American scientists have tested more than 70 different combinations of fabrics and materials on the permeability to virus-like particles. They found that the Terry cloth, quilted cotton or flannel, in combination with polypropylene, polyester or polyaramid protect against nanoparticle size from 10 to 200 nanometers is not worse medical respirators N95 (FFP2 roughly corresponds to). The results of a study published in the journal ACS Nano.
Pandemic COVID-19 has caused an increased demand for personal protective equipment, including medical mask. Previously, researchers have measured the effectiveness of masks as protection from dust, viruses and bacteria, and then it turned out that conventional medical masks can help stop the spread of seasonal coronavirus, a relative of SARS-CoV-2. But due to the lack of PPE people often have to make masks out of scrap materials, and you need to know what fabrics and materials are best suited.
The American scientists under the leadership of Stephen Lustig (Steven R. Lustig) from northeastern University decided to find out how the material and number of layers of the mask affects the efficiency of latency of viral particles. Scientists chose more than 70 different material combinations and tested them on a homemade setup, which simulates the pressure and speed of air flow created by a human during respiration. The device also spray in the air flow fluorescent aerosol particles that mimic the virus particles. The shell of these particles the researchers created from a copolymer of lactic and glycolic acids, and inside put the fluorescent dye rhodamine-6G. This compound has a high quantum yield, and thus it can be seen easily using, for example, scanning electron microscopy.
The role of the lungs in experimental setup complied with the compressor, which blows air into the camera with a spray of aerosol. Then the flow of air with nanoparticles was done through a narrow channel into a wide chamber, whereby the aerosol is uniformly distributed in the system. Wide camera gradually narrows and becomes a narrow nozzle at the end of which is the tested material. For a sample of material is a glass plate, which collects the aerosol particles that have passed through the material. After each test, the scientists looked through the glass plate with an electron microscope and measured the quantity of nanoparticles deposited on the glass plate.