Conformal piezoelectric systems for clinical and experimental characterization of soft tissue biomechanics

Abstract

Mechanical assessment of soft biological tissues and organs has broad relevance in clinical diagnosis and treatment of disease. Existing characterization methods are invasive, lack microscale spatial resolution, and are tailored only for specific regions of the body under quasi-static conditions. Here, we develop conformal and piezoelectric devices that enable in vivo measurements of soft tissue viscoelasticity in the near-surface regions of the epidermis. These systems achieve conformal contact with the underlying complex topography and texture of the targeted skin, as well as other organ surfaces, under both quasi-static and dynamic conditions. Experimental and theoretical characterization of the responses of piezoelectric actuator-sensor pairs laminated on a variety of soft biological tissues and organ systems in animal models provide information on the operation of the devices. Studies on human subjects establish the clinical significance of these devices for rapid and non-invasive characterization of skin mechanical properties.

Highly flexible, wearable, and disposable cardiac biosensors for remote and ambulatory monitoring

“…[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] These novel epidermal devices contain soft, conformal sensors and associated circuits embedded in ultrathin encapsulating layers that achieve intimate skin coupling. 25,34 Here, we present a highly flexible epidermal design and clinical implementation of a novel ECG and heart rate logging wearable sensor, henceforth referred to as "WiSP", which is low cost, light-weight (1.2 g), and capable of energy harvesting.…”

Soft, thin skin-mounted power management systems and their use in wireless thermography

“…Such stretchable characteristics are qualitatively different from those afforded by simple mechanical bendability; the consequences are important because such properties allow for intimate, long-lived interfaces with the human body, such as the skin (5,6), heart (7), and the brain (8), and for development of unusual device designs that derive inspiration from biology (9,10). Many impressive examples of the utility of these concepts have emerged over the last several years, particularly in the area of biomedical devices, where work in skin-mounted technologies is now moving from laboratory demonstrations to devices with proven utility in human clinical studies (11,12) and even to recently launched commercial products (13). Although schemes in high-frequency or ultrahigh-frequency wireless power transfer satisfy requirements in many important contexts (14,15), opportunities remain for approaches in local generation and/or storage of power in ways that retain overall stretchable characteristics at the system level.…”

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

“…Therefore, conformal bioelectronics that enables real‐time monitoring of the mechanical properties of skin can be used to detect potentially life‐threatening and chronic diseases in the home rather than in the clinic 290, 291. Over the years a wide‐range of these so‐called “e‐skin” devices have been developed for healthcare monitoring purposes 12, 62, 284, 289, 292, 293. In simple terms, e‐skin devices are flexible sensing networks with accurate spatial mapping and detection capabilities that enable unmatched recordings of the mechanical metrics of skin.…”