A flexible, stretchable system for simultaneous acoustic energy transfer and communication

Abstract

The use of implantable medical devices, including cardiac pacemakers and brain pacemakers, is becoming increasingly prevalent. However, surgically replacing batteries owing to their limited lifetime is a drawback of those devices. Such an operation poses a risk to patients-a problem that, to date, has not yet been solved. Furthermore, current devices are large and rigid, potentially causing patient discomfort after implantation. To address this problem, we developed a thin, battery-free, flexible, implantable system based on flexible electronic technology that can not only achieve wireless recharging and communication simultaneously via ultrasound but also perform many current device functions, including in vivo physiological monitoring and cardiac pacing. To prove this, an animal experiment was conducted involving creating a cardiac arrest model and powering the system by ultrasound. The results showed that it automatically detected abnormal heartbeats and responded by electrically stimulating the heart, demonstrating the device's potential clinical utility for emergent treatment.

Electrical performance optimization of serpentine interconnect for stretchable electronics

“…Although this structure will restrict the out-of-plane displacement of the serpentine interconnect and reduce the stretchability, it corresponds to the actual situation that most flexible sensors are encapsulated with an encapsulation layer [10]. And it also corresponds to the actual situation that the serpentine interconnect in the flexible circuit is encapsulated in the PDMS [11]. The encapsulating film is a transparent and viscous medical dressing (Tegaderm Film, 1624W) with excellent extensibility, waterproofness, breathability and biocompatibility.…”

Flexible ultrasound-induced retinal stimulating piezo-arrays for biomimetic visual prostheses

“…An alternative option for wirelessly driving implantable/wearable electronics is to employ programmable external ultrasound (US) sources, which would provide satisfactory controllability in terms of spatial resolution and electrical output parameters 16 – 18 . Recently, US-driven energy transfer has already established itself as an emerging technology for wireless power transfer and communication 19 – 23 . Compared with EM waves, US could allow wireless power and data transmission through acoustic waves with shorter wavelengths (e.g., millimeter and submillimeter at 1–10-MHz US frequency) 21 , 24 .…”

Ionic communication for implantable bioelectronics

“…Physiologic signals are robustly transmitted by cables because of their simplicity and high data rate capacity, but this approach requires permanent tissue-traversing components that limit their use in chronic applications. Wireless data transmission from implanted devices has been accomplished using radio frequency (RF) and ultrasound-based communication (4)(5)(6)(7)(8)(9)(10). The complex, high-power consumption, nonbiocompatible, and rigid RF electronic components combined with the high ionic conductivity of biological tissue place severe restrictions on its signal transmission capabilities (11)(12)(13).…”

“…As a result, the majority of RF-based systems require tissue-extruding components that interface with a transmitter placed outside the body ( 14 , 15 ). Although ultrasound has better tissue penetration than RF, communication is strongly dependent on the coupling factor between the transmitter and receiver, allowing tissue inhomogeneity and mechanical movements to introduce instability ( 5 , 7 , 8 , 10 , 16 ). Optical methods have high power consumption and are limited by light scattering within tissue ( 17 ).…”