C&B Notes

A Disposable Microscope?

A group from Stanford is in the beta stage of developing what is effectively a disposable microscope, which they have dubbed Foldscope.  Its low cost and ease-of-use is intended to promote widespread use in places where traditional microscopes are unavailable.

The Foldscope’s non-paper components, a poppy-seed-sized spherical lens (made from bits of borosilicate or sapphire grit produced by rolling them around in tumblers that smooth-off metal parts), a light-emitting diode, a watch battery, a switch and some copper tape to complete the electrical circuit, are pressed into or bonded onto the paper.  A high-resolution version costs less than a dollar, and offers a magnification of up to 2,100 times and a resolving power of less than a micron.  A lower-spec version (up to 400X magnification) costs less than 60 cents.

The whole device weighs under ten grams, can fit in someone’s pocket, requires no external power and takes standard microscope slides.  Sliding and flexing the Foldscope’s structure with thumb and fingers lets the user move a slide around and then focus on the relevant bit of it.  The Foldscope can be adapted, by fitting it with a more powerful LED, to project what it sees onto a screen, and the design can be modified to accommodate multiple lenses or filters.  Dunk it in water, drop it or stamp on it (though not with a slide inside), and it will still work.

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Dr. Prakash sees the Foldscope’s main use as a diagnostic tool for tropical diseases.  Malaria, for example, can be caused by several species of parasite.  Knowing which is responsible for a particular case can affect the treatment chosen.  Foldscopes should also help diagnose other widespread diseases, such as schistosomiasis, loiasis and African sleeping sickness.

He hopes, too, that they will help enthuse the next generation of doctors and scientists.  His team has lined up more than 10,000 people from 130 countries to devise simple microscopy-based experiments.  A Mongolian farmer, for instance, wants to show his fellows why they should boil milk to make it safer.  An American beekeeper proposes to use Foldscopes to show apiculturalists how to identify bee-killing mites and fungi.  And a 12-year-old Qatari wants to study the Namib desert beetle, which scavenges drinking water from morning fogs.  The results, when published on the web, will become part of a manual of microscopy for anyone to use.