Microchannel-based capillary microfluidics: From simple networks to capillaric circuits

Microfluidics and lab-on-a-chip devices demonstrated the potential advantages for the automation of laboratory workflows and the reduction of sample consumption, reaction time, and assay costs. Capillary microfluidics overcome the limitations of ‘lab-around-a-chip’ by permitting a pre-programmed liquid delivery and flow control to be embedded in the chip without the need for complex peripheral equipment. In this presentation, we chart the progress of microchannel-based capillary microfluidics, from the early stages of the cleanroom environment to the state-of-the-art in rapid prototyping. Following recent progress, we have introduced a new terminology – capillaric circuit (CC) – that both reflects the advances and provides a clear and distinct vocabulary that overcomes the ambiguity due to the multiple usage of the word “capillary”. We briefly describe the governing parameters of self-filling microchannel-based microfluidics CC, and, by analogy with electronic circuits, the deconstruction of CCs into basic fluidic elements and components. The library of basic capillaric elements is expanding. 3D printing enables rapid production of fully functional CCs, establishing CCs as a powerful increasingly complex microfluidic technology that can serve diverse applications.