Graphene Electronic Tattoos for Blood Pressure Monitoring

Bioengineers from Texas have developed graphene electronic tattoos, a new wearable device that continuously monitors the blood pressure of the user. It is based on electrical bioimpedance and leverages atomically thin, self-adhesive, lightweight, and unobtrusive electronic tattoos as human bioelectronic interfaces. The study was published in Nature Nanotechnology.

Maintaining healthy blood pressure is important for overall health. High blood pressure can result in serious complications if left unchecked. Continuous monitoring of arterial blood pressure (BP) in non-clinical (ambulatory) settings is very important to track numerous health conditions, including cardiovascular diseases. It is difficult to reliably and frequently measure blood pressure outside of a medical setting, as conventional blood pressure measures a single data point at a time. Various physiologic ambulatory BP monitoring devices are used to follow people outside of a medical setting. Besides their importance in medical diagnosis, ambulatory BP monitoring platforms can detect disease correlation with individual behavior, daily habits, and lifestyle, potentially enabling analysis of root causes, prognosis, and disease prevention. However, these devices are uncomfortable, bulky, intrusive, and incompatible with multiple daily activities.

Development of E-tattoo

Dmitry Kireev, The University of Texas at Austin, USA, and colleagues developed E-tattoo, a self-adhesive strip of graphene that contains bioimpedance sensors. The "tattoos" are placed over the radial and ulnar arteries, just above the wrist for hours. It provides uninterrupted blood pressure measurements at an accuracy level surpassing almost all available competing products present in the market. The graphene electronic tattoos are used to monitor arterial BP for >300 min, a period tenfold longer than reported in previous studies. Graphene is a hexagonal lattice of carbon atoms, just one atom thick. It is one of the thinnest and strongest materials.

To prove its efficiency, the device was used in seven healthy young adults, as they went through their day, including during exercises, such as push-ups, that stretched the skin underneath the sensors.

Key Observations

A key observation made during the study was that the device monitored arterial blood pressure for extended periods (longer than 300 minutes) with very high accuracy compared with a medical-grade device for continuously monitoring blood pressure.

The authors confirm that with e-tattoo the BP is recorded continuously and non-invasively, with an accuracy of 0.2 ± 4.5 mm Hg for diastolic pressures and 0.2 ± 5.8 mm Hg for systolic pressures, performance equivalent to Grade A classification. The e-tattoo enables blood pressure measurements in all types of situations: during periods of high stress, while sleeping, while exercising, etc. It can provide thousands of measurements more than any other device so far.

E-tattoo is one more successful step towards the development of technologies for continuously monitoring human physiology, with potential management and prevention of diseases.

Reference

Kireev, D., Sel, K., Ibrahim, B. et al. Continuous cuffless monitoring of arterial blood pressure via graphene bioimpedance tattoos. Nat. Nanotechnol. (2022). https://doi.org/10.1038/s41565-022-01145-w