A team of researchers has developed a tiny sensor that can detect lithium levels—that is needed in the right quantity to manage mental health disorders like bipolar disorder and depression— from sweat on the surface of a fingertip in as little as 30 seconds, without a trip to the clinic.
Presently, patients must undergo invasive blood tests to precisely monitor the amount of this medication in the body. Lithium can alleviate the symptoms of bipolar disorder and depression — if taken in just the right amount. Too little won’t work, while too much can bring on dangerous side effects.
The researchers will present their results today at the fall meeting of the American Chemical Society (ACS) to be held in a hybrid mode from August 21–25. Not only must lithium be taken at a certain dosage, but patients often struggle to take it as prescribed and may miss pills.
So, when the medication doesn’t appear to be working, health care providers need to know how much medication the patient is actually swallowing. But current options for monitoring have significant drawbacks.
For example, blood draws produce accurate results, but they are invasive and time consuming. Pill counters, meanwhile, don’t directly measure the intake of the medication. To address these limitations, the team turned to another body fluid. “Although it may not be visible, the human body constantly produces sweat, often only in very small amounts,” said Shuyu Lin, a researcher who is co-presenting the work with graduate student Jialun Zhu at the meeting.
“Small molecules derived from medication, including lithium, show up in that sweat. We recognized this as an opportunity to develop a new type of sensor that would detect these molecules.”
“Through a single touch, our new device can obtain clinically useful molecular-level information about what is circulating in the body,” said Sam Emaminejad, the project’s principal investigator, who is at the University of California, Los Angeles (UCLA).
“We already interact with a lot of touch-based electronics, such as smartphones and keyboards, so this sensor could integrate seamlessly into daily life.”
Devising a sensor to detect lithium presented some technical challenges, however. Sweat is generally only present in minute amounts, but the electrochemical sensing needed to detect charged particles of lithium requires an aqueous, or watery, environment.
The sensor is still in the preliminary testing phase, but ultimately, the researchers envision incorporating it into a larger, yet-to-be-designed system that provides visual feedback to provider or the patient.