Nanosensors detect cancer from breath
25 April 2014
A collaboration of researchers in Switzerland and Japan has developed portable cancer detection units using coated nanocantilevers for diagnosis from breath.
The sensor design originates from conventional piezoresistive cantilever devices. Chemical layers coated on cantilevers absorb specific compounds and cause deflection of the cantilevers. These deflections can be measured through the change in electrical resistance at piezoresistors.
These piezoresistive cantilever-type sensors have suffered from limited sensitivity, but structural optimization has led to a membrane-type surface stress sensor (MSS) that achieves a significant improvement in sensitivity and stability. The MSS is composed of a thin silicon membrane (typically 2.5 μm thick and 500 μm in diameter) suspended by four piezoresistive beams attached to the circumference.
Frederic Loizeau at the Ecole Polytechnique Federale de Lausanne, Hans Peter Lang at the University of Basel in Switzerland, Genki Yoshikawa at the National Institute of Materials Science in Japan and their colleagues fabricated an array of MSS and coated them with different polymers to absorb various chemical compounds in breath samples. Reporting at the 26th IEEE International Conference on Micro Electro Mechanical Systems (IEEE MEMS 2013), the researchers presented that MSS could distinguish, in a double blind trial, the breath of four cancer patients from four healthy people.
Frederic Loizeau et al. Piezoresistive membrane-type surface stress sensor arranged in arrays for cancer diagnosis through breath analysis. 2013 MEMS 621-624.