Can you explain the different dispensing techniques?

Answer

While you could organize this information in different ways, I think of it as the use of contact methods vs. noncontact methods of dispensing.

Contact Methods (also referred to as “extrusion”, as one would extrude the material out from the tip of a pipette/syringe; the tip comes close enough to the substrate for the material to make contact)
Air pulse (pneumatics push the fluid down the syringe barrel)
Displacement syringe (piston pushes fluid down the barrel)
Screw (screw motion pulls fluid down the barrel)

Noncontact Methods (produces droplets, which shoot at a substrate from a specified distance)
Jet – there are different types like piezo, thermal, mechanical
Laser – uses pulsed laser beam to generate droplets
Acoustic – uses acoustic energy to generate droplets
Photopolymerization – (stereolithography and related techniques)

Note: some people are erroneously calling the technique of magnetic levitation (used for creating 3D cultures) a type of bioprinting, when I would argue that it is not. It does not depend on a particular kind of printing, but rather on interactions between magnetic nanoparticles incorporated into the cells and an external magnet.