Researchers at the Australian National University (ANU) have developed a simple, inexpensive method for creating lenses that would open doors for researchers, students and hobbyists.
Lenses are usually made by either grinding and polishing a disk of glass until it is curved or with molds — both costly, complex methods, the former of which has been practiced for hundreds of years. This new process will allow scientists to bake their own lenses by harnessing the power of gravity with only an oven, a glass slide and polydimethylsiloxane (PDMS) — a common, gel-like polymer.
"What I'm really excited about is that it opens up lens fabrication technology," Steve Lee, lead author of the study that helped develop this technique, said in a statement. "It's a low cost and easy lens-making recipe."
A bit of PDMS is dropped on the slide, which then hardens when it is baked at 70 degrees Celsius — not even as warm as an oven would need to be to bake a cake. This will create a base for the lens. When another drop of PDMS is added to the base and the slide is flipped over, gravity will give it a curved shape. Baking the lens again will solidify it. This process can be repeated to fine-tune the lens' shape and increase its quality.
Medical devices are an obvious use-case for the new lenses. Dermoscopes, devices used to magnify and illuminate skin lesions when diagnosing diseases such as melanoma, for example, normally cost at least $500. This new process, however, has helped researchers develop a cheap alternative that costs about $2 and can be attached to a smartphone camera, according to Lee — a boon for doctors in rural areas or developing regions. Biologists could also implant the lenses in mice to study cells in vivo — in an organism — a process usually avoided because of how expensive it is.
Lenses only a few millimeters thick with a magnification power of 160 times and a resolution of approximately 4 microns have been made so far. This is nearly on par with a good number of commercial microscopes, but given the low cost of the lenses there are opportunities to make more resources available to students or for hobbyists to experiment on the cheap.
Researchers are currently working to make larger lenses and increase their effectiveness. The ANU study was published last month in Biomedical Optics Express.