Organoids are 3D cellular structures for organ modeling and drug testing. Retinal organoids are needed to study diseases like retinoblastoma; however, their development is particularly difficult. To form inner retina cells, the organoids need to be in a hypoxic state, yet the outer retina cells consume more oxygen than any other tissue in the body. It is possible to simulate this environment with a bioreactor by utilizing an open well design for ease of use. To accommodate the culture media consumption without disturbing the organoids in the open wells, it requires an external microfluidic system. A KD Scientific syringe pump with four 30 mL syringes simultaneously infuses and withdraws 600 nL of media per minute through 1/32 inch autoclavable Tygon tubing. The tubing is connected to the bioreactor through an innovative housing device that uses Stereolithography 3D printing technology with a specialized resin. Unlike most 3D printed plastics, the resin is autoclavable for sterilization and incubation. The tubing can be seamlessly and quickly removed and replaced to monitor the bioreactor without disturbance.Simulations using COMSOL show that the oxygen gradient is not affected by the fluid flow, which is confirmed by our measurements using an oxygen sensor. Implementation of the system resulted in successful organoid survival over a period of multiple weeks. Although testing is required to confirm the bioreactor can be imaged within the container, the system is a promising option for providing culture media to an open well organoid bioreactors over long periods of time.
