On Nov. 12, 2025, a team of University of California, Berkeley-led researchers reported in Nano Letters that they have genetically engineered a harmless virus to act like a “smart sponge” that grabs rare earth metals from water, and, with a gentle change in temperature and acidity (pH), releases them for collection. Their unusual, groundbreaking approach could lead to a “clean” biological alternative to traditional extraction methods for REEs and other critical elements.

Today’s high-tech electronics and green energy technologies would not function without rare earth elements (REEs). These 17 metals possess unique properties essential to creating items like the phosphors that illuminate our mobile phone displays and the powerful magnets used in electric vehicles and wind turbines. But extracting these substances from raw materials is a dirty process that relies on toxic chemicals and leaves behind polluted waste.

“This is a significant move toward more sustainable mining and resource recovery,” said principal investigator Seung-Wuk Lee, professor of bioengineering at UC Berkeley and faculty scientist at Lawrence Berkeley National Laboratory. “Our biological solution offers a greener, low-cost and recyclable way to secure the critical materials we need for a clean energy future while helping to protect the environment.”

The key to their approach was transforming the bacteriophage — a virus that infects only bacteria and is harmless to humans and the environment — into a “highly selective recycling machine.” The researchers achieved this by adding two specialized proteins to the virus’s surface. One protein, lanthanide-binding peptide, acts like a molecular claw, tuned to grab REEs. The other, an elastin motif peptide, acts as a simple, non-toxic, temperature-sensitive switch: when the virus is gently warmed, it drops out of the solution, along with the REEs.

In addition to extracting REEs from mining wastewater, the researchers envision this platform being used for other critical applications, including harvesting REEs from e-waste, such as old phones or laptops, and for environmental remediation.

The researchers also discovered that the viruses didn’t lose their effectiveness after completing the job, making them reusable. In addition, researchers can easily and cheaply grow vast quantities of the virus simply by infecting bacteria with them, as they will then self-replicate.

This work was supported by the National Science Foundation and the U.S. Department of Energy.