Developments to Watch

TRACKING TOXINS WITH MOLECULAR `BUCKETS'

Monitoring the environment for toxins may soon be easier with a tiny chemical sensor developed by scientists at Los Alamos National Laboratory. Most chemical microsensors use thin polymer films that absorb gases from the air and undergo some kind of change, such as in color or electrical conductivity. But they're short-lived and aren't very sensitive or specific in identifying contaminants.

Instead of polymer films, the Los Alamos system uses tiny bucket-shaped molecules made of cyclodextrin, a component of starch. The buckets are glued to a sensing element called a transducer by a strong silicon-oxygen compound called organosilane. When a suspect chemical fits into the bucket, the added mass of the trapped "guest" causes changes in the electrical signal in the transducer that can be picked up by a recording device. The buckets can be made in various sizes and chemically tailored to sense different chemicals. Once a test is complete, it's easy to empty the buckets and start over. The Los Alamos scientists have applied for a patent and have had preliminary talks with manufacturers, including Motorola Inc.EDITED BY RUTH COXETER