A simple and cheap custom-made plastic 3D printed pump can be utilized to drive a variety of syringes, varying from classical ml range syringes, to very low volume Hamilton syringes. This simple equipment, if well controlled, can successfully replace in the lab most of the very expensive injectomates available for research use.

A metallic high-torque mini servo (our model is designed to encase this type of servo: https://www.pololu.com/product/997) can be very precisely controlled utilizing a cheap DC-DC Step Down Converter.

The schematic diagram showed below illustrates the main parts of this pump, and each individual part is freely available for download as a .stl file (designed utilising Autodesk Tinkercad). Our model has been printed using a Tiertime UpBoxPlus 3D printer, 1.75 mm-thick Tiertime PLA filament, at the highest density meshwork available from this printer (0.2 mm layer thickness).

Files list:

- Servo support (download ZIP file)

- Base (download ZIP file)

- Servo coupling (download ZIP file)

- Piston (download ZIP file)

- Micro syringe holder (download ZIP file)

Below is a view of our working model, utilized for slow injection of µl-order volumes (2 minutes for 1ml). The inset represents the speed and sense control unit. The needle of the Hamilton syringe is hydraulically connected with the injection glass pipette using Teflon inextensible tubing (0.5 mm inner diameter), and gun silicone oil.