Researchers at the University of Houston (UH) in the United States have developed an optical lens capable of converting a smartphone camera into a microscope. The low-cost device could be used by students or in clinical settings, allowing small or isolated clinics to share images with specialists located elsewhere.
Costing less than three US cents, the optical lens attaches directly to a smartphone camera to amplify images by a magnitude of 120. It is made of polydimethylsiloxane (PDMS), a polymer with the consistency of honey, dropped precisely on a preheated surface to cure. Lens curvature – and therefore, magnification – depends on how long and at what temperature the PDMS is heated.
The resulting lenses are reusable and flexible, similar to a soft contact lens, although they are thicker and slightly smaller.
‘Our lens can transform a smartphone camera into a microscope by simply attaching the lens without any supporting attachments or mechanism,’ the researchers described in a paper published in the Journal of Biomedical Optics. ‘The strong, yet non-permanent adhesion between PDMS and glass allows the lens to be easily detached after use. An imaging resolution of 1µm with an optical magnification of 120x has been achieved.’
UH researchers are not the first university team to produce cheap lenses using polydimethylsiloxane (PDMS). Last year, scientists from the Australian National University (ANU) developed a 3D printed lens attachment that turns a smartphone camera into a dermascope, a tool to diagnose skin diseases like melanoma. The researchers made lenses approximately a few millimetres thick, with a magnification power of 160 times and a resolution of about 4µm.
For the study conducted at the University of Houston, researchers captured images of a human skin-hair follicle histological slide with both the smartphone-PDMS system and an Olympus IX-70 microscope. At a magnification of 120, the smartphone lens was comparable to the Olympus microscope at a magnification of 100, according to the researchers, and software-based digital magnification could enhance it further.
The optical lens would be a cheap and convenient way for younger students to do field studies or classroom work, said Yu-Lung Sung, a doctoral candidate at UH and first author of the paper. Because the lens attaches to a smartphone, it’s easy to share images by email or text, he added.
Currently, the lenses are being produced by hand, using a device that functions similarly to an inkjet printer, but the researchers are hoping to raise money in order to produce the lenses in bulk.