An inexpensive, little optical lens can turn any cheap old smartphone into a microscope. A penny’s worth of materials can achieve high resolution images of one micrometer length and at a magnification of 120x.
Developed by a University of Houston team led by Yulung Sung, the lens is made by dropping polydimethylsiloxane (PDMS) -- a polymer with the consistency of honey -- onto a preheated surface to harden it. Each droplet is produced by hand using a device that works like an inkjet printer (pictured above). The curve of the lens decides the magnification of the scope, and this depends on how long and how hot the polymer is heated. It’s flexible like a soft contact lens, but thicker, and it can be attached directly to the smartphone lens -- no other device is required. The adhesion is strong, but it’s detachable and reusable.
To test their lens, the team captured images of a human skin-hair follicle slide using their smartphone-PDMS system and also an Olympus IX-70 microscope. Their smartphone lens at a magnification of 120 was comparable to the Olympus at 100x magnification. With digital software, the image could be enhanced even further.
Here’s a comparison of human skin and hair follicle cross-section slides imaged with an Olympus IX-70 microscope at 40x magnification (a), 100x magnification (b), 200x magnification (c), and with a Nokia Lumia 520 smartphone and the PDMS lens system (d). The bottom row shows each of the magnified regions.
Y Sung et al., J. Biomed. Opt. 2015. Magnifications using an Olympus IX-70 microsope, and with a modified smartphone.
This microscope was a result of “a $20 phone and a 1 cent lens,” Sung says in a news release. That penny covers just the cost of material. To manufacture the lenses in bulk, the team estimates that it would cost about 3 cents each. Microscopes can cost tens of thousands more. Traditional lenses are manufactured with mechanical polishing or injection molding of glass or plastics, while liquid lenses require extra work to remain stable or an additional attachment to stick onto the smartphone.
A lens like this could be incredibly useful for all sorts of settings, from classrooms with younger children to isolated clinics lacking funds and facilities. And the images would be easy to share!
The work was published in the Journal of Biomedical Optics last month.
[Via University of Houston]