A new microbead proves effective as a plastic-free skin cleanser

A new degradable microbead could soon replace plastic exfoliants in skin cleansers.

Polymer spheres effectively remove permanent marker and eyeliner on animal skin samples and break down into molecules similar to sugars and amino acids, researchers report Dec. 6 in Chemical Engineering of Nature. The beads offer a more environmentally friendly alternative to microplastic beads, scientists say.

In 2015, the United States banned companies from adding plastic microbeads to personal care products that are flushed down the drain to prevent them from entering waterways where marine life can ingest them. Some countries have implemented similar bans, but others still allow companies to add plastic microbeads as cleansers and exfoliants.

The new polymer could “really help move the field and get people thinking about different ways we can make materials that don’t even have the ability to be microplastics,” says Ana Jaklenec, an engineer biomedical at MIT.

Jaklenec and colleagues made the spheres, which average 76 micrometers, from a type of polymer known as poly(β-amino ester). Similar poly(β-amino esters) have been used for biomedical applications such as drug delivery throughout the body. The team tested how the spheres degraded in boiling water; after two hours more than 94 percent of the polymer had broken down into molecules linked to sugars and amino acids.

The researchers then mixed the microparticles with soap suds and used the mixture to remove the permanent marker from pig skin samples. Wiping the marks 50 times with the mixture removed about 74 percent of the ink, while wiping the marks with soap suds alone removed about 38 percent of the ink. The cleaning mixture removed eyeliner even more effectively: Ten wipes with the mixture removed almost twice as much eyeliner as the soap suds alone.

The polymer microbeads also absorbed copper ions from water, suggesting that unlike ordinary plastic microbeads, they could cleanse the skin of metals found in some types of dust (SN: 26.9.24).

That performance boost could prompt more companies to adopt more sustainable materials in the future, says Ben Elling, a polymer chemist at Wesleyan University in Middletown, Conn., who was not involved in the study.

“A lot of the fear of looking for more renewable or more degradable materials is that they often have worse properties than what you’re replacing,” says Elling. It’s easy to assume that there will always be a trade-off between performance and durability, he says, “but you can absolutely have the best of both worlds.”