The World Health Organization estimates that 1.3 million people worldwide died from tuberculosis in 2008. It’s definitely a disease to be taken seriously, so when people in remote locations are being tested for it, it’s best if they don’t have to wait for their samples to be processed at a distant lab. That’s why medical device designer Andrew Miller, when he was still an undergraduate at Houston’s Rice University, developed the portable, battery-operated Global Focus fluorescence microscope. In a paper published this Wednesday, Miller and his co-authors described how the US$240 Global Focus is able to detect TB-positive sputum smears just as well as laboratory microscopes worth over $40,000.
Miller built the original 1,000X microscope last year, as his bioengineering senior design project. His goal was to make a portable microscope that could be used in developing countries, where there was limited access to lab equipment and/or electricity. He built it from off-the-shelf parts, enclosed in a rugged plastic shell created with a 3D printer. Light was provided by a top-mounted LED flashlight. This year, it won him Rice’s Hershel M. Rich Invention Award, an annual engineering award presented to faculty or students for original inventions. This is the first time it has ever been presented to an undergraduate project.
Since graduating, Miller has continued work on the Global Focus. He started by upgrading the plastic shell to aluminum, for better stability. With help from The Methodist Hospital Research Institute (TMHRI) he has also run a laboratory trial, in which 63 smears from suspected TB carriers were analyzed both by his device, and TMHRI's much more sophisticated fluorescence microscope. In 98.4 percent of the samples, the two microscopes showed similar findings.
"This is hugely significant as a point-of-care tool clinicians can use for tuberculosis patients, whether they're in Asia or Africa or even in West Texas," said Edward Graviss, director of the TMHRI Molecular Tuberculosis Laboratory. "The first identification of TB is usually made with a smear, and it will be good to know that in the field instead of having to wait three or four days to get the smear to a lab.”
Rice and Miller have now partnered with 3rd Stone Design, a medical device consultant, to produce 20 microscopes for use in field trials next month. To help untrained clinicians make accurate diagnoses, a new team of Rice students is also developing image processing software for smart phones.