A bioreactor is a combination of both Electronics, Computer science and Biology. But during experimentation we do need to separate them from each other. We thus build a few setup modules that held each one of our devices so that we could set them up together for starting experimentation. The constructions have been differentiated as follows:
Pump and Circuit House:
The pumps vibrate due to high friction generated between the plexiglass and ball bearing. To hold this tight we need a casing. Also we see that each reactor needs three pumps so we developed a complete box that can hold the pumps as well as the circuit. Even though they are in a same box, they are separated with a middle layer so that it gives extra support to the pumps. A window is made between these two layers for the wires from the pump to reach the circuit. Small windows are also cut on the outer cover so as to connect the supply, USB, etc.
Foundation
The stirring is done using a DC Motor and the concept of magnetism. Therefore it has to be placed just below the reactor. Aligning the reactor and the DC Motor is very important so that the magnetic stirrer inside the reactor flask can spin in a constant motion. This alignment is achieved by our Foundation structure. It consists of a base plate that holds a simple but strong box like structure. Inside this box is floors or layers with three holes, each one at a certain gap from each other. The diameter of these holes are the same as the diameter of the DC Motor. These layers help to make the DC Motor stand and not wobble due to its motion. The wiring of the motors are done inside the box with open ended connections coming out of a cut window.
Water Bath
A Bioreactor is always maintained in a constant temperature suited to the microorganisms, preferablly 37 degrees. We achieve this by building our own waterbath with out of plexiglass. The side walls are cut with a 5 mm thick plexiglass but the base plate is 2 mm thick. This is to decrease the distance between the magnetic stirrer inside the reactor and the magnets stuck on our DC Motor. The two small side walls have notches with increased length so that the water bath can sit in place on top of our foundation structure described above. The structure consists of two holes of one of the small side walls which allows the movement of water in and out of the bath from an external heating device. This structure is glues to make it water proof.
Inside this structure there are two levels that help the reactor to stand in place. Just like the motor plates in the foundation structure, these plates have holes with the diameter similar to the diameter of our reactor vessels. These layers are also responsible for the alignment of the reactor and the stirrer.
OD And Needle Holder
The bioreactors we use are small flasks with a septum. This septum is pearced with needles to connect it to external fluids or air via the pumps. One of these needles must also be connected through the OD device. This complicated and unsteady outlets are held together and organised by our Holder structure. It is a simple Umbrella like structure that sits on the water bath. It has got slits through which the needles can come out and still be erect. The OD structure is also help in place between two walls cut out of 2 mm plexiglass.
Files
The Structural Setup of the Bioreactor we developed can be connstructed just with 5 pieces of 5 mm (250x600 mm) and 2 pieces of 2 mm (250x600 mm) Plexiglas. the files for Lasercutting can be found Aachen_Lasercutter_files.zip