Ordinarily, for the spectral analysis of peoples' blood, urine or saliva samples, lab-based machines costing thousands of dollars are required. Needless to say, such equipment isn't always available to clinicians in developing nations, or to patients monitoring their own health at home. Now, however, scientists from the University of Illinois at Urbana-Champaign have created a US$550 3D-printed device that works with an ordinary smartphone to do the same tests with just as much accuracy.
Known as the TRI (transmission reflectance intensity) Analyzer, it was developed by a team led by Prof. Brian Cunningham. According to the university, it's "capable of detecting the output of any test that uses a liquid that changes color, or a liquid that generates light output (such as from fluorescent dyes)."
To use it, treated fluid samples are placed in a microfluidic cartridge that is manually slid through an opening in the device. It then uses either the phone's white LED flash or an integrated green laser diode to illuminate the sample. The light travels through an optical fiber, through a diffraction grating, and into the phone's rear camera. An app then analyzes the image, looking for specific color changes or for fluorescence, depending on the test being performed.
Multiple analyses can be carried out in quick succession, as the microfluidic cartridge can be loaded up with several samples at once.
"Our TRI Analyzer is like the Swiss Army knife of biosensing," says Cunningham. "It's capable of performing the three most common types of tests in medical diagnostics, so in practice, thousands of already-developed tests could be adapted to it."
That said, besides its use in medical diagnostics, it could also be utilized in fields such as environmental monitoring, drug testing, manufacturing quality control, and food safety.
The technology is described in a paper published in the journal Lab on a Chip, and is available for license.