A biochip for recording electrophysiological signals of nematodes

1. A biochip for recording electrophysiological signals of nematodes Group 13-27 Advisor: Liang Dong Group members: XuanQiao Yuncong Chen Yang Cui Ruiyu Chen

2. Introduction • Overview • Project design • Related background • Project working process

3. Overview of our project General view Detail structure Testing environment Amplifier circuit

4. Concept sketch • Biochip device: container as an environment • Electrodes: electrophysiological signal transform • Amplifier: electrophysiological signal measurement

5. Testing Target C. Elegans

6. Our Design High efficient trapping Convenient electrodes

7. Our Design 30 um gold electrodes 15 um channels

8. Why C. elegans • The genes of C. elegans nematodes are similar to those of human beings. • Nematodes are simple, easy to study • Biologists use C. elegans as model system to study toxicology and discover new drugs for human metabolic and degenerative diseases

9. Why Electrophysiological signals • Electrophysiological signals from C. elegans provide information about the activity of the pharynx (throat) which pumps like a heart during feeding • C. elegans has a distinct set of drug receptors present on its pharynx.

10. Why biochip • Low cost - $30/liter can make a hundred of our devices • High throughput - Once you have the design, it is easy to make hundreds of biochip devices • Simple operation - Biochip devices are easy to use

11. Schametic Amplifier Design

12. Simulation Result:

13. Testing inveriment We don’t have the optical table to eliminate the influence from movement of people 2. When we do the test in Coover, there is no wire box to enclose the testing area to filter the noise in the air

14. Testing result Initial Contraction Terminal Contraction The amplitude shows how strong the nematode is pumping. The frequency shows how frequent the nematode is pumping.

15. Working process Spin the Biochip Pick worm By using the spinning coder, the biochip can get the worms in every channels. This is why we call it “high trapping rate” Worms in the bio chip

16. Working process Channel Pharynx Electrode Nematode

17. Working process

18. Challenges in The Project • 15 um channel fabrication • Gold etching process • No alignment mark • Noise reduction

19. Questions

20. Back up slides

22. Constraints & Considerations All equipment and device need to set up on a experiment table. Group members should wear lab cloth, gloves and goggles. Gold etching with strong acid

23. Our project

24. Non-functional requirements device fabrication • Taking Picture of Worms and Taking video Electrodes fabrication • Do alignment with microscope

25. Division of Labor • Xuan& Yuncong & Yang: device design, fabrication and Electrodes fabrication • Abhishek & Ruiyu: amplifier design and construction

26. Potential Risks • Alignment for device and electrodes • Chemicals, sharps, UV exposure, worms • Burning of op-amps, resistors, capacitors • Noisy signal • Strong acid in electrodes fabrication • Worms die in culture

27. Mitigation • Being generally diligent will go a long way • Ductility: most experienced member will make device to ensure proper thickness • Safety risks: all trained in lab safety, know proper procedures to avoid accidents • Burned components/noisy signal: use of quality components and careful construction

28. Market Survey traditional experiment: 1. trap and test worms one by one 2. Expensive and waste time Our design: 1. trap and test 16 worms at the same time 2. The device is small and cheap