An Autonomous Sensor System for Monitoring Organoid Growth

With advancements in aerospace technology, human space travel becomes more and more feasible with every new development. However, the effects of deep space travel on the human body and human tissue are still unknown. Effects like radiation and long-term microgravity have shown degenerative effects in on-Earth experiments, so it is reasonable to suspect human exploration in deep space could be a dangerous venture. In order to learn more specifically about how deep space travel affects humans, the biologists at the NASA Ames Center RadBio Lab are creating an autonomous lab using human brain organoids to conduct unmanned experiments in deep space using CubeSat satellites. Collaborating with the scientists at NASA, we were tasked with creating a sensor system that would monitor the temperature and the pH of the culture media flowing in and out of the chip. Temperature sensors are necessary to ensure the enclosure that houses the organoids stays habitable throughout the journey, and pH can be used as a proxy for metabolism or flow issues. Since this project is in its early stages, the problem was scoped down from creating a system functional in a CubeSat to a system that can be used to collect data autonomously in a lab at NASA’s Ames Research Center. In order to satisfy the main requirement to not disrupt the flow nor allow a vector for microbial contamination, optical sensors were chosen for both temperature and pH sensing. We utilized infrared temperature sensors to take the temperature of the fluid in the chip and designed a custom spectrophotometric sensor to detect pH in the tube, utilizing the color changing properties of DMEM, the organoid media. The system runs on an Arduino Mega 2560 microcontroller and is fitted with an LCD screen to display these biometrics live, a data collection system to an SD card, and an auditory and visual warning system. Our sensor system was able to provide pH measurements to the required accuracy with a max error of 0.1 pH. Our temperature sensor system gets very close to the required 0.2°C with a max error of 0.24°C. For future work, we would focus on making the system more robust and reliable by designing custom PCBs, improving the measurement accuracy of our sensors, adapting the system to function in a CubeSat, and providing long-range wireless data transmission.