Learning Thru Research: What is the behavior of an organism when exposed to an electric field ?

February 5, 2017

What is the behavior of an organism when exposed to an electric field ?

For this second week of Biosensors we had to work about forces. Our group, Electro4worm, chose to work about the remarkable behaviours of Caenorhabditis elegans in presence of an electric field (want to see ? Click here !)

We compared their behaviours depending on the voltage, the frequency and the direction of the electric field induced by two electrodes connected to the power supply. Also, we tested the threshold of detection between the worms and the Movuino sensor.

Our protocol was based on previous studies 1, 2 : we needed a power supply able to generate an electric field up to 8 V/cm, chips with special channels designed, special agar and C. elegans. Chips were created on the basis of three shapes to test several parameters:

Fig 2: Each chip had a specific role. The first one is used to measure the speed of C. elegans in straight line. The second one to see if C. elegans follows electric field lines. The thirst one allows us to see if C. elegans could choose the right way oriented toward the electric field.

With this set-up we faced lots of problems: from the power supply that was not powerful enough, to the lack of tools to observe them and collect their movements, we decided to stop to study C.elegans. We had already changed 3 times our protocols when we realized that we better had to see if the organisms available in the laboratory would be sensitive to the electric field.

We did our experiment on Artemia salina, larvae of Chironomus plumosus, the bioluminescent algae Pyrocystis fusiformis and the carnivor plant Dionae muscipula.

With the power supply that we had, we're not really able to see a specific behaviour for this organisms, but we had lot of data with the larvae of Chironomus plumosus so we did our last experiment with them.

Results of this experiment:

For our last experiment, we placed approximately one hundred larvae in water, with two electrodes on the side of the plate and we filmed them to observe later their reaction to different voltage (V) and intensity (Hz).

Plate with the different part, and the electrode in red.

To analyze the video, we separate the plate in three section A, B, C

with the electrode in part B of the plate. We observe in function of the time the number of larvae in each part.

To analyze the results to our sensor, the magnetometer of movuino, we put the movuino in a plate with agar and we create an electric field that we vary, when we create an electric field, a magnetic field is created too, and it’s this field the movuino capt.

We can see on this curve a little increase enter 5 and 10V, but we think this increase is due to electric noises around the sensor than a real detection of an magnetic field.

Because to create a magnetic field we need to have a device powerful than the one we have.

In the end, we can't really conclude about how an organism react to different electric field, but we learned a lot about the laboratory, the different techniques with the microscope, how to create an electric field and more precisely in electricity and electronic in general.

We hope to continue to work on this subject later in our career, the impact of electricity and more precisely the electric and magnetic field in our fauna and flora is really important in our world which continue to use more electronic objects, in all the place without paying attention to the effects on organisms.