Tech Tuesday: Jeong-Yeol Yoon works to improve detection of detrimental chemicals in drinking water

University of Arizona researchers at the College of Engineering have developed a system of detecting perfluorinated-carbon alkyl chains with a smartphone by analyzing the flow rate (see UA23-014 on the TLA Inventions website). 

Known as “forever chemicals” because of their presence in everything from upholstery to firefighting foam, Perfluorinated-carbon alkyl substances, or PFAS, comprise around 10,000 different human-made agents that can be added to liquids to decrease surface tension with other solids, liquids and gasses. Perfluorooctanoic acid, or PFOA, is a specific type of PFAS that has been proven to cause significant environmental damage to human health. In 2024, the Environmental Protection Agency set new maximum contaminant levels for PFOA and PFAS in drinking water at four parts per trillion. In an interview with Harvard Law Today, James Pollack, a senior associate at the environmental law firm Marten Law, notes that the new EPA limits are roughly equivalent to “four drops of water in 20 Olympic-sized swimming pools.”

The current gold standard of PFOA detection relies on expensive lab-based liquid chromatography and mass spectrometry, which requires specialized training. By making detection possible via the use of a smartphone, this invention aims to lower the costs of both the technology and the training associated with PFAS detection.

Jeong-Yeol Yoon is a professor of biomedical engineering at the University of Arizona and the lead inventor behind the new detection system. Known by some as the “smartphone biosensor guy,” Yoon's interests are in “designing and building handheld devices for medical diagnostics and environmental monitoring.”

“We evaluated these molecular interactions by measuring the capillary flow velocities on paper microfluidic channels,” Yoon said. “A smartphone could capture video clips of such capillary action, assess the flow velocities, and classify PFOAs presence and concentration via machine learning, all under a cloud setting.”

Yoon’s interest in biomedical engineering was born from a conversation he had with his graduate school adviser in South Korea in 1998. He remembers that his adviser called biomedical engineering the future of all engineering disciplines. 

“It was an emerging discipline in the U.S. but not very well known in South Korea,” Yoon said. “So, I decided to pursue a biomedical engineering doctoral degree in the U.S.”

In addition to perfluorinated-carbon alkyl chains, Yoon also works on airborne micro- and nano-plastics, as well as airborne respiratory diseases such as the flu and COVID-19. Some of his technologies available to license include a sensitive, low-cost system for detecting SARS-CoV-2 in clinical saline gargle samples using a smartphone fluorescence microscope (UA21-239), a handheld sensitive rapid assay of SARS-CoV-2 infections (UA21-090), and a technology for detecting norovirus that combines a smartphone-based fluorescence microscope with an image-processing algorithm to isolate the particles aggregated by antibody-antigen binding (UA20-057).