3D multifunctional integumentary membranes for spatiotemporal cardiac measurements and stimulation across the entire epicardium

Abstract

Means for high-density multiparametric physiological mapping and stimulation are critically important in both basic and clinical cardiology. Current conformal electronic systems are essentially 2D sheets, which cannot cover the full epicardial surface or maintain reliable contact for chronic use without sutures or adhesives. Here we create 3D elastic membranes shaped precisely to match the epicardium of the heart via the use of 3D printing, as a platform for deformable arrays of multifunctional sensors, electronic and optoelectronic components. Such integumentary devices completely envelop the heart, in a form-fitting manner, and possess inherent elasticity, providing a mechanically stable bioti-/abiotic interface during normal cardiac cycles. Component examples range from actuators for electrical, thermal and optical stimulation, to sensors for pH, temperature and mechanical strain. The semiconductor materials include silicon, gallium arsenide and gallium nitride, co-integrated with metals, metal oxides and polymers, to provide these and other operational capabilities. Ex vivo physiological experiments demonstrate various functions and methodological possibilities for cardiac research and therapy.

Ultraflexible, large-area, physiological temperature sensors for multipoint measurements

“…The ability to gather information such as pressure and temperature from curvilinear and dynamic surfaces without impairing the movement or usability of the users is unmatched by conventional silicon electronics. There have been reports of the potential application of flexible electrodes on ultrathin substrates (4), flexible sensors that measure biological signals, electrocardiograms, temperature, pressure (5,6), organic amplifier systems (7), high-sensitivity pressure sensors (8), and ultrathin and imperceptible devices (9, 10).…”

A strain-absorbing design for tissue–machine interfaces using a tunable adhesive gel

“…In particular, the mechanical stress induced in dynamically moving tissue, such as that of the heart, has to be minimized during the measurement. With this goal in mind, Rogers and coworkers have manufactured arrays of multiple sensors, including electric probes, pH sensors and strain sensors on a rubber substrate and have successfully used them to measure heart dynamics 11 . Although electrodes coated with gels are expected to exhibit even better biocompatibility, gels have not been employed during the electrical measurements related to highly deformable parts within the body.…”

Blending Electronics with the Human Body: A Pathway toward a Cybernetic Future

“…To this end, ECG has emerged as a simple and low‐cost procedure for recording the electrical activity of the heart, as the only requirements are a set of electrodes, which are either placed on the skin or in close proximity of the heart 365, 366, 367. Albeit, electrodes placed on the skin are noninvasive and capable of real‐time monitoring of heart activity, the reliability and validity of the data obtained from such approaches are still under intensive investigation as these electrodes are not directly in contact with the heart tissue and thus unable to precisely record, measure, and stimulate the beating heart and control its electrical rhythm as compared to implantable ECG devices that are put in direct contact with heart tissue 11, 368. Since most cardiac disorders cause irregular heart beating, the ECG method is a reliable tool for heart diagnosis, as it is pretty straightforward to distinguish between harmonic and nonharmonic electrical recordings from it.…”

“…An alternative system to the silk‐based material strategies was recently developed to further improve recording/stimulation of the cardiac tissue by using ultrathin elastic membranes that matched the complex heart tissue architecture while simultaneously providing excellent electrical contact with important physiological areas on the heart tissue 11. This—next‐generation—ECG device is capable of adhering and enveloping the heart without the need of sutures or tissue glue.…”

“…To remedy the current situation, flexible bioelectronics have emerged, which enable an unusually facile and intimate integration with biological tissues, such as skin, heart, and brain. Notably, they have been applied as brain–machine interfaces8, 9 to treat various neurological disorders, for real‐time monitoring of the beating heart,10, 11 as skin‐based devices that can monitor important health‐markers12, 13 and sophisticated prosthetics with the ability to reestablish a normal life for the hearing disabled,14 the paralyzed,15 and the blind 16. These devices are unequivocally opening new possibilities for studying chronic diseases, improving surgical procedures, and empowering patients to self‐manage their own health.…”