'Baked' cheap lenses to detect disease, help research

We know that a droplet of clear liquid can act as a lens by bending light. Exploiting this natural phenomenon, researchers have developed a new 'baking' process to create inexpensive, high-quality lenses that will cost you almost nothing!

These inexpensive lenses can be used as tools in detecting diseases, scientific research in the lab, developing optical lenses and microscopes.

"What I am really excited about is that it opens up lens fabrication technology," says Steve Lee from Australian National University (ANU).

All that is needed is an oven, a microscope glass slide and a common, gel-like silicone polymer called polydimethylsiloxane (PDMS).

First, drop a small amount of PDMS onto the slide. Then bake it at 70 degrees celsius to harden it, creating a base.

Then, drop another dollop of PDMS onto the base and flip the slide over.

Gravity pulls the new droplet down into a parabolic shape.

Bake the droplet again to solidify the lens.

"More drops can then be added to hone the shape of the lens that also greatly increases the imaging quality of the lens. It is a low cost and easy lens-making recipe," Lee explained.

The researchers made lenses about a few millimeters thick with a magnification power of 160 times and a resolution of about 4 microns (millionths of a metre).

"We are quite surprised at the magnification enhancement using such a simple process," he noted.

The researchers have also built a lens attachment that turns a smart phone camera into a dermascope, a tool to diagnose skin diseases like melanoma.

While normal dermascopes can cost $500 or more, the phone version costs around $2.

A similar smart phone-based tool can also help farmers identify pests out in their fields.

The lenses used in low-cost mobile microscopes can be distributed to kids for educational or outreach purposes.