A Miniaturized Wireless Micropump Enabled by Confined Acoustic Streaming

Area of Science:

• Biomedical Engineering
• Microelectromechanical Systems (MEMS)
• Acoustic Devices

Background:

• Miniaturization of healthcare systems is crucial for point-of-care testing (POCT).
• Micropumps are critical components but face performance limitations at small scales.
• Existing acoustic micropumps exhibit suboptimal energy transduction efficiency.

Purpose of the Study:

• To develop a highly efficient and miniaturized acoustic micropump for POCT.
• To improve pumping performance (pressure and flow rate) at the microscale.
• To demonstrate the feasibility of the micropump in a wearable drug delivery system.

Main Methods:

• Fabrication of a microelectromechanical system (MEMS) acoustic micropump using an ultrahigh-frequency bulk acoustic wave resonator.
• Implementation of an inner-boundary-confined acoustic jet for unidirectional flow.
• Integration into a wearable, wirelessly powered drug delivery system (9x9x9 mm³, 1.16 g).

Main Results:

• Achieved high pressure/size (32.620 kPa/cm³) and flow rate/size (11.800 ml/min∙cm³).
• Demonstrated a 2-order-of-magnitude improvement in energy transduction efficiency compared to existing acoustic micropumps.
• Successfully demonstrated in animal models for ocular disease treatment and a human pilot test.

Conclusions:

• The developed acoustic micropump offers superior performance, miniaturization, and low power consumption.
• Its complementary metal-oxide-semiconductor (CMOS) compatibility facilitates integration into various POCT devices.
• The micropump is a promising technology for clinical diagnosis, prognosis, and drug delivery systems.