Systems and method for automated oligonucleotide synthesis

A method of operating a reactor, the method comprising:

• providing a vessel configured to contain a solid support, the vessel comprising:
• a vessel wall defining a reaction chamber,
• the reaction chamber having a first end and a second end opposite the first end,
• a piston operatively arranged at the first end and configured to translate within the reaction chamber,
• the piston comprising a piston head coupled to a piston shaft, and
• the piston head comprising a plurality of crossflow ports disposed therein,
• a force measuring device attached to the piston shaft and configured to measure a load on the piston shaft,
• a piston driver coupled to the piston shaft, and
• a processor operably coupled to the force measuring device and the piston driver;
• measuring, using the processor, a load on the piston shaft using the force measuring device;
• adjusting, using the processor, a position of the piston using the piston driver based on measuring the load on the piston shaft;
• and
• moving, using the processor and via the plurality of crossflow ports, fluid into and out of a space adjacent to the piston head.