The group of Tianling REN at the school of information science and technology of Tsinghua University has developed a graphen-based electronic tattoo which can be used for detecting multiple functions such as breathing, heart rate, sleep analysis and vocalization. The team applied graphene oxide by wet stripping and reduced it to graphene by laser irradiation, resulting in an ultra-thin layer which could be personalized as a tattoo during the irradiation process. The graphene layers respond to the stretching and compression of the skin surface resulting in changes of electric resistance for readout devices. In addition to skin, graphene tattoo were transferred to other substrates such as leaves, and silk.

Tsinghua University news release, July 31, 2018