Microscope lenses are typically made either by grinding and polishing glass discs, or pouring polymers into molds – both techniques can be quite involved, which is reflected in the price of the finished product. Now, however, a scientist from Australian National University has devised a new lens-making process, in which drops of silicone are simply baked in an oven. The resulting lenses can be used for a variety of applications, yet are worth less than one cent each.
Developed by Dr. Steve Lee, the process begins with a drop of a gel-like silicone polymer known as polydimethylsiloxane (PDMS) being placed on a glass microscope slide. That drop is then baked on the slide at 70ºC (158ºF), causing it to harden into a flat disc that will serve as the base of the lens.
Another drop of the gel is then placed on that base, and the slide is returned to the oven. This time, however, the slide is flipped over so that the PDMS is on its underside. This causes the second drop of polymer to hang down in a parabolic droplet as it bakes. Once that droplet has hardened, others can be added over top of it, until the optimum lens shape has been achieved.
Lee and his team also created a 3D-printed attachment, that allows the lenses to be used with a smartphone camera. With a magnification power of 160 times and a resolution of about four microns, the resulting US$2 microscope is powerful enough to be used as a skin-examining dermascope – traditional models of which can cost up to $500.
That dermascope should be commercially available within a few months, for use in developing nations. A pest-identifying smartphone tool for farmers is also in the works.
Given the low cost of the lenses, Lee hopes that they could additionally find their way into things like educational toys. He is currently working on making larger versions of them and increasing their optical performance, which currently still isn't as good as that of many conventional microscope lenses.
A paper on his research was recently published in the journal Biomedical Optics Express.
Source: The Optical Society
