On-demand scalable nano-scale 3D printing system

A 3D printing system comprising:

• a substrate;
• a first syringe pump and a second syringe pump;
• a first syringe coupled to the first syringe pump and a second syringe coupled to the second syringe pump;
• a hydrodynamic flow focusing nozzle having a central channel coupled to the first syringe to receive a printing ink and two side channels disposed on two sides of the central channel and coupled to the second syringe to receive a sheath fluid;
• a pulse generator to apply an electric potential between the hydrodynamic flow focusing nozzle and the substrate to deposit the printing ink on the substrate on-demand and control ejection frequency of the printing ink from the hydrodynamic flow focusing nozzle;
• first means for controlling the first syringe pump to adjust a printing ink flow rate of the printing ink through the first syringe to the central channel of the hydrodynamic flow focusing nozzle to deposit the printing ink onto the substrate;
• and
• second means for controlling the second syringe pump to adjust a sheath fluid flow rate of the sheath fluid through the second syringe to the two side channels of the hydrodynamic flow focusing nozzle to pinch the printing ink in the central channel using the sheath fluid flowing through the two side channels.