Optical monitoring during bioreactor conditioning of tissue-engineered heart valves.

Currently, one approach to tissue engineering has been to develop in vitro conditions to fabricate functional cardiovascular structures such as heart valves before final implantation. In vivo conditions are simulated using a bioreactor system that supplies cells with oxygen and culture media while providing mechanical stimulation to promote tissue maturation. In our experiment, we developed a novel combined optical monitoring and conditioning device. The entire system is made of acrylic glass and is completely transparent. The bioreactor is connected to an air-driven respirator pump, and the cell culture medium continuously circulates through a closed-loop system. By adjusting stroke volume, stroke rate, and inspiration/expiration time of the ventilator, the system allows various pulsatile flows and different levels of pressure. Our optical monitoring and conditioning device provides a sterile environment, mechanical stimulation, and optical monitoring for the in vitro maturation of a tissue-engineered heart valve. With the camera module attached, tissue-engineered valves can be observed during the entire in vitro phase. This setting helps to find the optimal dynamic conditions for tissue-engineered heart valves to mature by adjusting flow and pressure conditions to provide physiological opening and closing behavior of the heart valve construct.