A watch-sized device can analyze sweat and recognize signs of an impending and deadly cytokine storm caused by Covid-19 and other infections.
The phenomenon occurs when chemicals in the bloodstream called cytokines multiply rapidly and get out of control.
These little chemicals are designed to limit and control the immune system, and when they go wrong, it can lead to inflammation and organ damage.
Early in the COVID-19 pandemic, doctors recognized that patients who developed a ‘cytokine rush’ were often the sickest and most at risk of death.
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A watch-sized device can analyze sweat and recognize signs of an impending and deadly cytokine storm caused by Covid-19 and other infections
A cytokine rush happens when cytokines in the body rush through the bloodstream, creating other immune cells, leading to organ damage
Researchers at the University of Texas at Dallas made sensor strips with antibodies to seven pro-inflammatory proteins and tested them on six healthy people and five people with flu, another virus that can trigger a cytokine storm.
Two of the sick people showed elevated cytokine levels, while all participants had cytokines in their sweat that matched the expected values based on previous research.
An early warning system would allow doctors to administer steroids quickly, reducing the risk of the cytokine rush getting out of control, ”the researchers said.
“Especially now in the context of COVID-19, if you could track pro-inflammatory cytokines and see them upwards, you could treat patients early, even before they develop symptoms,” said study author Shalini Prasad.
Early detection is important because once a cytokine storm is unleashed, the excessive inflammation can damage organs, resulting in serious illness and death.
In contrast, if doctors could administer steroid or other therapies as soon as cytokine levels start to rise, hospitalizations and deaths could be reduced.
While blood tests can measure cytokines, they are difficult to perform at home and cannot continuously monitor protein levels.
Cytokines are excreted in the sweat in lower concentrations than in the blood.
To catch enough sweat for testing, scientists asked patients to exercise, or they applied a small electrical current to the patient’s skin.
However, these procedures can themselves alter cytokine levels, according to Prasad.
“When it comes to cytokines, we found that you have to measure them in passive sweat,” said the lead researcher.
“But the big challenge is that we don’t sweat a lot, especially in air-conditioned environments,” she says.
The team estimates that most people produce only about 5 microlitres, or one-tenth of a drop, passive sweat in 0.5-inch skin in 10 minutes.
Therefore, the researchers wanted to develop an extremely sensitive method to measure cytokine levels in small amounts of passive sweat.
They draw on their previous work on a wearable sweat sensor to track markers of inflammatory bowel disease (IBD).
The wristwatch-like device measures levels of two proteins that peak during IBD flare-ups and when worn on the arm, passive sweat diffuses into a sensor strip.
Early detection is important because once a cytokine storm is unleashed, the over-inflammation can damage organs and cause serious illness and death, says study author Shalini Prasad (center of photo)
Researchers at the University of Texas at Dallas created sensor strips with antibodies to seven pro-inflammatory proteins and tested them on six healthy people and five people with flu, another virus that can trigger a cytokine storm
The sensor, which contains two electrodes, is covered with antibodies that bind to the two proteins, a process that changes the electrical current going to the reader.
The reader then transfers the data wirelessly to a smartphone app that converts electrical measurements into protein concentrations.
After a few minutes, the old sweat spreads and newly secreted sweat enters the strip for analysis.
For their new cytokine sensor, known as SWEATSENSER Dx, the researchers made sensor strips with antibodies against seven pro-inflammatory proteins.
The SWEATSENSER Dx was sensitive enough to measure cytokines in patients taking anti-inflammatory drugs, which secrete far fewer chemicals.
The device tracked cytokine levels for up to 168 hours before the sensor strip needed to be replaced.
EnLiSense, in collaboration with the researchers, is now planning clinical studies of the cytokine sensor in people with respiratory infections.
“Access to COVID-19 patients has been challenging as health professionals are overwhelmed and don’t have time to test research equipment,” says Prasad.
“But we’re going to continue to test all respiratory infections because the trigger of the disease itself doesn’t matter – it’s what happens to the cytokines we want to monitor.”
The findings will be presented at the ACS Spring 2021 meeting.