Smartphone Snaps Nanoparticle Pics

By attaching a small, inexpensive gadget to the back of a smartphone, scientists have created a sensitive handheld fluorescence microscope. The attachment allows the phone’s camera to take pictures of fluorescently labeled nanoparticles and virus particles, making the phone a potentially useful portable diagnostic tool for health care workers in developing countries (ACS Nano 2013, DOI: 10.1021/nn4037706). The device, designed by Aydogan Ozcan of UCLA and colleagues, consists of a laser diode to excite fluorescent dyes and a compact system of lenses and filters that remove background noise created by the laser light. The team used the microscope to detect human cytomegalovirus particles, which are between 150 and 300 nm in diameter, and polystyrene beads, which at about 100 nm in diameter were the smallest objects that could be detected. According to Ozcan, the mini microscope is the first portable, cell-phone-based imaging system sensitive enough to resolve individual nanoparticles and viruses. Ozcan started a company called Holomic to commercialize the device, and his group has created smartphone apps for data analysis.