Saying one thing while feeling another is a normal part of being human—but consistently hiding emotions can lead to serious psychological consequences like anxiety or panic attacks. To help healthcare providers better detect these hidden emotions, researchers led by a team at Penn State have developed a soft, stretchable, rechargeable sticker that can detect genuine emotional states by measuring physiological signals such as skin temperature, heart rate, and more—even when someone is putting on a brave face.
This innovative wearable patch was recently detailed in a study published in Nano Letters. It’s capable of simultaneously and accurately monitoring multiple emotional indicators in real time.
“This is a new and improved way to understand our emotions by looking at multiple body signals at once,” said Huanyu “Larry” Cheng, lead author of the study and the James L. Henderson, Jr. Memorial Associate Professor of Engineering Science and Mechanics at Penn State. “Relying only on facial expressions to understand emotions can be misleading. People often don’t visibly show how they truly feel, so that’s why we’re combining facial analysis with other key physiological signals. This can lead to better mental health monitoring and support.”
The patch tracks a variety of physical responses that are closely tied to emotional states—including skin temperature, humidity, heart rate, and blood oxygen levels. What makes the device especially powerful is that its sensors operate independently, meaning each measurement remains accurate without interference from the others.
By integrating this physiological data with facial expression recognition, the patch can distinguish between authentic emotions and those that are masked or performed. The data is transmitted wirelessly to mobile devices or the cloud, offering clinicians a way to assess emotional well-being remotely. Notably, the patch only collects non-identifying physiological signals—preserving personal privacy by design.
“This technology has the potential to support people who are struggling with their mental health but may not be fully honest with others—or even themselves—about the extent of their distress,” said Yangbo Yuan, co-author of the paper and a doctoral student in engineering science and mechanics at Penn State.
Cheng added that the data collected by the patch could help bridge cultural or social differences in emotional expression, helping healthcare providers better understand patients who may appear more stoic or outwardly composed.
The team designed the Band-Aid-sized device using layers of flexible metals like platinum and gold, shaped into wave-like patterns that retain sensitivity even when the patch is bent or stretched. The materials inside the patch include components that respond to temperature changes and carbon-based tubes that absorb moisture to monitor humidity.
Special care was taken to ensure the sensors do not interfere with each other: for example, a rigid backing layer shields temperature and humidity sensors from facial movements, while waterproof materials prevent moisture from affecting certain readings.
“We’ve engineered this device to measure different signals independently, without cross-interference, which provides a much clearer and more accurate picture of what’s happening beneath the surface,” said Libo Gao, co-corresponding author and associate professor at Xiamen University.
By Impact Lab
