Article published Diagnostics
To the nearest molecule...
LETI designs gas detectors, from ultrasensitive micro mass-spectrometers and liquid phase measurement equipment, all based on NEMS. These are opening the way to nano-diagnostics and nano-biotechnology.
“Since March, we have been "recruiting" companies to participate in our NanoProg R&D programme, in alliance with Caltech, the Californian Institute of Technology, who are pioneers in the field of NEMS (Nano Electro-Mechanical Systems), mechanical structures (sensors and actuators) on the nanometre scale”, says Jean-Christophe Gabriel, who is in charge of application of the programme for the LETI. Together, they have initiated an original partnership model: industrial partners are sponsoring research in exchange for privileged access to the R&D results and the industrial property. Three fields of applications are targeted: multiple gas detection, micro mass-spectrometry and liquid phase analysis. With a belief that miniaturisation and a sensitivity on the scale on an individual molecule can be achieved. “We foresee transferring our first demonstration units to industrial partners in the field of gas detection and micro-spectrometry within two years”, stated Jean-Christophe Gabriel. The common point of these research areas is resonance... on the nanometre scale using tiny vibrating beams for which the resonant frequency, which is a function of their mass, varies when a molecule settles on the beam, just as the note from a violin string changes when a finger is placed on it. After two years of research, the researchers are able to design 3.5 million NEMS on a 200 mm silicon wafer (60000 per mm2), using traditional microelectronic techniques. They have also shown that their nano-beams are sensitive to changes of several zeptograms (10-21 g) in vacuum, the weight of a small protein. “With 5 nano-beams, our detectors can distinguish around twenty molecules, separated beforehand by a chromatograph”, added the researcher. The objective is to miniaturise everything by including a micro-chromatograph and, in the long term with a network of NEMS, to design portable breath analysers which can discern several hundred molecules for early cancer diagnosis. These nano-beams should also make it possible to design revolutionary micro mass-spectrometers which, as their name implies, separate the components of gaseous mixtures according to their mass. Within two years, a first device will compete with the current state-of-the-art ultrasensitive detection technology, the Channel PhotoMultiplier, while also providing quantitative results. In the long term, researchers are aiming for miniaturisation and parallelisation of the system, enabling the proteins from a single cell to be analysed in 20 minutes.
