New ‘glow’ detectors easily identify toxins, pathogens or explosives

Researchers at MIT have developed new detectors that could provide easy visual identification of specific chemicals — whether toxins, disease markers, pathogens or explosives.

New advance could lead to even smaller features in the constant quest for more compact, faster microchips.

The system visually signals the presence of a target chemical by emitting a fluorescent glow.

The approach combines fluorescent molecules with an open scaffolding called a metal-organic framework (MOF).

This structure provides lots of open space for target molecules to occupy, bringing them into close proximity with fluorescent molecules that react to their presence.

The findings in a paper by assistant professor of chemistry Mircea Dinca, with postdoc Natalia Shustova and undergraduate student Brian McCarthy, published online in November and to appear in a forthcoming print issue.

“A lot of known sensors work in reverse,” Mircea Dinca, assistant professor of chemistry, said, meaning they “turn off” in the presence of the target compound.

“Turn-on sensors are better because they’re easier to detect, the contrast is better,” he said.

MOF materials were first produced about 15 years ago, but their amazing porosity has made them a very active area of research.

Although they simply look like little rocks, the sponge-like structures have so much internal surface area that one-gram of the material, if unfolded, would cover a football field, Dinca noted.

The findings were recently published in the Journal of the American Chemical Society.

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