• droplet generator
• interlock
• LEGO®-like
• microfluidics
• modularity
• o-ring sealing
• stereolithography
• thermal bonding

A LEGO®-inspired approach to rapidly construct modular microfluidic systems is presented. A typical LEGO®-like microfluidic system consists of multiple modules, each implementing a specific fluidic function and all tougher working to perform more complex operations. Each module (size 15 x 30 x 5 mm) was 3D printed through stereolithography in acrylic resin. LEGO®-like interlocks (i.e., pillar/holes couples) enabled the rapid prototyping of simple (single level) chip as well as complex (multilevel) microfluidic systems. As for the single level module, the interlocks provided a self-alignment means to join two distinct parts– inlet- and channel-blocks. Eventually, thermal bonding allows to seal the two blocks creating a monolithic functional chip. The LEGO®-like interlocks also allowed interconnecting multiple (single level) modules to form modular, complex, and reconfigurable microfluidic systems. To this end, the design of the modules was modified inserting an elastic O-ring between adjacent modules to prevent fluidic leakages at flow rates as high as 100 µL/min. As an example of the modular LEGO®-like microfluidic technology, a functional micro-droplet generator was designed and fabricated. The micro-droplet generator is intended to be the first of many other functional modules that will be printed and then combined as LEGO® bricks.