The process is simple and much shorter than other methods of lens-making, which require molds, grinding and polishing. Applying an adhesive on the back of the lens can hold it onto a smartphone camera lens, turning the phone's camera into a microscope.  As a result, Shih and his colleagues say they can churn out the lenses quickly, and they cost only about 3 cents to make.  The team published its findings in the Journal of Biomedical Optics.  A portable, smartphone-based microscope presents many advantages—laboratory microscopes are bulky and expensive. Cheap microscopes could be used in schools, and Shih said local teachers have already expressed interest in using them in their classrooms.  Read MoreMicrosoft is giving users the finger…literally  "I am currently funded by the National Science Foundation, and one of the missions of the NSF is to do outreach with K-12 schools," Shih said. "So this could be a very good tool, and the fact that we can achieve a very high throughput and make these cheaply means that we don't even have to ask them to pay for these. We can donate these lenses, and hopefully we work with them to develop some curricular modules."  There are commercial applications as well, the researchers said. The device would allow civil engineers to analyze concrete for cracks without having to cut out samples and send them back to labs. The scientists have also talked with geologists about using them in field research.  The team is looking into improving the lenses for medical uses. Sung said they have already fielded interest from eye doctors. He said patients with potentially dangerous skin conditions could use the lenses to send pictures to their dermatologists.  The researchers are looking into slight changes they could make to the substance that would expand its uses. For instance, they're investigating the addition of colored dyes that could turn the lens into a light filter for more specialized uses.  Read MoreBill Gates: Capitalism is the wrong incentive here  "While I was waiting for this interview I had a few dollar bills in front of me, and I could count the number of hairs on Abraham Lincoln's beard, on the $5 bill," Shih said. "I can see the tiny writing around the edges of the White House on the back of a $20 bill. So, I think this is just a very fun project with a lot of creative uses. Maybe they can use it to spot counterfeit bills."  The group tried to raise $12,000 last year on crowdsourcing site Indiegogo for equipment, but ended up raising only a quarter of that. Apart from developing their manufacturing process, they also hope to find ways to either market the lenses for commercial uses—or simply get them into people's hands.  "I would like to see them be useful," Sung said. "That is more important than just being something we can sell."
Researchers at the University of Houston have developed cheap and disposable lens that can turn inexpensive smartphones into microscopes.