Antifungal nanofibers from plastic waste
Plastic bottles as raw materials for antifungal medicine
Alexander Berezin, Compulenta2.5 million tons of plastic bottles based on polyethylene terephthalate (PET) are sent to waste annually.
The intensity of passions around this is such that in several countries these products are simply banned; all others taste the charms of the growing Everest of extremely slowly degrading garbage...
...Meanwhile, PET can serve as a source material for the creation of innovative medicines!
Researchers from IBM and the Institute of Bioengineering and Technology (Singapore), led by Yi Yan Yang, are working on a way to eliminate PET waste that would not only not pollute the environment, but would also yield a valuable product.
Although Candida albicans is present in almost all adults, in a weakened body (often already seriously ill) it can become a real scourge. And the fight against this and other fungi by traditional means can be protracted and not very effective. (Photo by Muhsin Ozel, Gudrun Holland / RKI.)
In search of such a solution, scientists have created a special type of self-assembling nanofiber based on polyethylene terephthalate. The final polymer in such fibers has a significant positive charge. Why is this necessary?
The fact is that fungal diseases, they are also mycoses, which torment a billion people all over the planet every year, are difficult to defeat, not least because the medicine, on the one hand, must penetrate the cell wall of fungi, and on the other hand, be very selective and distinguish a fungal cell from a human one. And if a drug satisfies one requirement, it usually has problems with another, especially since the metabolisms of mammalian and fungal cells do not differ so much.
Well, the new nanofiber is relatively easy to target the fungus. The surface of fungal cells has a negative charge, which differs from ordinary human cells, and the nanofiber is attracted to them, creating an increased concentration of positive ions near the focus of mycosis. Over time, the latter penetrate the cell wall and destroy the target cell, guaranteed to exclude the occurrence of adaptation to such a method of struggle.
"The ability of such molecules to self-assemble into nanofibers is very important because, unlike conventional molecules, these structures create an environment with a high content of positive ions... This radically facilitates the choice of a target and its subsequent destruction through the destruction of cell walls," emphasizes Yi Yan Yang. "And this means that fungal cells can be destroyed even with a small concentration of such nanofibers."
And indeed, in experiments, the new drug destroyed 99.9% of Candida albicans cells, known to you as the causative agent of thrush, which in the same USA is the third most common type of bloodstream infections. By the way, the exposure time is only an hour, and even after growing single surviving cells and re-processing them (11 cycles in total), they did not show the slightest traces of resistance development. On the contrary, conventional antifungal drugs could only suppress further reproduction of the fungus, and after six cycles of selection of surviving cells, resistance began to appear among them, which is fraught with the rapid emergence of lines completely immune to such drugs.
Further tests that dealt with other types of mycoses showed the universality of the mechanism of destruction of their cells by nanofibers, and this is evidence of the creation of a new antifungal drug with a broad spectrum of action and safe for the human body. The latter is especially important because mycoses most often affect people with immunodeficiency, HIV patients, patients after chemotherapy or organ transplantation, when weakened immunity and the body are sensitive to even small side effects.
Moreover, even biofilms of fungal origin are easily destroyed by the new nanofiber, and after one treatment, while conventional antifungal drugs are in principle ineffective against biofilms, where target cells are protected by additional layers.
To test the capabilities of the new drug on a real disease of the same C. albicans, a mouse eye was infected. After applying the healing nanofiber, the growth of fungal structures in the cornea stopped, and the inflammation abruptly subsided. Subsequent analysis of animal cells showed that the new drug does not pose any threat to them, because there are not even traces of erosion on the surface of the eye caused by the application of nanofibers.
Prepared based on IBM materials: IBM Research and Institute of Bioengineering and Nanotechnology Convert Recycled Plastics into Disease Fighting Nanofibers
Article by Fukushima et al. Supramolecular high-aspect ratio assemblies with strong antifungal activity is published in the journal Nature Communications – VM.
Portal "Eternal youth" http://vechnayamolodost.ru11.12.2013