Micropumps

Micropumps are small fluidic pumps designed to move liquids at the microscale and are commonly integrated into microfluidic systems and MEMS devices. They typically range from fractions of a millimeter to a few millimeters in size and can deliver flow rates from nanoliters to microliters per minute, with some designs achieving higher outputs under specific conditions. By providing on-chip liquid handling, micropumps enable compact, portable analytical systems, medical devices, and cooling solutions for microelectronics.

Most micropumps fall into categories defined by their actuation method. Mechanical diaphragm pumps use a flexible membrane driven by piezoelectric, electrostatic, or pneumatic forces and often rely on integrated valves to produce controlled flow. Peristaltic micropumps employ a sequence of actuated diaphragms to create a traveling wave that moves fluid through microchannels. Electroosmotic micropumps propel liquid via an applied electric field in channels with charged walls, offering smooth flow at low pressures but with sensitivity to fluid conductivity and composition. Other approaches include thermal or vapor bubble–based pumps, which generate pressure differences through localized heating, and magnetic or hybrid actuation schemes that move components externally.

Key considerations for micropumps include integration with microfluidic architectures, power consumption, backpressure tolerance, chemical compatibility, and manufacturing scalability. Advantages of micropumps include low reagent volumes, compact form factors, and the potential for precise, programmable flow control on a chip. Limitations encompass fabrication complexity, sensitivity to fluid properties, limited maximum flow rates, and material constraints affecting biocompatibility and chemical compatibility.

Common applications span lab-on-a-chip diagnostics, high-throughput screening, drug delivery systems, implantable medical devices, and microelectronic cooling. Ongoing research seeks to improve reliability, reduce power, and expand compatible fluids and fabrication materials.