Researchers from Purdue University and NIST have developed new technology for detection of biomarkers in breath with sensitivity approaching only few parts per billion:
The technology works by detecting changes in electrical resistance or conductance as gases pass over sensors built on top of “microhotplates,” tiny heating devices on electronic chips. Detecting biomarkers provides a record of a patient’s health profile, indicating the possible presence of cancer and other diseases.
The researchers used the technology to detect acetone, a biomarker for diabetes, with a sensitivity in the parts per billion range in a gas mimicking a person’s breath.
The researchers used a template made of micron-size polymer particles and coated them with far smaller metal oxide nanoparticles. Using nanoparticle-coated microparticles instead of a flat surface allows researchers to increase the porosity of the sensor films, increasing the “active sensing surface area” to improve sensitivity.
A droplet of the nanoparticle-coated polymer microparticles was deposited on each microhotplate, which are about 100 microns square and contain electrodes shaped like meshing fingers. The droplet dries and then the electrodes are heated up, burning off the polymer and leaving a porous metal-oxide film, creating a sensor.
Gases passing over the device permeate the film and change its electrical properties depending on the particular biomarkers contained in the gas.
Full story at Purdue: Purdue, NIST working on breathalyzers for medical diagnostics…