Sweat looks promising for noninvasive health monitoring

March 15, 2019

Making a revolutionary biosensor takes blood, sweat and tears.

And saliva, of course.

Jason Heikenfeld, a professor at the University of Cincinnati, examined the potential of these biofluids to test human health with tiny, portable sensors for the newspaper. Nature Biotechnology.

Heikenfeld develops wearable technology in his Novel Device Lab at the College of Engineering and Applied Science of the UC. Last year, his lab created the world's first continuous test device that removes perspiration as effectively as blood, but non-invasively and over many hours.

"Ultimately, human biology itself is limiting technological advances in the field of wearable equipment," says the study.

Remarkably, many innovations in the field of biosensors and sweat technology have been developed in Cincinnati. The first glucose meter for diabetes has been marketed in the region. Odorono, inventor of the world's first antiperspirant, was a Cincinnati physician, Abraham Murphey.

"We have a solid story in this area here – it's really fascinating," said Heikenfeld.

Heikenfeld attributes the hard work of his team to the success of his laboratory.

"We have been able to go far and fast here," Heikenfeld said. "We are resonating with a certain type of student.While we have brilliant professors at UC, if we did not have talented students here, this technology does not have much to do with it. would not exist, we would only speak theoretically about this potential. "

in the Nature Heikenfeld has identified four waves of discoveries in health testing. First, doctors have begun collecting and sending blood to laboratories in an invasive, tedious and time-consuming process that patients continue to experience today.

Starting in the 1980s, researchers, including Chong Ahn, a pioneering professor of unified communications engineering, developed point-of-care laboratory tests that allowed physicians to achieve immediate results. Instead of sending samples to a lab, doctors could badyze them themselves with the help of tiny, self-contained devices.

"Dr. Ahn has been at the forefront of developing these devices at the point of service," Heikenfeld said.

Now, said Heikenfeld, we are in the middle of a third wave: the continuous monitoring of health using wearable devices such as those developed by UC. These provide data over time so that doctors can track health trends instead of relying on the snapshot provided by a single blood test.

"It's super powerful because it tells me I'm better? Will I get worse?" Heikenfeld said.

Eventually, the field will see devices implanted in the body for long-term diagnosis or monitoring, he said. But researchers will first need to create robust sensors that can provide accurate information over a much longer period.

"It's the big challenge," said Heikenfeld. "The sensors react chemically themselves, so they do not last."

After examining the use of saliva, tears and interstitial fluid, Heikenfeld concluded Nature This article indicates that perspiration is the most promising alternative for non-invasive testing because it provides information similar to that of blood and its secretion rate can be monitored and measured.

Heikenfeld and his students created new sensors in a hand-sized patch of a dressing that stimulates perspiration, even when the patient is resting and resting. The sensor measures over time specific badytes that physicians can use to determine how the patient responds to drug therapy.

Sensors can be customized to measure anything from drugs to hormones to dehydration, Heikenfeld said.

Last year, the lab created the world's first continuously monitoring sensor capable of recording in sweat the same medical information that doctors have been examining for generations in the blood. This milestone is noteworthy because the continuous sensor allows doctors to track the evolution of health to see if the patient is doing better or worse. And they can do it non-invasively with a tiny patch applied to the skin that stimulates perspiration up to 24 hours at a time.

"It's the Holy Grail, for the first time we can show the blood data here, here's the sweat data – and they work great together," Heikenfeld said.

Heikenfeld and his students published their latest experimental discoveries in December in the journal Lab on a Chip. The UC study helped determine how the test subjects metabolized ethanol. The study concluded that sweat provided virtually the same information as blood to measure the presence of a drug in the body.

The latest breakthrough at UC marked the culmination of more than seven years of research, he said.

"For drugs, we can use perspiration to get an accurate measure of blood levels," said Heikenfeld. "This is important because once we can measure the concentrations of therapeutic products in the blood, we can examine the dosage of the drugs.And this could give the impression that the current dosage looks like something from the Stone age. "

Cincinnati is home to several companies that are transforming prescription, delivery and drug monitoring technologies into commercial products. The list includes Assurex Health, Enable Injections and Eccrine Systems of Heikenfeld, where he is co-founder and scientific leader.

Tongli Zhang, co-author of the study and a computer biologist, said such devices will help doctors provide personalized care. Zhang is an Assistant Professor in the Department of Pharmacology and Systems Physiology at the College of Medicine of the University of California.

"You do not give the same dose of medication to children as to adults, and we can specify a dose based on the weight of the patient," said Zhang. "But some patients may have liver or kidney failure, others could metabolize a drug ten times faster, so the same dose might be ineffective in some patients and toxic in others."

Zhang said that continuous sensors could fundamentally change treatments.

"Personalized or individualized medicine is becoming a big problem, we realize it's important, if we can understand what's going on in the body, we can tailor the treatment accordingly," he said. he declares.

UC is at the forefront of the development of new biosensors that, according to Heikenfeld, will revolutionize the way we track disease and well-being.

"CUs continue to build on our rich regional history to revolutionize diagnoses with this third wave of continuous biochemical detection," he said.