The Future of Food Safety: Bacterial Detection through a Smartphone
Researchers at MIT and the Max Planck Institute have developed a method for quick, on-site E. coli detection in food. While current food safety testing either requires days to complete or expensive equipment, this new method, paired with a smartphone and QR code, will make testing inexpensive and portable.
The new detection process uses Janus emulsions, droplets consisting of two hemispheres of different densities. In water, the less dense, hydrocarbon hemisphere sits above the denser hemisphere. In this arrangement, when looking from above, the droplets appear transparent. A surfactant molecule at the surface of the droplets will bind to a protein found in E. coli. This binding causes the droplets to clump together and change their positioning. Now, when viewed from above, they appear opaque, obscuring the QR code found below and allowing for quick detection of the bacteria.
Image Source: Figure 5b, http://pubs.acs.org/doi/full/10.1021/acscentsci.7b00021#showFigures