Printing Flexible and Hybrid Electronics for Human Skin and Eye‐Interfaced Health Monitoring Systems

Advances in printing materials and techniques for flexible and hybrid electronics in the domain of connected healthcare have enabled rapid development of innovative body‐interfaced health monitoring systems at a tremendous pace. Thin, flexible, and stretchable biosensors that are printed on a biocompatible soft substrate provide the ability to noninvasively and unobtrusively integrate with the human body for continuous monitoring and early detection of diseases and other conditions affecting health and well being. Hybrid integration of such biosensors with extremely well‐established silicon‐based microcircuit chips offers a viable route for in‐sensor data processing and wireless transmission in many medical and clinical settings. Here, a set of advanced and hybrid printing techniques is summarized, covering diverse aspects ranging from active electronic materials to process capability, for their use in human skin and eye‐interfaced health monitoring systems with different levels of complexity. Essential components of the devices, including constituent biomaterials, structural layouts, assembly methods, and power and data processing configurations, are outlined and discussed in a categorized manner tailored to specific clinical needs. Perspectives on the benefits and challenges of these systems in basic and applied biomedical research are presented and discussed. Mechanically flexible health monitoring systems that are capable of detecting important biosignals and biomarkers from the skin and eye(s) are making remarkable progress and maturing to nearly consumer level by virtue of significant advances in flexible materials and hybrid printing techniques. Various classes of flexible and hybrid electronics in the domain of connected healthcare are outlined in a categorized manner, tailored to specific clinical needs.