Expensive, bulky lenses have been the basis of imaging technology for centuries. Now, says Aydogan Ozcan, an assistant professor of electrical engineering, "it's time to change our thinking." By writing sophisticated image-processing software and taking advantage of the inexpensive light sensors now ubiquitous in cell phones, he may have made lenses obsolete. The lensless imaging devices that Ozcan has built achieve roughly the same resolution as standard bench-top microscopes (about a micrometer), so they can be used to count, identify, and even image living cells.

He's made prototypes mounted in cell phones to demonstrate the technology and has started a company called Microskia to develop it. The first products are likely to be simple microscopes that plug into a cell phone or laptop through a USB cord and display the magnified images on their screens; the first uses will probably be in remote medical centers, to diagnose anemia, cancer, and infectious diseases such as malaria. According to Ozcan, though, his prototypes are actually good enough to replace the large, expensive cell counters used in U.S. hospitals. --Katherine Bourzac

1. Light Detector: A microscope slide holding a sample such as blood can be mounted here, over the phone's camera, which contains a light-detecting chip. The phone's processor runs the imaging software.

2. Light Source: The black plastic tube contains light filters and a light-emitting diode powered by the phone's batteries, but no lenses. Light shines from the tube through a sample and onto the camera's imaging chip.

3. Add-on Imaging: The imaging system can be removed for a more convenient cell-phone conversation or replaced with a light source better suited to a particular imaging application.

Credit: Christopher Harting