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The portable CellScope prototype currently costs about $1,000, but the price could go down to about $200 US if it were manufactured on the scale of a few thousand, David Breslauer estimated. ((David Breslauer/UC Berkeley/Canadian Press))

U.S. researchers have invented a low-cost microscope-cellphone combo to diagnose and track diseases such as tuberculosis and malaria in the developing world.

With the CellScope, a health care worker could take a blood sample in a remote village, add a special liquid, take a microscope image using the cellphone's camera, and analyze it using a special cellphone application, researcher David Breslauer said in a telephone interview Tuesday.

The worker would have a diagnosis within minutes, and could send the image wirelessly to a health centre for further analysis and storage, he said.

A description of the CellScope prototype and its testing were published in Wednesday's issue of PloS ONE. Breslauer, a University of California San Francisco and University of California Berkeley graduate student, co-led the study.

"The same regions of the world that lack access to adequate health facilities are, paradoxically, well served by mobile phone networks," Dan Fletcher, the University of California professor who heads the team developing the device, said in a statement Tuesday.

That is something that health care workers can take advantage of by pairing cellphones with easy-to-use lab equipment, he added.

Breslauer estimates that the prototype devices cost about $1,000 US apiece, but the price would go down to a "couple hundred dollars," including the cellphone, if a few thousand were manufactured.

The CellScope consists of a fluorescence microscope designed to attach to a cellphone. The worker places a blood sample on a slide and treats it with fluid that specifically "tags" a certain disease agent, such as the bacterium that causes tuberculosis or the parasite that causes malaria.

Tagged bacteria light up

The tags make the bacteria or parasites light up when viewed under the microscope. That makes it easy for people with limited training to identify them.

"You don't have to deal with a messy background," Breslauer explained. "Only what you're looking for lights up."

The cellphone camera takes an image using its "night mode." With a 3.2-megapixel camera, researchers could distinguish tiny beads one-sixth the size of a human red blood cell.

The cellphone could also be used as computer, Breslauer added. With the right app, it could analyze the image and identify the disease agent itself. The researchers tested that idea by transferring the cellphone images to a laptop and using free software to count particles in the image.

The project started as an idea Breslauer came up with while taking a microscopy class from Fletcher. It took two years of work, and while the team had previously managed to take microscope images with a cellphone camera, it's only recently that they got the more complicated fluorescence optics to work.

The biggest challenge was keeping the cost of the device low while maintaining its utility, Breslauer said.

The project was funded by UC Berkeley's Center for Information Technology Research in the Interest of Society (CITRIS) and Blum Center for Developing Economies, as well as Microsoft Research, Intel and the Vodafone Americas Foundation.