Researchers at St. Petersburg State University in Russia have learned to “tune” nanoparticles so that they themselves gather in the desired structure and form the pores of new membrane materials. This development can make production more environmentally friendly and greatly simplify the cleaning of substances that are self-shelf proteins or blood components.
Scientists at St. Petersburg State University proposed to replace non-ecological additives with hydroxyapatite, a substance that makes up human teeth and bones. It is safe for the environment and is inherently harmless to living organisms. But to implement this idea, it is necessary to create conditions for the nanopowder of hydroxyapatite to form the pores of the desired size.
It turns out that small particles of hydroxyapatite can be forced to fuse each other – as the details of the design, but it happens chaotically. Scientists at St. Petersburg State University have developed a method that allows them to control this process, causing particles to connect as necessary. In the solution, ions are added, for example, potassium or ammonium, which cover some facets of nanoparticles and do not allow them to connect. As a result, the particles are built in the desired way and the desired length and thickness are obtained.
As explained by the student-chemist of the first year of the master’s degree of St. Petersburg State University Ksenia Meshina, the researchers thus mixed the materials with a polymer and made of this mass a film a thickness of only 50-100 micrometers – thinner than human hair. These new partitions were checked when cleaning the solution of bullish sewing albumin – a model protein that is often used in laboratories to mimic the treatment of whey or drugs.
The samples were retained by more than 99.9% of the protein, while passing the liquid five times faster than the films obtained with the addition of industrial breeders instead of hydroxyapatite. It was possible to get such a result due to the features of the material: protein molecules are not just stuck in holes, but also stick to hydroxyapatite nanoparticles. This temporary binding helps to keep a valuable product by reducing losses during filtration.
“Usually, scientists and engineers are struggling with clogging such structures. We decided to use this feature for our own good. In medicine or in the production of baby food, protein loss can lead to serious economic costs. Our films work as a smart sieve that not only misses unnecessary ones, but also effectively delays useful molecules. Moreover, stuck protein molecules can then be collected by cleaning the filter, and used, for example, for analysis, ”said Olga Osmolovskaya, a project manager at SPbSU.
At the same time, the technology does not require complex equipment and is ready for scaling.
