Researchers at Ecole Polytechnique Fédérale de Lausanne have developed an optical chip that can identify individual biomolecules in small sample volumes, using an ordinary camera and metasurfaces, an emerging technology in photonics. The researchers hope that their technology could pave the way for diagnostic chips that can identify trace amounts of disease biomarkers in blood or saliva. Such technology may allow users to conveniently assess their health at home and to receive comprehensive screenings at the clinic.
The device consists of an ultrathin optical chip, which employs metasurfaces to identify individual molecules. The surfaces are sheets studded with millions of nanostructures arranged in particular patterns. The structures “squeeze” light into small areas, resulting in “optical hotspots”.
When the chip is illuminated, the light at the hotspots changes wavelength if it encounters a molecule there. This change in wavelength tells the researchers the identity of the molecule. Once a sample has been loaded into the chip, the researchers use a standard CMOS camera and different colored lights to take images under different conditions. They then use image analysis software to assess the resulting images and to count the number of specific molecules in a sample.
“We then use smart data science tools to analyze the millions of CMOS pixels obtained through this process and identify trends,” said Filiz Yesilkoy, a researcher involved in the study. “We’ve demonstrated that we can detect and image not just individual biomolecules at the hotspots, but even a single graphene sheet that’s only one atom thick.”
As the device can detect such small amounts of specific biomolecules, it could provide an early warning system for disease. “Optical sensors could play a major role in addressing future challenges – particularly in personalized medicine,” said Hatice Altug, another researcher involved in the study.
Study in Nature Photonics: Ultrasensitive hyperspectral imaging and biodetection enabled by dielectric metasurfaces…