Skip to Content

Monitoring heavy metal contaminants-such as lead, mercury and cadmium-in rivers and wells requires multiple trips to the lab for analysis with expensive and bulky equipment. A team of chemists headed by Joseph T. Hupp at Northwestern University has a more efficient method that could be adapted to make a portable device for testing samples in the field. Hupp’s group starts with nanoscale-sized particles of gold, each smaller than a virus. They then coat the particles with molecules that are able to bind with the heavy metals. Water containing the particles naturally assumes a deep shade of red. But if, for example, lead ions are present, they attach to the receptors, causing the gold particles to aggregate and turn the water blue. The greater the lead concentration, the more dramatic the color change. Then, to determine the exact quantity of heavy metal in the water, the Northwestern researchers measure its absorption of ultraviolet light. While not as sensitive as standard tests, the nano method’s speed and low cost make it an attractive alternative.

Deep Dive

Uncategorized

Embracing CX in the metaverse

More than just meeting customers where they are, the metaverse offers opportunities to transform customer experience.

Identity protection is key to metaverse innovation

As immersive experiences in the metaverse become more sophisticated, so does the threat landscape.

The modern enterprise imaging and data value chain

For both patients and providers, intelligent, interoperable, and open workflow solutions will make all the difference.

Scientists have created synthetic mouse embryos with developed brains

The stem-cell-derived embryos could shed new light on the earliest stages of human pregnancy.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.