-
- News
- Books
Featured Books
- pcb007 Magazine
Latest Issues
Current IssueThe Hole Truth: Via Integrity in an HDI World
From the drilled hole to registration across multiple sequential lamination cycles, to the quality of your copper plating, via reliability in an HDI world is becoming an ever-greater challenge. This month we look at “The Hole Truth,” from creating the “perfect” via to how you can assure via quality and reliability, the first time, every time.
In Pursuit of Perfection: Defect Reduction
For bare PCB board fabrication, defect reduction is a critical aspect of a company's bottom line profitability. In this issue, we examine how imaging, etching, and plating processes can provide information and insight into reducing defects and increasing yields.
Voices of the Industry
We take the pulse of the PCB industry by sharing insights from leading fabricators and suppliers in this month's issue. We've gathered their thoughts on the new U.S. administration, spending, the war in Ukraine, and their most pressing needs. It’s an eye-opening and enlightening look behind the curtain.
- Articles
- Columns
- Links
- Media kit
||| MENU - pcb007 Magazine
Sweat Sensor Detects Stress Levels; May Find Use in Space Exploration
March 9, 2020 | IDTechExEstimated reading time: 3 minutes

If someone asked you right now how stressed you are, what would you say? A little? A lot? You do not know?
Those are all valid responses, but they are not especially useful to researchers and medical professionals because they are subjective and not easily quantified. Nonetheless, in lieu of a better method of measuring stress, the common method for years has consisted of a stress questionnaire. The main alternative to the questionnaire, a blood test, can provide quantitative data but requires a trained professional to draw the blood, and the stress of the procedure itself—being poked with a large needle—can skew the results of a lot of people.
But something better might be right around the corner.
Wei Gao, assistant professor of medical engineering at Caltech, has produced a wireless sweat sensor that can accurately detect levels of cortisol, a natural compound that is commonly thought of as the body's stress hormone. In a new paper appearing in the journal Matter, Gao and his fellow researchers show how they designed and made the mass-producible device and how it works, and demonstrate that it is effective at detecting cortisol levels in near real time.
The development of an inexpensive and accurate device for measuring cortisol could allow for more widespread and easier monitoring of stress but also of other conditions including anxiety, post-traumatic stress disorder, and depression—all of which are correlated with changes in cortisol levels.
The sensor Gao developed is prepared using a similar approach as another sweat sensor he recently created that can measure the level of uric acid in the bloodstream, which is useful for monitoring conditions like cardiovascular disease, diabetes, or kidney disease. That sweat sensor, and the new one Gao and his team have created, are both made of graphene, a sheet-like form of carbon. A plastic sheet is etched with a laser to generate a 3D graphene structure with tiny pores in which sweat can be analyzed. Those pores create a large amount of surface area in the sensor, which makes it sensitive enough to detect compounds that are only present in very small amounts in sweat. In the new sensor, those tiny pores are coupled with an antibody, a type of immune system molecule, specifically sensitive to cortisol, thus allowing it to detect the compound.
The sensor was tested in two different ways. In one test, a volunteer's sweat was analyzed over a period of six days, and data representing cortisol levels were collected. In a healthy individual, cortisol levels rise and fall on a daily cycle. The levels peak just after an individual wakes up each morning and decline throughout the day, and that is exactly what the sensor detected.
Gao says this is the first demonstration of a sensor that can noninvasively monitor the daily fluctuation of cortisol, adding that monitoring the daily cortisol cycle of a patient could reveal the presence of mental health conditions.
"Depression patients have a different circadian pattern of cortisol than healthy individuals do," he says. "With PTSD patients, it's another different one."
In the other test, changes in cortisol levels were recorded as they occurred in response to an acute stressor. This was done through two experiments. In the first, test subjects were asked to perform aerobic exercises, because intense exercise is known to cause a strong increase in cortisol. In the second experiment, test subjects were asked to submerge their hands in ice water, a stressor sufficient to elicit cortisol release. In both experiments, the sensors detected rising cortisol levels right away.
"Our analysis time could be only a few minutes," Gao says. "Typically, a blood test takes at least one to two hours and requires stress-inducing blood draw. For stress monitoring, time is very important."
Though Gao's sensor may find many uses in typical medical applications here on Earth, it is also being vetted for potential off-world applications. In October, NASA announced that Gao is one of six researchers selected to participate in studies of the health of humans on deep-space missions. Gao will receive funding to develop the sensor technology into a system for monitoring the stress and anxiety of astronauts as part of the program, which is being administered by the Translational Research Institute for Space Health (TRISH).
"We aim to develop a wearable system that can collect multimodal data, including both vital sign and molecular biomarker information, to obtain the accurate classification for deep space stress and anxiety," Gao says.
News courtesy of IDTechEx and Caltech.
Suggested Items
Meet the Author Podcast: Martyn Gaudion Unpacks the Secrets of High-Speed PCB Design
07/10/2025 | I-Connect007In this special Meet the Author episode of the On the Line with… podcast, Nolan Johnson sits down with Martyn Gaudion, signal integrity expert, managing director of Polar Instruments, and three-time author in I-Connect007’s popular The Printed Circuit Designer’s Guide to... series.
TTCI Joins Printed Circuit Engineering Association to Strengthen Design-to-Test Collaboration and Workforce Development
07/09/2025 | The Test Connection Inc.The Test Connection Inc. (TTCI), a leading provider of electronic test and manufacturing solutions, is proud to announce its membership in the Printed Circuit Engineering Association (PCEA), further expanding the company’s efforts to support cross-functional collaboration, industry standards, and technical education in the printed circuit design and manufacturing community.
Study on Resonance Mitigation in Metallic Shielding for Integrated Circuits
07/08/2025 | Maria Cuesta-Martin, Victor Martinez, Vidal Gonzalez Aguado, Würth ElektronikInherent cavity resonant modes often lead to significant degradation of shielding effectiveness, responsible for unwanted electromagnetic coupling. Cavity resonant modes of the metal shielding enclosure can produce two adverse problems: the mutual coupling among different RF modules and shielding effectiveness reduction of the metal enclosure. The cabinets serve to shield certain components from electromagnetic interference (EMI). However, these cavities present some resonance peaks at 5 GHz, making it impossible to use them at higher frequencies.
The Global Electronics Association Releases IPC-8911: First-Ever Conductive Yarn Standard for E-Textile Application
07/02/2025 | Global Electronics AssociationThe Global Electronics Association announces the release of IPC-8911, Requirements for Conductive Yarns for E-Textiles Applications. This first-of-its-kind global standard establishes a clear framework for classifying, designating, and qualifying conductive yarns—helping to address longstanding challenges in supply chain communication, product testing, and material selection within the growing e-textiles industry.
Magnalytix and Foresite to Host Technical Webinar on SIR Testing and Functional Reliability
06/26/2025 | MAGNALYTIXMagnalytix, in collaboration with Foresite Inc., is pleased to announce an upcoming one-hour Webinar Workshop titled “Comparing SIR IPC B-52 to Umpire 41 Functional & SIR Test Method.” This session will be held on July 24, 2025, and is open to professionals in electronics manufacturing, reliability engineering, and process development seeking insights into new testing standards for climatic reliability.