Microfluidic devices have been developed for zebrafish phenotypic assays, but simultaneous lateral–dorsal screening of the same larva in a single chip is yet to be achieved. We present a multi-phenotypic microfluidic device for monitoring of tail movement and heart rate (HR) of 5–7-day postfertilization zebrafish larvae. Tail movements were stimulated using electric current and quantified in terms of response duration (RD) and tail beat frequency (TBF). The positioning of a right-angle prism provided a lateral view of the larvae and enabled HR monitoring. Investigations were performed on zebrafish larvae exposed to 3% ethanol, 250 μM 6-hydroxydopamine (6-OHDA) or 1 mM levodopa. Larvae exposed to ethanol showed a significant drop in HR, whereas electric stimulation increased the HR temporarily. Larvae experienced a significant drop in RD, TBF and HR when exposed to 6-OHDA. HR was not affected by levodopa post-treatment, whereas RD and TBF were restored to normal levels. The results showed potential for applications that involve monitoring of cardiac and behavioral parameters in zebrafish larvae. Tests can be done using the same chip, without changing the larvae’s orientation. This eliminates undue stress caused by reorientation, which may affect their behavior, and the use of separate devices to obtain dorsal and lateral views. The device can be implemented to improve multi-phenotypic and quantitative screening of zebrafish larvae in response to chemical and physical stimuli in different zebrafish disease models.


2016 ◽  
Vol 136 (6) ◽  
pp. 244-249
Author(s):  
Takahiro Watanabe ◽  
Fumihiro Sassa ◽  
Yoshitaka Yoshizumi ◽  
Hiroaki Suzuki

Author(s):  
Matthew N.O. Sadiku ◽  
Adebowale E. Shadare ◽  
Sarhan M. Musa

Digital chain of custody is the record of preservation of digital evidence from collection to presentation in the court of law. This is an essential part of digital investigation process.  Its key objective is to ensure that the digital evidence presented to the court remains as originally collected, without tampering. The chain of custody is important for admissible evidence in court. Without a chain of custody, the opposing attorney can challenge or dismiss the evidence presented. The aim of this paper is to provide a brief introduction to the concept of digital chain custody.


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