Microfluidic Connector Relies on Magnetism

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The microchip has five inlets and one outlet, all linked to tubing via the magnetic connectors. The inset at upper right shows the setup of the tube-magnet combination. Image: G. Cooksey, NIST

Designing microfluidic devices presents a variety of challenges, many of which are intrinsically tied to the small size of the products and their parts. Among the most frustrating design aspects of the miniature devices, according to researchers at the National Institute of Standards and Technology (NIST; Gaithersburg, MD), are the connectors that form the fluid pathways from external liquid pumps and regulators to the chip. Taking matters into their own hands, the NIST scientists have developed a new magnetic connector that they believe will improve microfluidic device design.Typically, connectors for microfluidic applications require gluing the tubing directly to the chip or employing a male-female connection that joins the tubing to the male component. But these methods are associated with many potential flaws and defects, such as broken bonds or leaks, cracked chips from heat-curing the glue, or devices rendered unusable from rogue glue that runs into the channels. Using magnets as the basis for the connection, the NIST connectors avoid these potential risk factors, however.The scientists' connector for microfluidic applications consists of a ring magnet engineered with an O-ring gasket on its underside and a tube in the center. The tube is positioned directly on top of the inlet or outlet port of a channel in the chip. To secure the magnet and tubing in place, a disc magnet goes on the bottom of the chip. In addition to being cost-effective, the connector is flexible, reliable, and enables quick assembly of the connection. Furthermore, it is reusable, unlike existing microfluidic connectors, the researchers claim. The magnetic connector appears to be suitable for use with most microfluidic devices, with the exception of iron-containing fluids, superparamagnetic particles, cells with magnetic particles, and temperatures greater than 80°C.Click here to view a video demonstrating assembly and use of the connectors with a microfluidic chip.