Microplastics pose a significant environmental threat and are present nearly everywhere on our planet. These tiny particles result from the breakdown of materials like tires, clothing, and plastic packaging, as well as from microbeads found in numerous cleansers, cosmetics, and personal care items.
In a groundbreaking initiative to tackle this issue at its source, researchers at MIT have engineered a new class of biodegradable materials designed to replace the conventional plastic beads used in beauty products. These innovative polymers degrade into harmless sugars and amino acids.
“To combat the microplastics crisis, we must not only address existing pollution but also focus on developing materials that won’t create microplastics in the future,” explains Ana Jaklenec, a principal investigator at MIT’s Koch Institute for Integrative Cancer Research.
Beyond their potential in cosmetics, these particles may have broader applications. The study conducted by Jaklenec and her team demonstrates that the biodegradable particles can encapsulate essential nutrients like vitamin A. This approach could benefit the roughly 2 billion people globally who suffer from nutrient deficiencies.
The senior authors of this study, Jaklenec and Robert Langer—an MIT Institute Professor—have collaborated on this research, which was published in Nature Chemical Engineering. The paper’s lead author is Linzixuan (Rhoda) Zhang, a graduate student in chemical engineering at MIT.
Biodegradable Plastics: A Sustainable Solution
In a previous study from 2019, Jaklenec, Langer, and other researchers introduced a polymer capable of encapsulating vital nutrients like vitamin A. They noted that individuals who consumed bread fortified with encapsulated iron exhibited increased iron levels. However, the European Union subsequently classified this polymer, known as BMC, as a microplastic, leading to a ban implemented in 2023. Consequently, the Bill and Melinda Gates Foundation, which funded the original research, requested MIT’s team to search for a more environmentally sustainable alternative.
Under Zhang’s leadership, the research group explored poly(beta-amino esters), a type of biodegradable polymer previously developed by Langer’s lab. These polymers, recognized for their potential in gene therapy and various medical applications, can be designed to break down into benign components like sugars and amino acids.
By altering the composition of these polymers, the team adjusted properties like hydrophobicity (water repellency), mechanical strength, and pH sensitivity. After synthesizing five distinct materials, the MIT team identified one with ideal characteristics for microplastic applications, including disintegration in acidic conditions such as those found in the stomach.
The researchers successfully demonstrated that these particles could encapsulate not just vitamin A, but also vitamin D, vitamin E, vitamin C, zinc, and iron. Many of these nutrients are prone to degradation due to heat and light, yet the researchers found that when encapsulated, they remained stable even after exposure to boiling water for two hours.
Additionally, after six months of storage in high-temperature and humidity conditions, over half of the encapsulated vitamins remained intact.
To illustrate their potential for food fortification, the researchers incorporated the biodegradable particles into bouillon cubes, a staple consumed in many African nations. They discovered that the nutrients maintained their integrity after boiling for two hours.
“Bouillon is an essential ingredient in sub-Saharan Africa and presents a tremendous opportunity to improve the nutrition of billions in these regions,” states Jaklenec.
Safety was a crucial consideration, and the team tested the particles on cultured human intestinal cells, finding no adverse effects at the concentrations typical for food fortification.
Innovative Cleansing Solutions
To evaluate the capacity of these particles to replace microbeads commonly added to cleansers, the researchers combined them with soap foam, discovering that this mix effectively removed permanent markers and waterproof eyeliner from skin surfaces, outperforming soap alone.
When compared to cleansers containing polyethylene microbeads, their biodegradable alternative proved to be more efficient. The research also revealed that the new particles excelled at absorbing potentially harmful elements, such as heavy metals.
“This project serves as a crucial first step, demonstrating the ability to develop a new class of materials that can expand their applications and mitigate the environmental impact,” remarks Zhang.
Supported by a grant from Estée Lauder, the research team intends to conduct further testing on the microbeads in cleansing products and may initiate a small human trial later this year. They are also compiling safety data to apply for GRAS (generally recognized as safe) status from the U.S. Food and Drug Administration and consider a clinical trial for foods fortified with these biodegradable particles.
Through these efforts, the researchers aspire to significantly lessen the release of microplastics from health and beauty products.
“This is just one segment of the broader microplastics issue, but society is increasingly acknowledging the gravity of the problem. Our research represents a progressive step toward resolution,” adds Jaklenec. “Polymers offer indispensable benefits in numerous daily applications, yet they also have drawbacks. This illustrates how we can alleviate some of those negative impacts.”
This research was funded by the Gates Foundation and the U.S. National Science Foundation.
Photo credit & article inspired by: Massachusetts Institute of Technology
