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
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
2013 MEMS 621-624.