High-resolution silicon polymer lenses can be baked in conventional ovens and attached to smartphones to make an inexpensive microscope. The discovery could help farmers check their crops for pests and enable ordinary people to examine their own skin for signs of disease like melanoma, according to researchers at the Australian National University (ANU) Research School of Engineering. A single droplet lens suspended on a fingertip. Courtesy of Stuart Hay, Australian National University. Creating the lenses is a simple process, according to ANU professor Dr. Woei Ming “Steve” Lee. “We put a droplet of polymer onto a microscope cover slip and then invert it. Then we let gravity do the work, to pull it into the perfect curvature,” he said. “By successively adding small amounts of fluid to the droplet, we discovered that we can reach a magnifying power of up to 160× with an imaging resolution of 4 µm.” The material used, polydimethylsiloxane (PDMS), is the same as that used for contact lenses, and won't break or scratch. The droplets are cured by baking them at 70°C. Lee collaborated with Dr. Tri Phan of the Garvan Institute of Medical Research in Sydney to create a lightweight, 3-D-printable frame to hold the lens, along with a couple of miniature LED lights for illumination and a coin battery. The device constitutes a do-it-yourself dermascope and costs about $2 to make, the researchers said. “This is a whole new era of miniaturization and portability,” Phan said. “Image analysis software could instantly transform most smartphones into sophisticated mobile laboratories.” The work is published in Biomedical Optics Express (doi: 10.1364/BOE.5.001626).