Battery-free, stretchable optoelectronic systems for wireless optical characterization of the skin

Abstract

Recent advances in materials, mechanics, and electronic device design are rapidly establishing the foundationsfor health monitoring technologies that have“skin-like”properties, with options in chronic (weeks) integrationwith the epidermis. The resulting capabilities in physiological sensing greatly exceed those possible withconventional hard electronic systems, such as those found in wrist-mounted wearables, because of the intimateskin interface. However, most examples of such emergingclasses of devices require batteries and/or hard-wiredconnections to enable operation. The work reported here introduces active optoelectronic systems that functionwithout batteries and in an entirely wireless mode, with examples in thin, stretchable platforms designed formultiwavelength optical characterization of the skin. Magnetic inductive coupling and near-field communication(NFC) schemes deliver power to multicolored light-emitting diodes and extract digital data from integratedphotodetectors in ways that are compatible with standard NFC-enabled platforms, such as smartphones andtablet computers. Examples in the monitoring of heart rate and temporal dynamics of arterial blood flow, inquantifying tissue oxygenation and ultraviolet dosimetry, and in performing four-color spectroscopic evaluation ofthe skin demonstrate the versatility of these concepts. The results have potential relevance in both hospitalcare and at-home diagnostics.