An optomechanical attachment now enables smartphones to perform fluorescence microscopy measurements on DNA. The 3-D-printed device was developed by a team of investigators led by Dr. Aydogan Ozcan at the University of California, Los Angeles. A smartphone add-on enables imaging of DNA in the field. Courtesy of Aydogan Ozcan, UCLA. The device augments the phone’s camera by creating a high-contrast dark-field imaging setup with an inexpensive external lens, thin-film interference filters, a miniature dovetail stage and a laser diode for oblique excitation of fluorescent labels. The molecules are labeled and stretched on disposable chips that fit into the smartphone attachment. The attachment also includes an app that transmits data to a server at UCLA, which measures the lengths of the individual DNA molecules. This project was funded by the National Science Foundation. The results were published in ACS Nano (doi: 10.1021/nn505821y).