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.
10 Breakthrough Technologies 2024
Every year, we look for promising technologies poised to have a real impact on the world. Here are the advances that we think matter most right now.
Scientists are finding signals of long covid in blood. They could lead to new treatments.
Faults in a certain part of the immune system might be at the root of some long covid cases, new research suggests.
AI for everything: 10 Breakthrough Technologies 2024
Generative AI tools like ChatGPT reached mass adoption in record time, and reset the course of an entire industry.
OpenAI teases an amazing new generative video model called Sora
The firm is sharing Sora with a small group of safety testers but the rest of us will have to wait to learn more.
Get the latest updates from
MIT Technology Review
Discover special offers, top stories, upcoming events, and more.