Researchers at the University of Texas at Dallas have designed a wearable flexible biosensor that reliably detects glucose levels in sweat.
The study, recently published in Sensors and Actuators B: Chemical, is by Shalini Prasad, et al., Professor of engineering and computer science at UT Dallas. She and her colleagues proved that the biosensors they designed were able to reliably detect glucose levels in sweat.
The team has previously demonstrated that their device is capable of detecting cortisol in sweat.
But for those with diabetes and people at risk of diabetes, self-monitoring of blood sugar is crucial to disease control.
Professor Prasad said, "Fitness trackers that track heart rates and steps are hot now, but wearable, non-invasive biosensors are good for disease management."
The general home blood glucose detector requires the user to take a little blood sample, usually by means of pinning the finger, and several times a day to be measured. And this new sensor made of fabric detects the amount of glucose in a small amount of perspiration on the skin.
"Our sensors work just like blood glucose strips and rely on the same chemical and enzymatic reactions," Prasad said. "But in our design we looked at watches, watches or skin-tight devices Near the amount of sweat less problem. "
Pradsad said researchers who study sweat often use a technique called iontophoresis that energizes the skin and gives the skin enough perspiration for testing. However, because this method may make the skin red and scalded, they must use other methods to detect small amounts of sweat.
The sweat used in their design is less than 1 microliters, which is equivalent to the liquid content of a salt crystal lattice.
This technology also provides real-time digital feedback.
Rujuta Munje, PhD student in Prasad and bioengineering, is the lead author of this article. They used a commercially available polymer fabric in blood glucose sensors and used cleanroom facilities to build the electronics in the device. The finished prototype is a compact, flexible rod-like device about 2.54 cm long.
"In our design we took advantage of the nature of the fabric itself and weaving," said Prasad. "Our innovation lies in the way we place the electrodes in the fabric and where we place them. In our way, a small amount of sweat also Can effectively spread to the surface of the entire device. "
Prasad said that the general blood glucose test strips also include a molecule that amplifies the chemical reaction signal, allowing the monitor to record electrical signals. However, if the instrument is worn against the skin, then the molecule may irritate the skin, which is another challenge to overcome.
Prasad and Munje changed the topography of the fabric surface in order to generate a strong enough signal to ensure a small amount of sweat.
"Our modification allows the material to bind glucose oxidase molecules that effectively amplify the glucose signal," said Prasad, "for the sake of its commercialization, and to make it available The process can not be complicated. "
Prasad and Munje can also use this device to explain a person's chemical changes in perspiration during the day.
"Glucose is a difficult molecule to monitor because there are other factors that can interfere with the signal," Prasad said. "Sweat pH, for example, or acidity can change dramatically due to the environment."
She notices that when people exercise or are stressed out, the levels of other compounds in their sweat, such as cortisol and lactate, change as well, which affects glucose testing.
"We've found that we can solve three key issues with our technology: a smaller amount of sweat, interference from other compounds, and fluctuations in pH," she said.
Prasad and Munje tested prototypes using volunteer sweat samples.
Although products made with this technology may not be available in the near future, this conceptual product was designed with the business and mass production factors in mind.
"At the moment, we plan to design it as a daily disposable product and we believe it can easily be integrated into existing consumer electronics platforms," ​​said Prasad. "We are likely to license this technology for marketing approval To very excited. "
Some researchers are still investigating whether glucose can be detected in other body fluids, such as urine and tears. If feasible, this will further reduce the need for invasive blood collection equipment. For example, Google is developing a smart contact lens, used to measure the tear in the glucose level.
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