Magnets Can Be Used to Connect Microfluidic Devices

Javier Atencia is an investigator that spent a lot of time toying with microfluidic devices, the small, scientific instruments made up of tiny channels that conduct fluids, which can be used for a very wide array of applications, including water diagnostics and decontamination. Like others before him, he came to the decisive bottleneck in this research area, namely to issues related to connecting the microfluidic devices to external pumps and reservoirs. While pondering the problem, he started playing with two magnets. Hearing them snap together gave him an idea.

The idea then transformed into a new, inexpensive, reusable and highly efficient microfluidic connector system that employed a ring magnet around a central tube. This “hose” is then placed directly atop the openings in the microfluidic device, which is itself embedded in glass. The entire ensemble is held together by another ring-shaped magnet, which is placed directly beneath the one in the small hose, only below the glass substrate. The attraction between the two magnets sets the connected device in place, strongly enough to allow for a host of chemical and physical experiments to be conducted. Atencia is a scientist at the National Institutes of Standards and Technology (NIST).

Details of the accomplishment appear in a paper entitled “Magnetic connectors for microfluidic applications,” published online in the November 16 issue of the respected scientific journal Lab on a Chip. The most important thing about the invention is the fact that the system is so effective, that it does not allow for any type of leakage, a common problem met in previous approaches. Some researchers tried to glue the hoses to the inputs and outputs of the devices, but excess glue either entered the channels, or allowed the liquids being analyzed to escape, rendering the studies useless.

The researcher, however, admits that there is a problem with his approach. Well, not really a problem, but a limitation. This type of connections cannot handle experiments dealing with iron-containing (ferro) fluids, superparamagnetic particles – particles so small that their magnetic properties decrease with time and fluctuations in temperature –, as well as cells tagged with magnetic particles, or high-temperatures (greater than 80 degrees Celsius). The magnets would, in these instances, attract the particles on their surface, so the liquids to be studied will not pass through the channels.