Not only asbestos but also other artificially-made fibres, such as building insulation. Doctors have known for a long time that their inhalation is harmful. Researchers from the Department of Thermodynamics and Environmental Engineering at the Faculty of Mechanical Engineering at BUT are now examining exactly how fibres behave when inhaled and how and where they settle in the lungs. They use their own unique lung model, one of the most advanced in the world, used by a number of scientific teams from around the world for testing and experiments.

Thermal insulation, such as mineral or glass wool, is known not only to builders but also to do-it-yourself men. But what happens in the lungs of a person who works with the material and is thus exposed to its inhalation? Researchers from the Brno Faculty of Mechanical Engineering are looking for the answer.

“We know a lot about how and why asbestos is harmful. But we know very little about how deeply it gets into the lungs. At the same time, inhaled fibres pose a much greater risk to the human body than spherical particles, because they can withstand the natural self-cleaning mechanisms of the lungs and cause serious health consequences," František Lízal from the Department of Thermomechanics and Environmental Engineering explained.

Researchers considered research with a variety of fibres, eventually opting for glass fibres of the blown-in insulation. "Calculating the behaviour of a spherical particle is easier and more accurate. On the contrary, when it comes to calculating the behaviour of fibre, it is very complicated. The fibre can rotate, which changes the pressure resistance and therefore the calculation of its movement is several times more difficult. We are trying to refine the prediction of where the fibre will get and where it will settle in the lungs," Lízal said.

Scientists test computational models on their own functional lung model, which is the most mechanically perfect in the world. It was introduced to the public four years ago, and since then scientists have improved it, for example, by adding an artificial nasal cavity. Now they can test the breath through the nose. "It is generally known that it is better to breathe through your nose if you want to protect yourself from harmful substances. In the nose, some of the particles separate and we were interested in where the rest, which passes to the lungs, settles and whether the places of the impact of the fibres are different from the situation when you would breathe through your mouth,“ Lízal added.

The experiments are performed by scientists with fibres with a diameter of 5-6 micrometres, which is about ten times less than a human hair. The length of the fibres may vary in practice, but to simplify the calculation, the researchers use a borrowed fibre length classifier. The device was borrowed from colleagues from the United States and is the only one of its kind that is currently in operation in the world. The researchers then let the fibres of the selected length into the lung model during a simulated breath and observe how they behave and where they are going. The speed camera and special software from the colleagues from the Department of Mathematics help them in the analysis. The colleagues from the Faculty of Chemistry help with the chemical analysis.

Research into fibre inhalation has potential for the use in medicine, for example, where it could help to link knowledge about certain diseases to where the particles settle. A typical example is some types of lung cancer, which typically occur in the upper lobes.

"Personally, I see great potential for its use in the pharmacy. The knowledge of particle flow and deposition can help select a better carrier for a drug substance within a so-called targeted drug delivery. At the same time, the data from the breathing of healthy people are used today for the development of inhalers, which does not make complete sense. On the contrary, we need to know what ill people breathing looks like in order for their treatment to be more effective. Therefore, our model can simulate, for example, asthma breathing. But then the imaginary relay pin is taken over by doctors and pharmaceutical companies, we can provide data that can be used as a basis," Lízal concluded.