What is "microbead"

n. A microscopic bead

Microbeads are manufactured solid plastic particles of less than five millimeters in their largest dimension. They are most frequently made of polyethylene but can be of other petrochemical plastics such as polypropylene and polystyrene. They have been used in exfoliating personal care products and toothpastes, as well as in biomedical and health science research.

Microbeads can cause plastic particle water pollution and pose an environmental hazard for aquatic animals in freshwater and ocean water. In the US, the Microbead-Free Waters Act of 2015 phases out microbeads in rinse off cosmetics by July 2017.

Microbeads are uniform polymer particles, typically 0.5 to 500 micrometres in diameter. Bio-reactive molecules can be absorbed or coupled to their surface, and used to separate biological materials such as cells, proteins, or nucleic acids.

Microbeads have been used for isolation and handling of specific material or molecules, as well as for analyzing sensitive molecules, or those that are in low abundance, e.g. in miniaturized and automated settings.