Liquid inks can be any material that is liquid at deposition conditions.  The liquid deposition properties are determined by the interactions between the liquid and the tip, the liquid and the surface, and the viscosity of the liquid itself.  These interactions limit the minimum feature size of the liquid ink to about 1 micrometre, depending on the contact angle of the liquid.  Higher viscosities offer greater control over feature size and are desirable.  Unlike molecular inks, it is possible to perform multiplexed depositions using a carrier liquid.  For example, using a viscous buffer, it is possible to directly deposit multiple proteins simultaneously.
*1–10 micrometre feature resolution
*Multiplexed depositions
*Less restrictive ink/surface requirements
*Direct deposition of high viscosity materials