Portable biosensor uses smartphone camera as spectrometer

(Credit: Department of Bioengineering, University of Illinois at Urbana-Champaign)

According to the Illinois team, the spectral transmission-reflectance-intensity (TRI)-Analyser costs just $550. It can be used to test blood, urine, or saliva samples, with results comparable to clinic-based instruments that cost thousands of dollars.

"Our TRI Analyser is like the Swiss Army knife of biosensing," said Brian Cunningham, a bioengineering and electrical & computer engineering professor at Illinois.

"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."

The device operates by converting the smartphone camera into a high-performance spectrometer. It illuminates a sample fluid with the phone's internal white LED flash or an external green laser diode. The light from the sample is collected in an optical fibre and passed through a diffraction grating into the phone's rear-facing internal camera.

These optical components are all arranged within a 3D-printed plastic cradle. Using a microfluidic cartridge that slides through an opening in the back of the cradle, the TRI Analyser can measure multiple samples successively.