In this schematic, the wavy lines depict the fluid flow through a single microfluidic channel. (Credit: Northwestern)

The sheer size of the external equipment required for controlling microfluidics has limited their use in portable, wearable technologies. Now have discovered how to pre-program the devices’ network structures in a way that controls how fluids flow and mix throughout the micropipes.

Microfluidic systems are miniaturized chemical labs formed by a network of pipes used for applications ranging from conducting small-scale experiments to performing complex medical diagnostics, drug delivery and health monitoring.

To perform complicated tests and experiments, multiple fluids need to flow, mix, react, separate and switch directions all within these tiny networks. Each activity requires a pressure pump, and each pump is controlled by an external device.

The researchers designed a microfluidic network in which all mixing sequences are pre-programmed. In their design, one source of applied pressure controls the fluids within the network. By designing how much pressure is needed and the location where pressure is applied, the researchers predetermined how the fluid flowed through the network.