Researchers Use Pencil to Draw Bioelectronic Devices on Human Skin
Scientists from the University of Missouri, the University of Illinois and Yale University have demonstrated that a combination of pencils and paper could be used to create on-skin bioelectronic devices that might be used to monitor personal health. They’ve fabricated and evaluated a rich variety of pencil-paper-based bioelectronic devices, ranging from biophysical sensors and sweat biochemical sensors to thermal stimulators, ambient humidity energy harvesters, and transdermal drug-delivery systems.
Conceptual illustrations of drawing on-skin electronics on paper using a 9B sketching pencil. Image credit: Xu et al, doi: 10.1073/pnas.2008422117.
“Many existing commercial on-skin biomedical devices often contain two major components — a biomedical tracking component and a surrounding flexible material, such as plastic, to provide a supportive structure for the component to maintain an on-skin connection with a person’s body,” said senior author Dr. Zheng Yan, a researcher in the Department of Biomedical, Biological Chemical Engineering and the Department of Mechanical Aerospace Engineering at the University of Missouri.
“The conventional approach for developing an on-skin biomedical electronic device is usually complex and often expensive to produce.”
“In contrast, our approach is low-cost and very simple. We can make a similar device using widely available pencils and paper.”
In the study, Dr. Yan and colleagues discovered that pencils containing more than 90% graphite are able to conduct a high amount of energy created from the friction between paper and pencil caused by drawing or writing.
Specifically, they found pencils with 93% graphite were the best for creating a variety of on-skin bioelectronic devices drawn on commercial office copy paper.
“A biocompatible spray-on adhesive could also be applied to the paper to help it stick better to a person’s skin,” Dr. Yan said.
The discovery could have broad future applications in home-based, personalized health care, education and remote scientific research.
The team’s next step would be to further develop and test the use of the biomedical components, including electrophysiological, temperature and biochemical sensors.
“For example, if a person has a sleep issue, we could draw a biomedical device that could help monitor that person’s sleep levels,” Dr. Yan said.
“Or in the classroom, a teacher could engage students by incorporating the creation of a wearable device using pencils and paper into a lesson plan.”
“Furthermore, this low-cost, easily customizable approach could allow scientists to conduct research at home, such as during a pandemic.”
“An additional benefit to our approach is that paper can decompose in about a week, compared to many commercial devices that contain components that are not easily broken down.”
The team’s paper was published in the Proceedings of the National Academy of Sciences.
_____
Yadong Xu et al. Pencil-paper on-skin electronics. PNAS, published online July 13, 2020; doi: 10.1073/pnas.2008422117
