Active photonic wireless power transfer into live tissues

Abstract

<jats:p>Recent advances in soft materials and mechanics activate development of many new types of electrical medical implants. Electronic implants that provide exceptional functions, however, usually require more electrical power, resulting in shorter period of usages although many approaches have been suggested to harvest electrical power in human bodies by resolving the issues related to power density, biocompatibility, tissue damage, and others. Here, we report an active photonic power transfer approach at the level of a full system to secure sustainable electrical power in human bodies. The active photonic power transfer system consists of a pair of the skin-attachable photon source patch and the photovoltaic device array integrated in a flexible medical implant. The skin-attachable patch actively emits photons that can penetrate through live tissues to be captured by the photovoltaic devices in a medical implant. The wireless power transfer system is very simple, e.g., active power transfer in direct current (DC) to DC without extra circuits, and can be used for implantable medical electronics regardless of weather, covering by clothes, in indoor or outdoor at day and night. We demonstrate feasibility of the approach by presenting thermal and mechanical compatibility with soft live tissues while generating enough electrical power in live bodies through <jats:italic>in vivo</jats:italic> animal experiments. We expect that the results enable long-term use of currently available implants in addition to accelerating emerging types of electrical implants that require higher power to provide diverse convenient diagnostic and therapeutic functions in human bodies.</jats:p>

Potential of subdermal solar energy harvesting for medical device applications based on worldwide meteorological data

“…Subdermal solar cells can actively recharge electronic implants using an artificial light source, similar to inductive charging. A recently published study 18 investigated the concept of active photonic power transfer and presented its feasibility during an in vivo trial. The study suggested the use of a skin attachable light emitting patch that constantly illuminates the subdermal solar cell at a wavelengths 670 nm, because the energy per photon and the skin transmittance presented in the study are both high.…”

“…An ex vivo trial covered a solar module with a porcine skin flap and analyzed the generated power. 16 The in vivo animal trials were performed in mice 17 , 18 and pigs. 19 , 20 All trials reported promising results in the range of 1.9 to of generated power by subdermal solar modules at an implantable size scale under midday solar irradiation (AM1.5G).…”

Wireless Bioelectronic Devices Driven by Deep Red Light

“…However, transducers based on photovoltaics operated in the tissue transparency region (as discussed in Section 4.2.4) have been demonstrated in stimulators for peripheral nerves, spinal cord, or for powering of pacemakers. [117][118][119][120][121] Typically, inorganic solar cells based on p-i-n silicon or gallium arsenide have been used to power medical implants because of their action spectrum overlap with the tissue transparency window and their high power conversion efficiencies up to 45%. 117,118,122 However, relatively thick material layers are necessary to absorb the light efficiently, thus the devices are quite bulky and rigid.…”

Implications of Wound Healing on Subcutaneous Photovoltaic Energy Harvesting

“…Moreover, an ex-vivo trial irradiated a photovoltaic module below a flap of porcine skin [14]. Acute in-vivo trials with implanted photovoltaic modules in mice [15], [16] and pigs [17], [18] showed promising power outputs. The trials showed that subcutaneous photovoltaic modules at implantable size scales can generate between 2-10 mW cm −2 under midday solar irradiation.…”