An Implantable Ultrasonically Powered System for Optogenetic Stimulation with Power-Efficient Active Rectifier and...

Area of Science:

• Biomedical Engineering
• Neuroscience
• Electrical Engineering

Background:

• Parkinson's Disease (PD) is a neurodegenerative disorder impacting motor control.
• Optogenetic stimulation offers a potential therapeutic approach for PD.
• Efficient wireless power transfer is crucial for implantable microdevices.

Purpose of the Study:

• To present a novel micro-scale ultrasonically powered optogenetic microstimulator for PD treatment.
• To enhance the power conversion efficiency of the microstimulator's active rectifier.
• To demonstrate a proof-of-concept system for ultrasonic power transfer and optogenetic activation.

Main Methods:

• Designed and fabricated a microstimulator in TSMC 0.18μm CMOS technology.
• Implemented a power-efficient active rectifier with a novel comparator powering approach.
• Integrated a double-pass regulator, current reference, burst detection circuit, piezoelectric receiver, and blue micro-LED.

Main Results:

• Achieved a voltage conversion ratio of 81% and power conversion efficiency up to 72% for the active rectifier.
• Demonstrated successful ultrasonic power transfer and optogenetic stimulation in a water tank.
• Measured output DC power of 12.7μW and light intensity of 0.11mW/mm² at a specific acoustic intensity.

Conclusions:

• The developed microstimulator system shows promise for wireless optogenetic therapy in Parkinson's Disease.
• The novel powering approach significantly improves active rectifier efficiency.
• Further development could lead to more effective and less invasive PD treatments.