An assistant professor at The University of Texas at Austin‘s Department of Aerospace Engineering and Engineering Mechanics Cockrell School of Engineering is in the forefront of research to develop “electronic tattoos,” which are not a new, high-tech form of body art, but a potentially revolutionary advance in the technology of medical monitoring devices.
Dr. Nanshu Lu’s vision is that through development of novel bio-integrated soft electronics for cardiac, neural and epidermal applications, patients with heart disease to no longer be cumbered with brick-size Holter monitors fastened to their arms or waists, with attendant webs of electrodes connected to their chests to monitor their heart condition, and for those unable to speak to be enabled to communicate by muscle movements in their throats, and for blind individuals to will with finger tubes that “stimulate their fingertips with programmable electrotactile stimulations in place of bulky, old-school braille.
These hoped-for advances will be thanks to a developing technology called “bio-integrated electronics,” or “electronic tattoos.” Dr. Lu is part of the research team at the $18.5 million, National Science Foundation funded, NASCENT engineering research center, located at UT Austin. Her particular research interest is on the mechanics of flexible electronics in all aspects such as materials, structural design, micro-fabrication, mechanical tests, bio-integration as well as analytical and numerical mechanics modeling. Dr. Lu’s representative work includes highly stretchable metal thin films supported by polymer substrates, instrumented balloon catheters for minimally invasive surgeries, and tattoo-like epidermal electronics, and at NACENT she will apply her expertise in stretchable metal and silicon to emerging two-dimensional materials such as graphene. Her research group works in close collaboration with faculty in electrical, biomedical and chemical engineering, both domestically and internationally, on development of next-generation flexible/stretchable electronics, photonics and therapeutics.
“This technology could help electronics that interact with humans be more mechanically compatible,” Dr. Lu commented to UT science writer Elena Watts. “In terms of application, its uses range from consumer products like rollable displays and solar cells, to personal digital health care like EKG and emotion sensors, to computer gaming.”
Dr. Nanshu Lu joined the Department of Aerospace Engineering and Engineering Mechanics at The University of Texas at Austin as an Assistant Professor in fall 2011. She received her bachelor’s degree in Solid Mechanics from the Department of Engineering Mechanics at Tsinghua University, Beijing in 2005, and obtained her Ph.D. in Mechanics of Materials from Harvard University working with Professors Zhigang Suo and Joost Vlassak in 2009. She then received a Beckman Postdoctoral Fellowship and became a postdoctoral researcher at the University of Illinois at Urbana-Champaign, where she was mentored by Professor John Rogers, one of the world’s leading researchers in the field of flexible electronics. Dr. Lu’s interest in development of electronic tattoos began when Dr. Rogers challenged her and other young postdoctoral fellows by presenting his forearm and squeezing a temporary tattoo, bending and folding the image into the creases of his skin, and asking them to create electronics with the same properties.
In the spring of 2010, Dr. Lu and her lab colleagues began working day and night on tattoo technology, researching properties of human skin, biocompatible materials, and structural designs of soft circuits, and finally determining that silicon is the optimal choice of semiconductors due to its speed, reliability and well-established manufacturing process. The stiff silicon wafer, ubiquitous in the integrated circuit industry, became bendable by thinning it to nanometers — solid state for “flexible state” if you will — analogous to the way rigid and brittle window glass cam be spun into thin, flexible, glass fiber.
Ms. Watts’ report notes that while two strategies of stretchable electronics already existed — wrinkled silicon ribbons and interconnected silicon islands — neither could offer the sufficient conformity and softness as the temporary transfer tattoo, and to achieve the necessary intimacy between the sensor and skin, Dr. Lu disposed of the squared island convention and instead cut the silicon into the sinuous shapes of metal bridges that linked them, inventing a geometrical configuration that rotated and twisted to allow stretch or compression of the soft circuit board.
The next challenge was to devise a means of applying the soft, droopy material to the skin, and the stiff plastic that transports temporary body art tattoos inspired Dr. Lu’s conceptualization of a water-soluble version with which when the plastic dissolved, the soft, thin residual patch would seek the skin as support. When appropriate, a temporary tattoo applied with a bioadhesive activated by body temperature could camouflage the electronics.
Dr. Lu’s particular area of expertise — the interface of flexible electronics with biosystems — is one of three areas crucial to the development of bio-integrated electronics. The other two: wireless data transmission, and wireless power transmission, are also key areas of research and development toward the objective of enabling electronic tattoos to become practical for everyday use. “The long-term integration of electronics with organisms will open a new era for health monitoring,” Dr. Lu affirms.
Four doctoral students and five undergraduate students currently comprise the Lu Research Group, whose research focus is to investigate the mechanics and materials of bio-integrated soft electronics with the ultimate goal ito help develop high-quality, multifunctional flexible electronics in forms that can conform with the soft, curvilinear and time-dynamic surfaces of the human body for sensing, stimulation and energy harvesting. A main focus of Dr. Lu’s lab is to train the next generation of scientists through forming a diversified group conducive to learning and carrying out multidisciplinary research. The Lu Lab has just received NSF funding and is now actively investigating the mechanical interactions at bioelectronics interfaces with a particular focus on transdermal electronics, where a piece of electronic tattoo will be able to access subcutaneous signals or deliver subcutaneous treatment.
In recognition of her work in bio-integrated flexible electronics, Dr. Lu in February received a Grand Prix award at the Netexplo Forum in Paris, France, which focuses on the practical application of digital inventions that revolutionize lives. Dr. Lu’s project was selected from 1,500 nominations for the Grand Prix.
She was also honored last year, along with her University of Texas at Austin Cockrell School of Engineering colleague assistant professor in the Department of Electrical and Computer Engineering Zheng Wang, by the MIT Technology Review, which named her one of the world’s top 35 innovators under the age of 35. A panel of experts and Technology Review editorial staffers chose Dr. Lu from among pool of 250 nominees for the global list, which highlights young innovators who are changing the world. Facebook’s Mark Zuckerberg was a winner in 2007. Lu, Wang and the other TR35 2012 winners were featured in the September/October, 2012 issue of Technology Review and online.
“Nanshu’s work could have a major impact on medical procedures,” Philip Varghese, chair of the UT Austin Department of Aerospace Engineering and Engineering Mechanics commented in a release. “She combines expertise in theoretical mechanics with strong experimental skills, and applies her knowledge to a variety of challenging problems, including biointegrated electronics.”
“Nanshu’s work is very exciting since the field of bio-integrated electronics shows promise for fundamentally changing how medical devices interact with the human body,” Dr. Noel Clemens, chair of the Aerospace Engineering and Engineering Mechanics Department, is cited commenting. “While Nanshu does groundbreaking research, she is also a dedicated teacher who shows a strong commitment to her students. We are proud to have such an exceptional individual in our department.”
Dr. Lu’s research has been highlighted by news media such as Nature News”, “ScienceNOW”, “Technology Review”, “Chemical & Engineering News”, and many other periodicals and journals.