Open-channel microfluidics via resonant wireless power transfer.

Area of Science:

• Microfluidics
• Biosensing
• Electrical Engineering

Background:

• Open-channel microfluidics offers precise liquid handling for integrated systems.
• Existing methods like electrowetting have limitations in confinement, while dielectric polarization requires high voltages.
• There is a need for low-voltage, open-channel microfluidic systems compatible with various solutions.

Purpose of the Study:

• To demonstrate low-voltage actuation of narrow open microchannels.
• To develop a wireless, tube-free microfluidic system for practical applications.
• To enable smartphone-driven fluidic control for enhanced biosensing and microscopy.

Main Methods:

• Utilized resonant, nanoscale focusing of radio frequency (RF) power.
• Designed novel electrode geometry to overcome surface tension effects.
• Employed low operating voltages (0.5 V_RMS) for actuating microchannels down to 1 µm.

Main Results:

• Achieved actuation of microchannels as narrow as 1 µm with deionized water and physiological buffer at 0.5 V_RMS.
• Demonstrated practical applications: open mixing, protein labeling, filtration, and viral transport.
• Integrated resonant wireless power transfer for a completely hardware-free system.

Conclusions:

• This technology overcomes limitations of existing microfluidic actuation methods.
• The wireless, low-voltage system is ideal for sensitive applications like high-numerical-aperture microscopy.
• Smartphone-driven control showcases the potential for widespread adoption in portable biosensing.