In March this year, a consortium of various research institutions started the development of a biosensor for real-time virus detection in water. It would be a world first. According to André van der Wurff of Groen Agro Control, there is a great need for a sensor that can detect plant-pathogenic viruses in water systems in real-time.
"The sensor must be able to distinguish between infectious, 'live' material and non-infectious, 'dead' material," he adds. "That is not easy, as the first results confirm."
At Glastuinbouw Waterproof, André gives an update on the joint project of KWR Water Research Institute, Control Food & Flowers Foundation (SCFF) and TNO, with the cooperation of Glastuinbouw Nederland, Groen Agro Control and Sendot Research. The financiers are Stichting Kennis In Je Kas (KIJK), Plantum, Stimuflori, Stowa, Topsector Tuinbouw & Uitgangsmaterialen and Topsector Water.
Distinction between living and dead
"A tricky point in virus detection is the distinction between non-infectious, 'dead' material and infectious, 'living' material," explains the microbiological researcher. "Only infectious material can multiply in a host and is therefore important. TNO's detector is able to measure both the amount of virus - in other words, the number of bonds that are formed - and the binding strength between virus and antibody. A strong bond corresponds to a 'live' virus, a weak bond to a 'dead' virus. We want to translate this principle into a practical and affordable optical sensor for plant viruses. It would have to be coated with antibodies that bind these viruses."
Results and no results
In a series of tests, water containing the model virus MS2 was treated with chlorine and/or UV light in order to partly inactivate the virus. These samples were then tested at TNO.
"This control exercise worked perfectly," says Van der Wurff. "Now we could really get going, or so we thought. We made a few series with water samples that contained cucumber fur virus and PlamV. These were also run through the Biacore. To our surprise, nothing at all was measured."
That was a setback, but it is not yet clear whether the road has come to a dead end. According to the various experts, there could be various reasons for the setback. One possibility is an unwanted interaction with the plant material used to contaminate the water with cucumber fur virus and PlamV. Such contaminants were absent in the test with MS2.
Another possibility is that the antibodies used do not react with KKB and PlamV. As a result, no binding occurs.
"We want to use a simple test to determine initially whether plant residues cause any disruption," continues Van der Wurff. "This can be done by adding virus-free plant material to water with MS2 and then run it through the Biacore. If it does not measure anything, then contamination by plant material is indeed the culprit. If it does measure something, we need to zoom in on the interaction between the plant viruses in question and various antibodies. We will soon hear whether we can move on. We hope we can, because good and consistent measuring results are essential before we can start translating them into handy biosensors. We will undoubtedly encounter the necessary hurdles with that, too."
Source: Glastuinbouw Waterproof