This year has already seen massive heat waves around the globe, with cities in Mexico, India, Pakistan and Oman hitting temperatures near or past 50 degrees Celsius (122 degrees Fahrenheit).

As global temperatures and urban populations rise, the world’s cities have become “urban heat islands,” with tight-packed conditions and thermal radiation emitting from pavement and skyscrapers trapping and magnifying these temperatures. With 68% of all people predicted to live in cities by 2050, this is a growing, deadly problem.

In a paper publishedin Science, researchers from the UChicago Pritzker School of Molecular Engineering (PME) detail a new wearable fabric that can help urban residents survive the worst impacts of massive heat caused by global climate change, with applications in clothing, building and car design, and food storage.

In tests under the Arizona sun, the material kept 2.3 degrees Celsius (4.1 degrees Fahrenheit) cooler than the broadband emitter fabric used for outdoor endurance sports and 8.9 degrees Celsius (16 degrees Fahrenheit) cooler than the commercialized silk commonly used for shirts, dresses and other summer clothing.

This, the team hopes, will help many avoid the heat-related hospitalizations and deaths seen in global population centers this year alone.

“We need to reduce carbon emission and make our cities carbon negative or carbon neutral,” PME Asst. Prof. Po-Chun Hsu said. “But meanwhile, people are feeling the impact of these high temperatures.”

‘You have to consider the environment’

Existing cooling fabric for outdoor sports works by reflecting the sun’s light in a diffuse pattern so it doesn’t blind onlookers. But in an urban heat island, the sun is only one source of heat. While the sun bakes from above, thermal radiation emitted from buildings and pavement blast city-dwellers with blistering heat from the sides and below.

This means many materials that perform well in lab tests won’t help city-dwellers in Arizona, Nevada, California, Southeast Asia and China when predicted massive heat waves hit them over the next few weeks.

“People normally focus on the performance or the material design of cooling textiles,” said co-first author Ronghui Wu, a postdoctoral researcher at PME. “To make a textile that has the potential to apply to real life, you have to consider the environment.”

One simple example of considering the environment is that people stand. They are wearing materials designed to reflect direct sunlight, but only their hats, shoulder coverings and the tops of their shoes—about 3% of their clothing—face that direct light. The other 97% of their clothes are being heated by the thermal radiation coming at them from the sides and below, which broadband emitter fabric does not fight.

The sun and sidewalk cook with different heats. Creating one material capable of protecting wearers from both provided a major engineering challenge for the team.

“Solar is visible light, thermal radiation is infrared, so they have different wavelengths. That means you need to have a material that has two optical properties at the same time. That’s very challenging to do,” said co-first author Chenxi Sui, a Ph.D. candidate at PME. “You need to play with material science to engineer and tune the material to give you different resonances at different wavelengths.”

The costs of comfort

Cooling a home too often means warming the planet, with the carbon impact of air conditioning and refrigeration systems contributing to climate change.

“Our civilization actually uses about 10 to 15% of the energy in total just to make ourselves feel comfortable wherever we go,” Hsu said.

The risk from heat is not distributed evenly, however. In the U.S. and Japan, more than 90% of households have an air conditioner, a number that drops to 5% in India and parts of Africa.

The PME team’s new textile, which has received a provisional patent, can help provide a passive cooling system that can supplement and reduce the need for energy- and cost-intensive systems.

The applications go far beyond clothing.

A thicker version of the fabric protected by an invisible layer of polyethylene could be used on the sides of buildings or cars, lowering internal temperatures and reducing the cost and carbon impact of air conditioning. Similarly, the material could be used to transport and store milk and other foods that would otherwise spoil in the heat, cutting refrigeration’s impact.

“You can save a lot of cooling, electricity and energy costs because this is a passive process,” Sui said.

Imagine finding your location without GPS. Now apply this to tracking an item in the body. This has been the challenge with tracking “smart” pills—pills equipped with smart sensors–once swallowed. At the USC Viterbi School of Engineering, innovations in wearable electronics and AI have led to the development of ingestible sensors that not only detect stomach gases but also provide real-time location tracking.

Developed by the Khan Lab, these capsules are tailored to identify gases associated with gastritis and gastric cancers. The research, to be published in Cell Reports Physical Science, shows how these smart pills have been accurately monitored through a newly designed wearable system. This breakthrough represents a significant step forward in ingestible technology, which Yasser Khan, an Assistant Professor of Electrical and Computer Engineering at USC, believes could someday serve as a “Fitbit for the gut” and for early disease detection.

While wearables with sensors hold a lot of promise to track body functions, the ability to track ingestible devices within the body has been limited. However, with innovations in materials, the miniaturization of electronics, as well as new protocols developed by Khan, researchers have demonstrated the ability to track the location of devices specifically in the GI tract.

Khan’s team with the USC Institute for Technology and Medical Systems Innovation (ITEMS) at the Michelson Center for Convergent Biosciences, placed a wearable coil that generates a magnetic field on a t-shirt. This field, coupled with a trained neural network, allows his team to locate the capsule within the body. According to Ansa Abdigazy, lead author of the work and a Ph.D. student in the Khan Lab, this has not been demonstrated with a wearable before.

The second innovation within this device is the newly created “sensing” material. Capsules are outfitted not just with electronics for tracking location but with “optical sensing membrane that is selective to gases.” This membrane is comprised of materials whose electrons change their behavior within the presence of ammonia gas.

Ammonia—is a component of H pylori—gut bacteria that, when elevated, could be a signal of peptic ulcer, gastric cancer, or irritable bowel syndrome. Thus, says Khan, “The presence of this gas is a proxy and can be used as an early disease detection mechanism.”

The USC team has tested this ingestible device in many different environments including liquid environments and simulating a bovine intestine. “The ingestible system with the wearable coil is both compact and practical, offering a clear path for application in human health,” says Khan. The device is currently patent pending and the next step is to test these wearables with swine models.

Beyond the use of this device for early detection of peptic ulcers, gastritis, and gastric cancers, there is potential to monitor brain health. How? Because of the brain-gut axis. Neurotransmitters reside in the gut and “how they’re upregulated and downregulated have a correlation to neurodegenerative diseases,” says Khan.

This focus on the brain is the ultimate goal of Khan’s research. He is interested in developing non-invasive ways to detect neurotransmitters related to Parkinson’s and Alzheimer’s.