It's the job of doctors and other medical practitioners to save people's lives, but what happens when they aren't physically present? In that case, you put a telemedicine system to work. At least, that's the idea of Cambridge University professor Dr. George R. Whitesides.

Whitesides collaborated with his colleagues in the United States and Brazil to design a simple, inexpensive telemedicine system using mobile phones. His prototype system makes use of cell phone cameras and paper-based diagnostic tests that change color when exposed to certain disease markers.

To demonstrate the system, Whitesides and co. used paper-test strips to collect and characterize artificial urine samples. They then took pictures of the color-changing test-strips with a mobile phone camera and remotely transmitted them to an off-site expert. The said expert then measured glucose and protein levels for diagnosis.

Whitesides and his fellow researchers have said that their system may also be used for detecting disease in plants and livestock, as well as for testing food and water quality. What remains to be done is to further develop and mass-produce tests like these.