Subcutaneous Solar Energy Harvesting for Self-Powered Wireless Implantable Sensor Systems

Area of Science:

• Biomedical Engineering
• Energy Harvesting
• Implantable Devices

Background:

• Implantable sensor systems require reliable power sources.
• Traditional power sources for implants have limitations like finite lifespan and replacement surgeries.
• Subcutaneous energy harvesting offers a promising alternative for long-term, self-powered implants.

Purpose of the Study:

• To investigate the feasibility of subcutaneous solar energy harvesting for implantable sensor systems.
• To characterize the performance of flexible solar panels beneath biological tissue.
• To develop and evaluate a low-power implantable sensor prototype powered by this harvesting method.

Main Methods:

• Flexible solar panels were tested under 3 mm thick porcine skin under various light conditions.
• Output power was measured across different ambient light intensities.
• A prototype implantable sensor with a power management circuit, temperature sensor, and Bluetooth low energy (BLE) module was designed and implemented.

Main Results:

• The solar panel's output power ranged from tens of micro Watts to a few milli Watts when covered by skin.
• The implantable prototype exhibited an average working current of 400 µA and a sleep current of 7 µA.
• Experimental results confirmed that the subcutaneous solar energy harvester could successfully power the implantable prototype using both sunlight and artificial light.

Conclusions:

• Subcutaneous solar energy harvesting is a viable method for powering implantable sensor systems.
• The developed system can sustain the operation of low-power implantable devices, reducing the need for invasive battery replacements.
• This technology paves the way for advanced, long-term in-vivo monitoring solutions.