Illustration of chip sensor system. (Credit: UCSD Jacobs School of Engineering)

Illustration of chip sensor system. (Credit: UCSD Jacobs School of Engineering)

Fewer soldiers will die on the battlefield if two U.S. researchers succeed in developing a project called “field hospital on a chip.” The project entails creation of a minimally-invasive sensor troops will wear into battle. Able to monitor, detect, diagnose and administer medication, the sensor will deliver life-saving treatment to soldiers long before medics can ever reach them, the researchers claim. “Since the majority of battlefield deaths occur within the first 30 minutes after injury, rapid diagnosis and treatment are crucial for enhancing the survival rate of injured soldiers,” says Joseph Wang, one of two primary researchers who will share a four-year, $1.6 million grant from the Office of Naval Research to develop the project.

Wang, a nanoengineering professor at Jacobs School of Engineering, at the University of California, San Diego, explains how the hospital chip project differs from his earlier work that involved tracking glucose levels via a patient’s perspiration: “Today’s insulin and glucose management systems for patients with diabetes don’t include smart sensors capable of performing complex logic operations,” he says. He stresses that the new sensor will be different because it will “monitor biomarkers and make decisions about the type of injury a person has sustained and then begin treating that person accordingly.” The sensor system Wang hopes to develop will continuously monitor a soldier’s blood, sweat and tears for multiple biomarkers. Fluctuating combinations and amounts of these biomarkers – glucose, lactase, oxygen and the stress hormone-neurotransmitter norepinephrine – will signal that shock, trauma, fatigue, brain and other injuries have taken place.

Sensors with ‘enzyme smarts’: Wang’s co-researcher, Evgeny Katz of Clarkson University in Potsdam, N.Y., is responsible for developing the logic system that will enable the sensor to measure the biomarkers and diagnose injury based on their variables. As Clarkson’s Milton Kerker Chaired Professor of Colloid Science, Katz has paved new ground in developing enzyme-driven logic systems. To date, however, his systems have worked in solution only. His and Wang’s challenge is to find a way to impart enzyme-driven logic to sensors worn by humans. Wang believes they can do this by creating electrodes that contain a combination of enzymes. The electrodes will not only act as conductors, they also will act as transducers, translating their enzymatic reactions into a binary code. The 1s and 0s will identify the type of injury that has occurred and match it to an appropriate diagnosis. The diagnosis will activate drug delivery ion based on predetermined treatment plans, the researcher explains. On JSE’s website, Wang offers this perspective of his sensor system at work:

“If an injured soldier were to enter a state of shock, enzymes on the electrode would sense rising levels of the biomarkers lactate, glucose and norepinephrine. In turn, the concentrations of products generated by the enzymes would change – higher hydrogen peroxide, lower norepi-quinone, higher NADH and lower NAD+. This will cause the built-in logic structure to output the signal “1,0,1,0,” which points to shock and will trigger a predetermined treatment response.”

Game plan: Wang expects to have a prototype of the sensor completed in about four years. It’s a tall order but, if successful, Wang says the sensor’s benefits are sure to extend beyond the battlefield. He predicts, for instance, that the sensor can easily be adapted to detect, diagnose, treat and prevent potential heart attacks, strokes and other life-threatening medical conditions.