Custom-Built ATmega328-Based Smartwatch Tracks Acetaminophen Absorption by Analyzing Sweat
The custom-built smartwatch uses a small electric current to force the wearer's wrist to sweat, then tracks their medication levels.
Engineers from the UCLA Samueli School of Engineering and the Stanford School of Medicine have developed a smartwatch capable of tracking the wearer's metabolization of medicines — by analyzing their sweat.
"We wanted to create a wearable technology that can track the profile of medication inside the body continuously and non-invasively," explains study lead Assistant Professor Sam Emaminejad. 2This way, we can tailor the optimal dosage and timing of the intake for each individual. And using this personalization approach, we can improve the efficacy of the therapeutic treatments."
"This technology is a game-changer and a significant step forward for realizing personalized medicine,” adds co-author Professor Ronald W. Davis. "Emerging pharmacogenomic solutions, which allow us to select drugs based on the genetic makeup of individuals, have already shown to be useful in improving the efficacy of treatments. So, in combination with our wearable solution, which helps us to optimize the drug dosages for each individual, we can now truly personalize our approaches to pharmacotherapy."
The system works by taking advantage of the small molecular size of many drugs, which mean they are incorporated into sweat in quantities not only analyzable but which reflect how much of the drug is still circulating in the wearer's system. To prove the concept, the watch was used to track acetaminophen — an over-the-counter painkiller — over a short period, using a small electric current to force the wearer to sweat under the sensor.
The custom watch includes both an on-board LCD panel for live monitoring and a Bluetooth connection for transmission to an external data capture system for later analysis. All were driven by a Microchip ATmega328-based microcontroller linked to a 16-bit Texas Instrument DAC8552 digital-to-analog converter, a Linear Technology LT1462 transfer impedance amplifier, and a TI 12-bit ADS1015 analog-to-digital converter, with a Wurth Electronik AMB2621 Bluetooth module used for communication.
The full study has been published under closed-access terms in the Proceedings of the National Academy of Sciences (PNAS).