Engineers have demonstrated that the simple combination of pencils and paper could be used to create devices that might be used to monitor personal health. 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.
The conventional approach for developing an on-skin biomedical electronic device is usually complex and often expensive to produce. The new approach is low-cost and simple — it can be made using widely available pencils and paper.
The team 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 also could be applied to the paper to help it stick better to a person's skin.
The discovery could have broad future applications in home-based, personalized healthcare, education, and remote scientific research such as during the COVID-19 pandemic. The next step would be to further develop and test the use of the biomedical components including electrophysiological, temperature, and biochemical sensors.
If someone has a sleep issue, for example, they could draw a biomedical device that could help monitor their sleep levels. 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 this approach is that paper can decompose in about a week, compared to many commercial devices that contain components that are not easily broken down.