Developments to Watch
HOW TO FIND A LAND MINE IN FADING LIGHT
NEW FLUORESCENT COMPOUNDS DEVELOPED BY A RESEARCH GROUP AT MASSACHUSETTS INSTITUTE OF TECHNOLOGY may soon be used to sniff out some of the estimated 120 million unexploded land mines hidden around the world. The polymers, which glow yellow, are described in the Nov. 25 issue of the Journal of the American Chemical Society. They are sensitive enough to detect extremely dilute trace vapors of TNT, which waft into the air directly above a buried land mine.
When these highly sophisticated chemical sensors bind to TNT, the polymers' fluorescent intensity decreases significantly. The binding of just one molecule of TNT is enough to cause a measurable dimming of the polymers. That means they can be used to detect TNT in concentrations as dilute as 10 to 100 parts per billion.
Timothy M. Swager, the lead author of the study, believes these novel polymers could be used in low-cost, handheld mine detectors. He is working with a Stillwater (Okla.)-based company called Nomadics Inc. to develop a prototype. In the future, the polymers, and the portable detection devices that will contain them, could also find a home at airport security checkpoints, alerting inspectors to hazardous chemicals, firearms, and drugs such as cocaine and heroin, all of which give off trace vapors.BY ELLEN LICKINGReturn to top
THE CELL OF A NEW MACHINE
LIVING CELLS ARE FANTASTICALLY EFFICIENT FACTORIES, constantly procuring chemicals from their environment and assembling them into complex proteins. They even contain minuscule molecular pumps and motors to transport materials in, out, and around the cell. Scientists would like to intervene in these processes and direct them toward delicate and specific engineering goals--such as delivering toxins to tumor cells or monitoring microbial threats to crops.
Now, researchers are taking the first small steps toward such interventions. Carlo D. Montemagno, an assistant professor of biological engineering at Cornell University, says he has modified the surface of a cellular pump that measures just 40 atoms across. This modification allows him to attach artificial components for controlling it. Addressing the Foresight Conference on Molecular Nanotechnology in Santa Clara, Calif., in mid-November, he described a blueprint for a hybrid cellular machine that engineers can turn on and off as they please. Such a device could be programmed to target renegade cancer cells, glom on to them, and shoot them up with chemicals that would be too toxic to release into the general bloodstream.BY ELLEN LICKINGReturn to top
DRAWING A BEAD ON RECYCLABLES
A NEW POINT-AND-SHOOT DEVICE CALLED THE RP-1 Polymer Identification System promises to cut down on the billions of pounds of plastic that are annually land-filled or incinerated because they can't be recycled until they're identified and meticulously sorted. The device, which looks like a laser-tag gun tethered to a desktop computer, was developed by engineers at Purdue University and is being marketed by West Lafayette (Ind.)-based SpectraCode. Visteon Automotive Systems, Ford Motor Co.'s automotive component operation, is using the device to pick out plastic components from junked cars, and Detroit recycling facilities are using it to sort other plastics such as dry-cleaning bags and shrink-wrap packaging.
The RP-1 works like a bar-code reader--only instead of magnetic lines, the instrument "reads" molecular structures in the plastic. Typically, the system takes less than a second to identify a piece of plastic. That means the RP-1 has the potential to sort through 500 tons of material a day. "It's a fabulous piece of equipment," says Tony J. Bruchs, Senior Recycled Materials Engineer at Visteon.BY ELLEN LICKINGReturn to top