UCLA engineers create cell phone-based sensor for detection of E. coli in water and food

Researchers from the UCLA Henry Samueli School of Engeineering and Applied Science have developed a new cell phone–based fluorescent imaging and sensing platform that can detect the presence of the bacterium Escherichia coli in food and water. The engineers combined antibody functionalized glass capillaries with quantum dots as signal reporters to specifically detect E. coli particles in liquid samples using a lightweight, compact attachment to an existing cell-phone camera. Using battery-powered, inexpensive light-emitting diodes (LEDs), the researchers can excite/pump labeled E. coli particles captured on the capillary surface; there, emissions from the quantum dots can be imaged with the cell-phone camera, using an additional lens inserted between the capillary and the cell phone. The cost-effective cell-phone attachment acts as a florescent microscope, quantifying the emitted light from each capillary after the specific capture of E. coli particles within a sample. This study illustrates the promising potential of a cell phone–enabled, field-portable and cost-effective E. coli detection platform for the screening of both water and food samples.