Power/Performance Bits: Jan. 18

3D printed custom wearables
Researchers from the University of Arizona created a 3D printed wearable that can operate continuously through wireless power to track body temperature and muscle deformation during exercise.

Based on 3D body scans of the wearer, the medical-grade ‘biosymbiotic device’ can be custom printed to conform to a user’s skin without the need for adhesives, which can irritate the skin or come loose with regular wear.

“We introduce a completely new concept of tailoring a device directly to a person and using wireless power casting to allow the device to operate 24/7 without ever needing to recharge,” said Philipp Gutruf, assistant professor of biomedical engineering at University of Arizona.

The custom printed device can be created as a lightweight, breathable, mesh cuff designed specifically for the bicep, calf, or torso, enabling it to gather certain information more precisely than wrist-worn smartwatches, the team said.

University of Arizona engineers have developed a way to 3D-print medical-grade wearable devices, such as this one, based on body scans of the wearer. (Credit: Philipp Gutruf/College of Engineering)

“If you want something close to core body temperature continuously, for example, you’d want to place the sensor in the armpit. Or, if you want to measure the way your bicep deforms during exercise, we can place a sensor in the devices that can accomplish that,” said Tucker Stuart, a doctoral student in biomedical engineering at University of Arizona. “Because of the way we fabricate the device and attach it to the body, we’re able to use it to gather data a traditional, wrist-mounted wearable device wouldn’t be able to collect.”

They tested the devices ability to monitor parameters including temperature and strain while a person jumped, walked on a treadmill, and used a rowing machine, sometimes using multiple devices at once to track exercise intensity and the way muscles deformed with fine detail.

The device can receive power from a wireless system within a range of several meters, and it also includes a small energy storage unit for when the wearer goes outside that range.

“These devices are designed to require no interaction with the wearer,” Gutruf said. “It’s as simple as putting the device on. Then you forget about it, and it does its job.”

Long-term digital storage with dyes
Researchers from Harvard University and Northwestern University propose a way to store digital data for a long period of time using fluorescent inks.

The approach uses mixtures of seven commercially available fluorescent dyes to save data files. The dyes are dropped by an inkjet printer and read with a microscope that can detect the different wavelengths of light each dye emits. The binary contents can then be decoded.

The method could save data for thousands of years, the researchers noted, while consuming no power once the data is recorded. Because reading the information back requires a specialized microscope, and because it isn’t connected to the Internet, there’s also a certain amount of security.

“This method could provide access to archival data storage at a low cost,” said Amit A. Nagarkar, who conducted the research as a postdoctoral fellow at Harvard. “[It] provides access to long-term data storage using existing commercial technologies — inkjet printing and fluorescence microscopy.”

The team thinks it could be useful for information that must be retained for regulatory reasons, such as legal and financial records, as well as satellite data where long-term storage is necessary.

The dye molecules are dropped onto an epoxy surface to which they chemically bond, locking information in place.

Each number, letter, and pixel in the data they want to store is represented in ASCII by a group of ones and zeros, depending on whether a particular dye is absent (0) or present (1). The researchers reported that the information can be read with 99.6 percent accuracy, and in a 7.2-by-7.2 millimeter surface they were able to write 1,407,542 bytes of digital information with the dyes.

In a demonstration, they wrote and retrieved a paper by and JPEG image of physicist and chemist Michael Faraday. The system was able to write information at an average rate of 128 bits per second and read it at a rate of 469 bits/s, which the team believes is the fastest reported read speed of any molecular information storage method thus far. The fluorescent data could be read 1,000 times without a significant loss in intensity.

The technology has been licensed to a company started by the researchers to develop into a commercial product.