Wafer-Level Process for Single-Use Buckling-Film Microliter-Range Pumps

In this paper, we present the development of disposable single-use microfluidic pumps entirely based on a straightforward wafer-level fabrication scheme, which allows for precise integrated active dosing in the microliter range. To accomplish stroke-lengths needed for microliter-range applications, we utilize a new method of bending of a unimorph-composite-actuator film. The unimorph composite actuator consists of a temperature-sensitive silicone elastomer composite, i.e., polydimethylsiloxane, with incorporated expandable microspheres. The fabricated micropumps successfully demonstrated precise liquid-volume control, both at low and high flow rates, and show a standard deviation of 6.7% for consecutive pump experiments. Moreover, the method of fluorescent thermometry was used to measure the thermal load on liquid volumes dispensed with the micropumps. The liquid temperature reaches a maximum of 50degC during the operation. The presented fully integrated single-use micropumps are electrically controllable, do not require external means for liquid actuation, are made of low-cost materials only, and might potentially be used in drug-delivery applications.