Wireless Power Transfer and Telemetry for Implantable Bioelectronics

Abstract

Implantable bioelectronic devices are becoming useful and prospective solutions for various diseases owing to their ability to monitor or manipulate body functions. However, conventional implantable devices (e.g., pacemaker and neurostimulator) are still bulky and rigid, which is mostly due to the energy storage component. In addition to mechanical mismatch between the bulky and rigid implantable device and the soft human tissue, another significant drawback is that the entire device should be surgically replaced once the initially stored energy is exhausted. Besides, retrieving physiological information across a closed epidermis is a tricky procedure. However, wireless interfaces for power and data transfer utilizing radio frequency (RF) microwave offer a promising solution for resolving such issues. While the RF interfacing devices for power and data transfer are extensively investigated and developed using conventional electronics, their application to implantable bioelectronics is still a challenge owing to the constraints and requirements of in vivo environments, such as mechanical softness, small module size, tissue attenuation, and biocompatibility. This work elucidates the recent advances in RF‐based power transfer and telemetry for implantable bioelectronics to tackle such challenges.

Wide-range robust wireless power transfer using heterogeneously coupled and flippable neutrals in parity-time symmetry

“…Implantable bioelectronic devices have been widely used to monitor physiological and electrophysiological signals (e.g., heart signal, glucose, and blood pressure) and/or to stimulate organs and nerves (e.g., heart and auditory nerves) (40)(41)(42). However, such devices mostly rely on batteries that require periodic surgery for replacement (42)(43)(44). As devices including batteries are rigid, mechanical mismatch between the device and soft human body occurs, which imposes continuous stress on the target tissue and causes inflammatory responses.…”

Soft Implantable Bioelectronics

“…Meanwhile, the long-term, sustainable operation of implantable devices with excellent stability is also associated with their power sources. Among the different methods of power delivery, − the method of supplying power self-harnessed from the dynamic micromotions of tissues inside the human body has recently been highlighted. Such energy harvesting devices can convert the intracorporeal kinetic energy into electrical power, but challenges remain, such as constant power supply and insufficient power generation.…”

“…(i) Pulses released by the pacemaker, powered using an external battery or the implanted device. (a–d) Reproduced with permission from ref . Copyright 2020 Springer Nature.…”

“…Copyright 2020 Springer Nature. (e–i) Reproduced with permission from ref . Copyright 2020 Springer Nature.…”

Skin Electronics from Biocompatible In Situ Welding Enabled By Intrinsically Sticky Conductors

“…At present, most reported skin electronics cannot form a reliable adhesion to the skin, and they usually come into contact with human tissues (such as the skin and the heart) through tapes, bands, or van der Waals forces. [ 9 , 10 , 11 , 12 ] When the tissue is deformed, the soft electronic device cannot be deformed simultaneously with the tissue due to insufficient adhesion between the device and the tissue, which will result in the detachment of the measurement interfaces and cause measurement errors (e.g., the detachment of the electrode–skin interface will cause huge noise for the electrophysiological measurement). [ 13 , 14 ] Some hydrogels are reported to be soft, conductive, and sticky at the same time.…”