Could also be printed directly on human skin for pulse monitoring
or as a human-machine interface --- imagine a computer mouse built into
your fingertip
May 26, 2017
Original link: http://www.kurzweilai.net/3d-printed-bionic-skin-could-give-robots-and-prosthetics-the-sense-of-touch
Schematic
of a new kind of 3D printer that can print touch sensors directly on a
model hand. (credit: Shuang-Zhuang Guo and Michael McAlpine/Advanced
Materials )
Engineering researchers at the University of Minnesota have developed a process for 3D-printing stretchable, flexible, and sensitive electronic sensory devices that could give robots or prosthetic hands — or even real skin — the ability to mechanically sense their environment.
One major use would be to give surgeons the ability to feel during minimally invasive surgeries instead of using cameras, or to increase the sensitivity of surgical robots. The process could also make it easier for robots to walk and interact with their environment.
Printing electronics directly on human skin could be used for pulse monitoring, energy harvesting (of movements), detection of finger motions (on a keyboard or other devices), or chemical sensing (for example, by soldiers in the field to detect dangerous chemicals or explosives). Or imagine a future computer mouse built into your fingertip, with haptic touch on any surface.
“While we haven’t printed on human skin yet, we were able to print on the curved surface of a model hand using our technique,” said Michael McAlpine, a University of Minnesota mechanical engineering associate professor and lead researcher on the study.* “We also interfaced a printed device with the skin and were surprised that the device was so sensitive that it could detect your pulse in real time.”
The researchers also visualize use in “bionic organs.”
A unique skin-compatible 3D-printing process
(left)
Schematic of the tactile sensor. (center) Top view. (right) Optical
image showing the conformally printed 3D tactile sensor on a fingertip.
Scale bar = 4 mm. (credit: Shuang-Zhuang Guo et al./Advanced Materials)
McAlpine and his team made the sensing fabric with a one-of-a kind 3D printer they built in the lab. The multifunctional printer has four nozzles to print the various specialized “inks” that make up the layers of the device — a base layer of silicone**, top and bottom electrodes made of a silver-based piezoresistive conducting ink, a coil-shaped pressure sensor, and a supporting layer that holds the top layer in place while it sets (later washed away in the final manufacturing process).
Surprisingly, all of the layers of “inks” used in the flexible sensors can set at room temperature. Conventional 3D printing using liquid plastic is too hot and too rigid to use on the skin. The sensors can stretch up to three times their original size.
The researchers say the next step is to move toward semiconductor inks and printing on a real surface. “The manufacturing is built right into the process, so it is ready to go now,” McAlpine said.
The research was published online in the journal Advanced Materials. It was funded by the National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health.
* McAlpine integrated electronics and novel 3D-printed nanomaterials to create a “bionic ear” in 2013.
** The silicone rubber has a low modulus of elasticity of 150 kPa, similar to that of skin, and lower hardness (Shore A 10) than that of human skin, according to the Advanced Materials paper.
College of Science and Engineering, UMN | 3D Printed Stretchable Tactile Sensors
