The U.S. Army has awarded a team of researchers led by Judith Su, University of Arizona associate professor of biomedical engineering and optical sciences, $2.1 million to build a handheld version of her record-breaking FLOWER sensing device for active military personnel.

The device picks up target compounds at zeptomolar (10 to the power of negative 21) concentrations, an astonishingly minuscule amount of 600 particles per liter. FLOWER is useful for drug testing and a wide variety of other applications, such as health diagnostics. 

The military expects it may also preserve the lives of active-duty service members. 

Unprecedented sensitivity

Su received $2.8 million from the U.S. Defense Threat Reduction Agency four years ago to conduct phase 1 research for her project, which is called FORWARD: FLOWER-Based Optical Resonators for Widely Applicable Reagent Detection. 

Phase 1 tested FLOWER's detection capabilities on tiny amounts of airborne chemical warfare agents. Su, principal investigator at the university's Little Sensor Lab and a Craig M. Berge Faculty Fellow, said FLOWER detected part-per-million concentrations of DIMP, a byproduct of sarin, a highly toxic nerve agent that is clear, odorless and tasteless. It is incredibly difficult to detect without advanced tools, making it a dangerous obstacle for the U.S. Army.

"We were also looking at things like nitric oxide, ammonia, formaldehyde, all these different chemicals," Su said. "We were able to demonstrate record levels of sensitivity."

Unlike other sensing devices, FLOWER doesn't require compound tagging, which is the addition of a fluorescent or radioactive tag to make a target compound stand out during testing. This advantage potentially makes FLOWER a cost-effective solution to identify gas particles on the go, Su said. 

Saving lives – in battle and at home

Advancing into phase 2, Su will develop a prototype that takes FLOWER sensors off the lab bench and into the general population. Anyone could be an operator.

"We're making it a translatable device from the laboratory to real-world chemical sensing solutions," Su said.

"We want to make it as accessible as possible," she said. "Military personnel who want to know if it's safe to enter a room can see a red or green light response."

Euan McLeod, associate professor of optical sciences and Su's collaborator, said the device allows for early detection and will be more sensitive than anything the Army is currently using.

"Being far away from a toxic gas, there might be a little bit of it in the air, but it's such a low concentration that a normal sensor couldn't sense it," McLeod said. "This will keep people safer by giving them an early warning at a longer distance from the source."

McLeod and Su will collaborate to miniaturize FLOWER's power over the next three years.

By bringing FLOWER into the hands of active military, Su sees far-reaching implications for a portable device.

"If you can make a portable sensor for the military, that can also be useful in hospitals or point-of-care applications at home if you want to monitor your health," she said. "With a handheld, you could just spit into this device, and it could interface with your cellphone to give a readout."