A Fully Biodegradable Battery for Self‐Powered Transient Implants

Abstract

Biodegradable transient devices represent an emerging type of electronics that could play an essential role in medical therapeutic/diagnostic processes, such as wound healing and tissue regeneration. The associated biodegradable power sources, however, remain as a major challenge toward future clinical applications, as the demonstrated electrical stimulation and sensing functions are limited by wired external power or wireless energy harvesters via near-field coupling. Here, materials' strategies and fabrication schemes that enable a high-performance fully biodegradable magnesium-molybdenum trioxide battery as an alternative approach for an in vivo on-board power supply are reported. The battery can deliver a stable high output voltage as well as prolonged lifetime that could satisfy requirements of representative implantable electronics. The battery is fully biodegradable and demonstrates desirable biocompatibility. The battery system provides a promising solution to advanced energy harvesters for self-powered transient bioresorbable implants as well as eco-friendly electronics.

Bioresorbable Materials on the Rise: From Electronic Components and Physical Sensors to In Vivo Monitoring Systems

“…Copyright 2015, Springer Nature. c) Left: Sketch of the structure of the layered‐cathode battery . Middle‐left: Photograph of continuous powering of a LED after 16 h of immersion in PBS.…”

“…Right: Battery discharge under a constant current density of 25 µA cm −2 . Reproduced with permission . Copyright 2018, John Wiley and Sons.…”

“…More recently (2018), Huang et al developed a magnesium‐molybdenum oxide (Mg–MoO 3 ) bioresorbable battery with extended lifetime using calcium crosslinked alginate in PBS as electrolyte‐retaining polymer (Figure c). The anode was a magnesium foil (200 µm) and the cathode consisted of MoO 3 nanoparticles mixed with PLGA and cast (150 µm) on Mo foil (30 µm).…”

Materials Strategies and Device Architectures of Emerging Power Supply Devices for Implantable Bioelectronics

“…also possess good biocompatibility, as well as high energy densities, and are therefore widely applicable as electrodes in batteries or interconnect materials in power devices . Composite materials involving formation of networks of active materials in a biocompatible soft polymer matrix represent an alternative approach . If the implantable systems are designed for short or mid‐term application, biodegradable characteristics are desirable, so as to eliminate the need for a second surgery for device retrieval .…”

“…Adopting biodegradable materials into the device systems will be critically important, including the metals and oxides acting as electrodes or interconnects (Mg, Mg alloy, Zn, iron (Fe), molybdenum (Mo), silicon dioxide (SiO 2 ), magnesium oxide (MgO), molybdenum trioxide (MoO 3 ), etc. ); polymers acting as dielectrics, electrolytes or encapsulations (poly lactic‐ co ‐glycolic acid (PLGA), polycaprolactone (PCL), polyanhydride, alginate, etc. ); and semiconductors (silicon (Si), silicon germanium alloy (SiGe), indium–gallium–zinc‐oxide (IGZO), etc.)…”