July 20, 2017
NUST MISIS scientists have developed a universal protective filter against ultraviolet radiation by modifying zinc oxide nanoparticles. The filter is especially versatile, capableof being used both in the polymer industry and cosmetology.
Most people have experienced sunburn in their life, something caused by ultraviolet radiation whose intensity exceeds the skin’s natural protective ability to tan. The most dangerous part of sunburns, considering the degree of impact, is considered to be UV radiation of type B, which ranges from 305 to 320 nanometers. In large quantities UV radiation can also lead to mutations that cause melanoma (skin cancer) and the premature aging of skin cells. Additionally, ultraviolet radiation can damage many different polymers (plexiglass, polyethylene, polypropylene, etc.), a phenomenon known as ultraviolet ageing.
Various filters and additives to polymer compositions and suntan creams are widely used in the world to protect against radiation’s harmful and damaging effects. Filters are usually metal oxide based, such as titanium dioxide or zinc oxide. But some sources have reported that titanium dioxide nanoparticles may cause cancer, while zinc oxide is inconvenient in that it is white in color (it is the main component of ZnO-based white paint).
“To achieve a universal UV safety filter, NUST MISIS researchers, in cooperation with the Blokhin Russian Oncological Scientific Center, came up with a new approach based on the chemical synthesis of zinc nanoparticles with a modified surface”, said Alevtina Chernikova, Rector of NUST MISIS.
Scientists learned how to control the optical properties of zinc oxide nanoparticle-based UV filters directly in the process of their chemical synthesis. During experiments, a solution of nanoparticles and polypropylene film with a nanostructured additive demonstrated 100% absorption of Type B ultraviolet.
“We have synthesized zinc oxide nanoparticles with a modified surface. The study of how a modified surface impacts the chemical and physical properties of zinc oxide nanoparticles has shown that the resultant nanoparticles can be used as safety filters against UV radiation. Our in vitro experiments have demonstrated the lack of hematoxicity in synthesized nanoparticles with a surface modified by silane-containing compounds as they were incubated with donor blood”, said Svetlana Senatova, research fellow at NUST MISIS, Candidate of Chemical Sciences.
Since the small size of nanoparticles allows them to permeate through skin layers and enterthe human body, scientists need to understand how they will affect blood cells in a healthy body.
According to the researchers, modifying the surface of zinc oxide particles leads to greater transparency in the visible part of the spectrum, something that makes it possible to include them in the composition of both sunblock creams and transparent polymers. These materials can be used to manufacture transparent food containers, film, or face panels for open-air structures. Moreover, a modified surface of nanoparticles can reduce the amount of added UV filtration by 5–10 times,which is a much more cost effective approach.