In order to prevent further spread of the novel coronavirus SARS-CoV-2, many states and countries are currently relying on exit restrictions, distance requirements and mouth and nose protection masks. But this is neither practicable nor sufficient in the long term. A few days ago, scientists from Switzerland presented a sensor that measures the concentration of the SARS-CoV-2 virus in the air and triggers an alarm if the concentration of this virus is too high. A good and important milestone in prevention.
A private initiative from Baden-Württemberg is now pursuing a different, much broader approach. It has set itself the goal of developing a kind of "early warning system" for excessive virus concentrations. What started just three weeks ago has already developed into a concept that the initiative has applied for a patent. What is behind it?
"As a team, we have developed the idea
...to build a sensor which, once completed, will be able to measure particles such as viruses and their concentration in the air in real time - including SARS-CoV-2," explains Prof. Dr. Ralph Wystup, one of the initiators of the project. The concrete development goal: a sensor system that provides early warning - even without knowing exactly where the actual "source of the fire" is.
"In the first step, you don't have to be able to determine...
...exactly which virus it is," explains Wystup. "First of all, it is sufficient to measure whether there is an increased viral load at all and if so, to issue a warning. You can think of it as a smoke detector. It doesn't matter whether the smoke comes from a pan on the stove or from a defective toaster. It does not report the cause, only the fact that smoke is present. The reason for the smoke can be investigated later. In the case of the smoke detector, this should of course be done immediately, and here the cause can certainly be found quickly. In the case of the viral load, this is already more complex. If you use a sensor that immediately carries out the analysis for a specific virus, you lose valuable time. In addition, most sensors only detect the precisely matched viruses. But viruses change. So if a slightly differently specified virus comes along, detection and analysis becomes more difficult. That's why it's so important not to waste unnecessary time analyzing the particles in question, but to warn immediately that something dangerous might be there.
The new system is...
...around a non-specific sensor - unlike the corona sensor from Switzerland. The measuring principle behind it is a purely physical one. Based on a light source, the sensor system records the physical and biochemical properties of particles in the air. It differentiates between organic and inorganic particles, measures their diameter and determines their concentration. "We scan the particle field in the air," says Wystup. "Because the sensor can differentiate between organic and inorganic particles and determines their concentration at an adjustable diameter, statistical analysis allows us to draw fairly clear conclusions about a specific virus. By wobbling the measuring frequency, a diameter distribution of the particles can also be determined. The use of AI, which is also possible, makes it possible to make the sensor network intelligent so that it searches for a specific particle size when other sensors in the network detect suspicious clusters in order to increase the accuracy of triggering, for example. Another advantage is that the system can be adjusted to new virus parameters, such as the diameter, via software updates. "This is important because viruses change," says Wystup. "Then it is important to quickly adapt the sensor system."
With the virus early warning system...
...the members of the German Initiative are going their own way. However, the example of the Baden-Württemberg and Swiss approaches shows that different concepts can fit together quite well: "The sensor developed by the Swiss colleagues would be an ideal complement to our early warning system," the expert explains. "Our permanently installed sensor system measures the particle concentration in the air, analyses the physical and biochemical properties and warns in case of danger, and the mobile virus sensor from Switzerland analyses whether, for example, SARS-CoV-2 is involved." The Swiss colleagues are also working on the development of a mobile virus sensor.