A Peristaltic Micropump Based on the Fast Electrochemical Actuator: Design, Fabrication, and Preliminary Testing

Microfluidic devices providing an accurate delivery of fluids at required rates are of considerable interest, especially for the biomedical field. The progress is limited by the lack of micropumps, which are compact, have high performance, and are compatible with standard microfabrication. This paper describes a micropump based on a new driving principle. The pump contains three membrane actuators operating peristaltically. The actuators are driven by nanobubbles of hydrogen and oxygen, which are generated in the chamber by a series of short voltage pulses of alternating polarity applied to the electrodes. This process guaranties the response time of the actuators to be much shorter than that of any other electrochemical device. The main part of the pump has a size of about 3 mm, which is an order of magnitude smaller in comparison with conventional micropumps. The pump is fabricated in glass and silicon wafers using standard cleanroom processes. The channels are formed in SU-8 photoresist and the membrane is made of SiNx. The channels are sealed by two processes of bonding between SU-8 and SiNx. Functionality of the channels and membranes is demonstrated. A defect of electrodes related to the lift-off fabrication procedure did not allow a demonstration of the pumping process although a flow rate of 1.5 µl/min and dosage accuracy of 0.25 nl are expected. The working characteristics of the pump make it attractive for the use in portable drug delivery systems, but the fabrication technology must be improved.

Design and Fabrication of Integrated Microchannel and Peristaltic Micropump System for Inertial Particle Separation

In particle separation applications, conventional syringe pumps are widely used to supply fluid flow into microchannels at a controlled flow rate. However, their bulky structures lack the development of compact particle separation systems which is essential for all LoC (Lab on a Chip) systems. In this study, we designed and fabricated a peristaltic micropump which can be integrated into an inertial particle separation microchannel at the same layer with a compact design. Since inertial particle separation can be done without a need for an external force field, we aimed to develop a μTAS (Micro Total Analysis Systems) system which is able to realize particle separation in an integrated micropump-microchannel system. The circular micropump channel made of two PDMS layers and its width is optimized. The 3D-Printed micropump is actuated by a stepper motor, and the rate of pumped fluid is monitored by an LCD screen connected and programmed to system according to the system parameters. Micropump has a theoretical capacity of supplying particle carrying fluid at the flow rate of 25.47 ml/min when the stepper motor is rotated at 330 rpm.

Microfluidic diafiltration-on-chip using an integrated magnetic peristaltic micropump

A novel magnetically-driven peristaltic pump can be used to drive cyclic on-chip flow for small volume (50 μL) diafiltration.

Peristaltic Micropump with Multi-Electrodes Using Electrostatic Force

An electrostatically driven multi-electrode peristaltic micropump has been developed for pumping microfluid through μ-TAS. Peristaltic-type micropumps have been reported to address many of the problems of micropumps in general and electrostatic actuation in particular. Peristaltic motion can eliminate the need for valves and for proper valve timing or for a nozzle/diffuser in designing flow control, as well as contribute to reduce the dead volume which can be a critical problem for micropump to achieve higher back pressures. In this paper, we present an electrostatically driven bidirectional peristaltic micropump that was designed, fabricated, and characterized. It was fabricated on a silicon substrate with a polyimide membrane. It was consisted of single large chamber, PI membrane operated with 4 electrodes, and 4 phase sequencing actuation. The displacement of the meniscus in the capillary tube is observed and recorded by using a video camera. The micropump was operated from 115V to 135V. The maximum moving speed of the meniscus was approximately 24 mm/min at 2.2 kHz at 115V. This pump will be applied to various microfluidic fields.