Scientists seeking an inexpensive way to turn a cell phone into a high powered, high quality microscope that can be used to identify biological samples in the field, turned to a colleague at the U.S. Department of Energy's Pacific Northwest National Laboratory (PNNL), Richland, WA. Using a 3D printer and a small glass bead, she was able to accomplish just that.

An inexpensive 3D-printed microscope attached to a cell phone shows the epidermis of an onion magnified 350 times.

Using glass spheres as a microscope lens is not a new idea, optically, but the small size of the housing combined with very high magnification and extremely low cost is what makes this device practical.

"We believe it can fill a need for professional first responders, and also for teachers and students in the classroom, health workers, and anyone who just wants an inexpensive microscope readily available," said creator Rebecca Erikson, an applied physicist.

There are a few other devices that use a variety of approaches to leverage a cell phone camera into a microscope, but many are bulky, expensive, hard to align, or are lower powered. The PNNL team developed an inexpensive version that can magnify a sample by 1,000 times. For specific applications, lower magnifications are easily achievable, they say.

PNNL has made thedesign specifications available to the public, free of charge, so that anyone with access to a 3D printer can make their own microscope. The microscope slips over the camera lens of the cell phone and is no thicker than a phone case. It's designed to fit several popular cell phone brands and tablets. The material cost, not including the printer, is less than $1 so, should the slip-on microscope get contaminated, throwing it away is no great loss.

Using inexpensive glass beads traditionally used for reflective pavement markings at airports, the PNNL team has demonstrated 1,000x magnification, which is necessary to see tiny pathogens. They have also made a 350x version, which is adequate to identify parasites in a blood samples or protozoa in drinking water.