University of California Los Angeles engineers have developed a cellphone attachment they say holds promise for the rapid, inexpensive detection of pathogenic E. coli in water or liquified food samples.


The simple, portable device — a lightweight, compact attachment to an existing cellphone camera — acts much like a florescent microscope, according to a UCLA news release.

The news release explains how the gadget works: A sample is pumped into a series of small tubes in the device treated with E. coli antibodies and illuminated with battery-powered inexpensive, light-emitting diodes (LEDs). The light excites labeled E. coli particles, and the emission from quantum dots (small fragments of semiconductors often used for medical imaging) is then imaged using the cellphone camera and an extra lens. By quantifying the florescent light emission from each tube, the concentration of E. coli bacteria in the sample can be calculated. 

The E. coli-detecting device was tested successfully using a specially-prepared buffer solution and milk, and can be applicable for the detection of other pathogens (through the use of different antibodies) as well, the researchers explained.

The researchers, from the UCLA Henry Samueli School of Engineering and Applied Science, published details regarding the new device online in the peer-reviewed journal The Royal Society of Chemistry.

Authors of the research include UCLA electrical engineering postdoctoral scholar Hongying Zhu; UCLA electrical engineering undergraduate student Uzair Sikora; and UCLA associate professor of electrical engineering and bioengineering Aydogan Ozcan. Ozcan is also a member of the California NanoSystems Institute at UCLA.

The Ozcan Research Group is funded by the U.S. Office of Naval Research, the National Institutes of Health, the National Science Foundation and the U.S. Army Research Office.


Photo courtesy UCLA