Researchers at MIT have developed a microscopic “detective” that glows when it finds molecules it has been designed to target. The tiny particles could some day be used to detect the presence of drugs, specific DNA sequences and even cancer – all from a patient’s bedside.

The tiny particles – shaped like a one-dimensional drug capsule – contain microscopic probes that can be custom-designed to detect biomolecules, such as DNA or proteins. When the targeted molecule encounters the probe, it binds to it and causes the probe to brightly glow under ultraviolet light.

Daniel Plegibon, chemical engineering graduate at MIT, said the microparticles are just as accurate, maybe even more so, than far more expensive test methods currently in use. They can be designed, encoded and manufactured all in one single process, and can test for a virtually endless variety of DNA, RNA and proteins, he said.

Plegibon and his colleague Patrick Doyle, are convinced their new microparticles could one day enhance patient care by bringing accurate diagnostic testing right to the bedside.

Each of the microparticles can be designed to probe for one or several biomolecules at once. One end of each particle is encoded with a matrix of dots – that functions much like a bar code – that identifies the target molecule. The oblong shape of the particles automatically lines them up for scanning as they pass through a reader that employs a standard microscope.

As each particle flows past the scanner, its bar code is read and the fluorescent glow – or lack of it – enables the scanner to determine not only the presence of the target molecule, but its relative quantity.

Image: MIT