Cell phones have already revolutionized communication, and now they might one day do the same for food safety. A research group working under Aydogan Ozcan at UCLA has created a cell phone attachment that can calculate the concentration of E. coli in a liquid sample. The device works similarly to a fluorescence microscope, pumping the sample into a series of small tubes treated with E. coli antibodies, then measuring the excitement of quantum dots (small fragments of semiconductors) placed around them with the phone's camera and an additional lens. From this excitement, researchers can calculate the concentration of E. coli in the sample. The method was tested successfully both in a specially-prepared solution and in a glass of milk.
Ozcan's research group has been working for some time on scaling down biomedical technologies to fit on phones. Last year, they created a flow cytometer, a machine used to image cells and bacteria, that could be built for five dollars and attached to a cell phone. This latest attachment builds on the cytometer, but tests for specific pathogens rather than white blood cells, the focus of the previous study. Since E. coli presents a threat to public health worldwide, this attachment could be used as a simple and portable way to test for its presence in water or liquified food samples, and different antibodies could be used to check for other harmful bacteria. The research was published in The Royal Society of Chemistry's Analyst journal; click through to the source link for an abstract.