Bioreactor Temperature Control System Using PID Controller

Abstract

Bioreactors are engineered physiological environment that can be used to study and grow tissue and organ systems in vitro. They are used to subject the cells to physiologically relevant stimulus such as tensile or compressive stress, bending, torsion or fluid flow. An optimal internal environment of a bioreactor should remain sterile while maintaining the viability of tissue, cells and biomolecules at 37°C (normal body temperature) with a tolerance of + or −0.1 °C. This study presents an Arduino microcontroller-based temperature-controlled system using an autotuning proportional integral derivative (PID) control for a small-scale bioreactor. A table top bioreactor temperature control system was designed, fabricated and assembled with laser cut acrylic enclosure. The closed-loop control system maintained the set temperature of 37°C using a tuned PID controller that used a high precision TMP117 sensor for feedback, and controlled the heating element accordingly. The system achieved the desired performance characteristics such as a fast rise time, settling time, low overshoot and low steady state error. Once the system achieved the steady state, it maintained the temperature at 37 ± 0.1 °C. Since the temperature control can vary and monitor fine changes in the environment, the system can be used to study an impact of temperature variations on cell response such as growth and differentiation.