Harmful microbes and
toxic micromolecules in food and drinking water can cause serious health
problems around the world. For her PhD thesis, VTT researcher Sanna Uusitalo
has developed a disposable optical test substrate for use in microbial
detection. The aim is to enable cost-effective detection of harmful microbes
and toxins.
Uusitalo developed the
optical detection of microbial cells using Raman spectroscopy to increase
measurement sensitivity via SERS (surface-enhanced Raman scattering)
amplification. SERS measurement is based on Raman scattering, whose intensity
is increased by the oscillation of free electrons in metal. In some cases, the
method can identify a sample to a precision-level of one molecule. The
disposable SERS measuring substrate is patterned using a roll-to-roll
production method and coating the substrate with thin gold plating.
"The more
sensitive the SERS process becomes in the case of challenging cell
measurements, the more applications it will have in the future. It would
provide a fast and simple method of microbial identification compared to
traditional cell cultures and enable the fast identification of microbes in
cases, say, of food poisoning, or rapid purity analysis in food industry
production facilities," says Uusitalo.
She believes that the
first general application of the method will be in explosives detection or the
analysis of environmental toxins. Portable Raman measuring devices are already
on the market for the analysis of larger sample volumes. Future R&D will
also lead to portable SERS measuring devices for measuring very low sample
volumes.
Posted by Dr. Tim Sandle