Indirect Temperature Measurement and Control Method for Cell Culture Devices

Microfluidic devices are promising tools with which to create an environment that mimics a cell's natural microenvironment more closely than traditional macroscopic cell culture approaches. In these devices, temperature is one of the most important environmental factors to monitor and control. However, direct temperature measurement at the cell area can disturb cell growth and potentially prevent optical monitoring, and is typically difficult to implement. On the other hand, indirect measurement could overcome these challenges. Therefore, using the system identification method, we have developed models to estimate the cell area temperature from external measurements without interfering cells. In order to validate the proposed models, we performed large sets of experiments. The results show that the models are able to catch the dynamics of temperature in a desired area with a high level of accuracy, which means that indirect temperature measurement using the model can be implemented in the future cell culture studies. The usefulness of the model is also demonstrated by simulations that use estimated temperature as a feedback signal in a closed-loop system. We also present tuning of a model-based controller and a noise study, which shows that the tuned controller is robust for typical ambient room temperature variations.