MIT engineers have introduced an element of fun into microfluidics.

The field of microfluidics involves minute devices that precisely manipulate fluids at submillimeter scales. Such devices typically take the form of flat, two-dimensional chips, etched with tiny channels and ports that are arranged to perform various operations, such as mixing, sorting, pumping, and storing fluids as they flow.

The MIT team, looking beyond such lab-on-a-chip designs, found an alternative microfluidics platform in "interlocking injection-molded blocks" or, as most of us know them, LEGO bricks.

"LEGOs are fascinating examples of precision and modularity in everyday manufactured objects," says Anastasios John Hart, associate professor of mechanical engineering at MIT.

Indeed, LEGO bricks are manufactured so consistently that no matter where in the world they are found, any two bricks are guaranteed to line up and snap securely in place. Given this high degree of precision and consistency, the MIT researchers chose LEGO bricks as the basis for a new modular microfluidic design.

The team micro-milled small channels into LEGOs and positioned the outlet of each "fluidic brick" to line up precisely with the inlet of another brick. The researchers then sealed the walls of each modified brick with an adhesive, enabling modular devices to be easily assembled and reconfigured.

Each brick can be designed with a particular pattern of channels to perform a specific task. The researchers have so far engineered bricks as fluid resistors and mixers, as well as droplet generators. Their fluidic bricks can be snapped together or taken apart to form modular microfluidic devices that perform various biological operations, such as sorting cells, mixing fluids, and filtering out molecules of interest.

"You could then build a microfluidic system similarly to how you would build a LEGO castle – brick by brick," says Crystal Owens, a graduate student in MIT's Department of Mechanical Engineering. "We hope in the future, others might use LEGO bricks to make a kit of microfluidic tools."