A new cellphone–based imaging and sensing platform has emerged in academia that can detect the presence of the bacterium Escherichia coli in either food or water. The device can also be adapted for homeland security for specific detection of several other biotoxins or pathogens.
UCLA engineers said the device operates like a fluorescent microscope. Samples of food or water are first collected in special glass tubes treated with E. coli antibodies and covered with quantum dots (semiconductors often used for medical imaging).
By measuring the excitement of the quantum dots, the device is able to calculate the concentration of E. coli in the sample. The method has been tested successfully both in a specially prepared solution and in milk samples.
“This technology creates opportunities to bring advanced micro-analysis and diagnosis tools to remote locations using computational imaging techniques running on the cellphone,” said UCLA electrical engineering and bioengineering professor Aydogan Ozcan.
Ozcan said the E. coli platform can also be applicable to other pathogens of interest through use of different antibodies.
E. coli are rod-shaped bacteria commonly found in the lower intestine. Most E. coli strains are harmless, but some can cause serious food poisoning in humans. For instance, a novel strain of E. coli caused a widespread outbreak of foodborne illness in northern Germany in the spring of 2011.
E. coli can easily contaminate food and drinking water. In the absence of proper agricultural cleansing methods, or in the hands of terrorists, E. coli poses a significant public health threat. Hospitalization and death can occur. As few as 10–100 E. coli bacteria can kill the cells of the intestinal lining, destroy the kidneys and cause blood clots in the brain, as well as seizures, paralysis and respiratory failure.
Ozcan said cost-effective and field-portable microscopy and cytometry tools such as this one, running on or attached to any cellphone with a camera device, could be used at point-of-care facilities by healthcare professionals or by mobile telemedicine units that conduct health screening in the field.
“Portable devices like this also can be used in battlefield settings to test the quality of food or water resources or to test bodily fluids of soldiers for health markers, much like a Star Trek tricorder,” Ozcan said.