Wireless Power Transfer Strategies for Implantable Bioelectronics

Abstract

Neural implants have emerged over the last decade as highly effective solutions for the treatment of dysfunctions and disorders of the nervous system. These implants establish a direct, often bidirectional, interface to the nervous system, both sensing neural signals and providing therapeutic treatments. As a result of the technological progress and successful clinical demonstrations, completely implantable solutions have become a reality and are now commercially available for the treatment of various functional disorders. Central to this development is the wireless power transfer (WPT) that has enabled implantable medical devices (IMDs) to function for extended durations in mobile subjects. In this review, we present the theory, link design, and challenges, along with their probable solutions for the traditional near-field resonant inductively coupled WPT, capacitively coupled short-ranged WPT, and more recently developed ultrasonic, mid-field, and far-field coupled WPT technologies for implantable applications. A comparison of various power transfer methods based on their power budgets and WPT range follows. Power requirements of specific implants like cochlear, retinal, cortical, and peripheral are also considered and currently available IMD solutions are discussed. Patient's safety concerns with respect to electrical, biological, physical, electromagnetic interference, and cyber security from an implanted neurotech device are also explored in this review. Finally, we discuss and anticipate future developments that will enhance the capabilities of current-day wirelessly powered implants and make them more efficient and integrable with other electronic components in IMDs.

An Overview of Regulation Topologies in Resonant Wireless Power Transfer Systems for Consumer Electronics or Bio-Implants

“…Some previous studies have reviewed the R-WPT techniques [3][4][5][6][7]. In [3,4], the historical background, challenges, and engineering applications of R-WPT were discussed.…”

“…In [3,4], the historical background, challenges, and engineering applications of R-WPT were discussed. The authors in [5] presented the coil design challenges. A comparison between the inductive and capacitive power transfer in power level, gap distance, operating frequency, and efficiency were given in [6].…”

Frequency Splitting Elimination and Cross-Coupling Rejection of Wireless Power Transfer to Multiple Dynamic Receivers

“…Also, MRWPT technology could be the best choice for small power wearable or implanted healthcare devices, such as blood glucose monitors, hearing aids, electrocardiogram, micropumps, pacemakers and insulin pumps [4,5]. Similarly, with the advent of microelectronics and semiconductor technology the size of these devices is shrinking drastically, which makes the device portable or even implantable [6,7]. In the meantime, the number of personal electronic devices used by a person is increasing day by day, which needs to be charged efficiently from a single power source [8].…”

Leadless multisite pacing: A feasibility study using wireless power transfer based on Langendorff rodent heart models

“…Use of an alternative power source may eliminate the need for on‐board batteries, thus significantly reducing the volume of the requisite form factor. Wireless power transfer (WPT) is a method by which radiofrequency (RF) energy is transmitted using electromagnetic induction from a transmitting antenna to a receiving antenna at a given frequency . The present report is the first description of multisite cardiac pacing using WPT.…”

“…Wireless power transfer (WPT) is a method by which radiofrequency (RF) energy is transmitted using electromagnetic induction from a transmitting antenna to a receiving antenna at a given frequency. [12][13][14] The present report is the first description of multisite cardiac pacing using WPT.…”