eDNA filtration capsules

In partnership with the Canadian company Waterra, specialised in groundwater monitoring and sampling equipment, Argaly is a European reseller of eDNA filtration capsules. Those capsules are effective at recovering DNA from aquatic organisms from filtrations of large volumes of running or stagnant waters.
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Technical caracteristics of the capsules

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The commercialised capsules contain 600 cm² of high quality polyethersulphone 0.45 micron filter media
allowing to capture DNA from aquatic organisms.
Those filters can be used in high turbidity waters and filtration volumes can go up to 100 liters.
Other pore sizes are available on demand: 0.1, 0.2, 0.45, 1 and 5 micron. 

The filtration pump

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The pump, CE certified, is connected to a battery that can hold a charge for up to 12 hours with only 4 hours of recharging.
The pump is equipped with a flowmeter at the pump outlet, allowing to monitor the filtered volume at any time.
The watertight case, attached by a shoulder strap, allows to perform the sampling with free hands and feet in the water, if necessary, without risk.
With filtration upstream of the pumping system, the risk of contamination is eliminated, allowing the same pipes to be used for multiple samples (and reduce waste).

The filtration technique

The filtration technique proposed by Argaly, with a pumping system downstream of the capsule, eliminates the need to change the pipes between samplings and limits the risk of contamination.
One end of the pipe is placed on the capsule outlet and the other end is connected to the peristaltic pump. A second pipe placed on the pump outlet  allows the filtered water to be evacuated. 
As an example, a filtration of 30 minutes in clear water allows to collect around 40 liters of water (depending on the pump used).
Once filtration is complete, the capsule is emptied and then filled with DNA preservation buffer. Airtight caps are used to seal the capsule. After shaking the capsule, the preservation buffer will either be collected in a Falcon tube or stored in the capsule at room temperature until it is sent to the laboratory.
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The shaker

To optimize DNA collection, we recommend shaking the capsule vigorously directly in the field after pouring the preservation buffer in the capsule.

Tests have shown that DNA is more easily retrieved when it is immediately resuspended compared to when it remains on the membrane for a few days/weeks before DNA extraction in the laboratory.

For this reason, our supplier Waterra has developed an easy to use shaker, adapted to its capsules, to optimise the amount of DNA collected during  aquatic sampling.

References

These filtration capsules have been compared with other methods for detecting aquatic species and their effectiveness has been demonstrated (see the scientific article on this subject: Peixoto et al. 2020).
Researchers from the Laboratory of Alpine Ecology of Grenoble (Dr Pierre Taberlet and Dr Fredreric Boyer) have also validated the use of those capsules in their eDNA research project on lagoon environments. 
To know more about the capsules, don't hesitate to contact us!