Multichannel power electronics and magnetic nanoparticles for selective thermal magnetogenetics

Area of Science:

• Biomedical Engineering
• Materials Science
• Electrical Engineering

Background:

• Magnetothermal-neurostimulation offers a promising avenue for targeted therapeutic interventions.
• Current systems face limitations in speed, flexibility, and precise control of magnetic nanoparticle actuation.
• A wide frequency range is crucial for actuating nanoparticles with diverse magnetic properties.

Purpose of the Study:

• To develop and characterize a power electronics system for frequency-multiplexed magnetothermal-neurostimulation.
• To enable rapid channel switching and precise control over magnetic nanoparticle actuation.
• To demonstrate the system's capability with novel magnetic nanoparticle compositions.

Main Methods:

• A hybrid silicon (Si) and gallium-nitride (GaN) power electronics system was designed to generate alternating magnetic fields from 50 kHz to 5 MHz.
• Three series resonance channels were implemented using capacitor banks and multiplexed via high-voltage contactors.
• The system's performance was evaluated through frequency, field strength, switching time, and stability measurements, alongside nanoparticle heating experiments.

Main Results:

• The system successfully achieved target magnetic field strengths across three distinct frequency channels.
• Rapid channel switching, on the order of milliseconds, was demonstrated.
• Selective heating of various iron oxide nanoparticles, including a novel megahertz-range responsive composition, was confirmed via specific absorption rate and thermal imaging.

Conclusions:

• The developed hybrid Si/GaN power electronics system provides efficient and fast frequency-multiplexed nanoparticle actuation.
• This technology significantly enhances the speed and flexibility of magnetothermal-neurostimulation.
• It offers a technical foundation for selective neural stimulation beyond fundamental spatial focality limits.