If you would like to experiment with microfluidics — observing the behavior of extremely small changes in the volume of liquids — Poseidon from a team at the California Institute of Technology presents a new option. The stepper-driven system costs less than $400, and can be assembled in an hour (though certainly excluding print time). The device uses a trio of stepper motors to push liquid out of syringes at a flow rate that you dictate via a graphical user interface.
A more detailed explanation on how Poseidon works is shown in the second video below, which will be familiar to those that dabble in CNC machinery. Three steppers are used here under Arduino/CNC shield control, but one could see this number being higher or lower depending on what kind of experimental setup is needed.
Along with a versatile fluid transfer rig, the design includes a Raspberry Pi-based microscope control station, furnishing everything you need to get started with this scientific pursuit at a very reasonable price.