Small synthetic particles added to cosmetic products as exfoliants account for almost 2% of the annual microplastics released into the oceans. A group of researchers from the Massachusetts Institute of Technology (MIT) have developed a new biodegradable component with the potential to end this problem.
The proposed material is derived from work done in 2019 by a team led by Linzixuan Zhang, a graduate student in chemical engineering at MIT. The study resulted in the creation of a set of microbeads known as BMCs. Manufactured based on the union of the monomers butylmethacrylate, 2-dimethylaminoethylmethacrylate and methylmethacrylate, the particles proved to be useful for encapsulating vitamin A and other essential nutrients. Despite this, they are not degradable. This has limited its practical application. The European Union has classified them as a polluting and harmful agent, and It has banned its use since 2023.
The new research published in the magazine Nature Chemical Engineering and directed by Robert Langer, a professor at MIT, took up these findings to generate a more environmentally friendly proposal. The project manager had in the past created a type of laboratory polymer known as poly(beta-amino esters). These polymers, also known as PAE and based on natural primary materials, degrade by hydrolysis into low molecular weight products such as sugars and amino acids.
Langer and colleagues synthesized PAEs with three bifunctional monomers: piperazine, 4,4′-trimethylenedipiperidine (TDP), and isosorbide. By adjusting the ratio of the three substances, they produced five polymer compositions. Options were evaluated for use in microbead production. The scientists discovered that those with higher amounts of TDP adopted a spherical morphology and smooth surface, which made them ideal for application in personal care products. Furthermore, they observed acceptable degradation in hot water and bacterial conditions. After the boiling process, only 5.5% of the polymer survived.
Beyond cosmetics
Specialists explored the potential of PAE particles as cleansing ingredients in beauty products. They combined the compounds with soap suds and discovered that the mixture was able to remove traces of permanent markers or eyeliners with complete effectiveness. They also found that they can replace the function of polyethylene microspheres and absorb potentially toxic elements, such as heavy metals.
Ana Jaklenec, principal investigator at MIT’s Koch Institute, asserts that “one way to mitigate the problem of microplastics is to figure out how to clean up existing contamination. But it is equally important to look to the future and focus on creating materials that don’t create this type of pollution in the first place“.
The experts also examined the properties of their invention to contain substances such as zinc, iron and vitamins A, D, E and C. They explain that “many of these nutrients are susceptible to degradation by heat and light, but when condensed by These particles can withstand exposure to boiling water for two hours.” They add that more than 50% of the vitamins retained their properties after being stored for six months in conditions of humidity and high temperatures. When exposing the compound to human intestinal cells, no adverse effects were observed.
Jaklenec says, “This is just a small part of the broader microplastic problem, but as a society we are starting to recognize the seriousness of the problem. “This work represents a step forward to address the issue.”
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