Additively fabricated on-skin sensors for mechanical and thermal biosignal monitoring

Continuous biosignal monitoring with on-skin worn sensor devices enables out-of-hospital patient monitoring (i.e. ubiquitous healthcare), which has high potential to reduce various disease-related societal costs through large-scale screening of disease risk groups. However, novel fabrication methods need to be adopted to enable the required large-scale deployment of such devices. Additive fabrication technologies have emerged as potential candidates to meet this challenge due to their low material consumption, scalability, and compatibility with skin-conformable low T_g polymeric substrates. This review article discusses recent advances in additively fabricated on-skin biosignal sensors and focuses on the following topics: (1) available additive fabrication technologies; (2) on-skin measurable mechanical and thermal biosignals and related additively fabricated biosignal sensors; and (3) the emerging field of printed electronic tattoo (e-tattoo)-type mechanical and thermal biosignal sensors.