Bioreactor Design Optimization for Mechanical Stretch and Noninvasive Imaging

Researchers have developed in vitro bioreactor systems that can more closely simulate the native in vivo cell environment. These systems allow better understanding of the complex interactions between cells and their environment, and can lead to the development of more physiologically relevant engineered tissues. A novel bioreactor was previously created in our lab to subject up to four individual cellular constructs at a time to mechanical stretch, while allowing the ability to perform nondestructive imaging throughout the course of experiments. The goal of this project was to improve the design of the cell culture chambers, facilitating an extended duration of experiments and the multiplexing of simultaneous experimental groups. Validation studies were carried out to four weeks of mechanical stimulation, surpassing the ten days published with the previous system. Silk yarn constructs were seeded with MSCs and broken into three experimental groups according to duration. Each group contained four stretched constructs and four static controls. Confocal imaging throughout the process tracked cell growth and mechanical failure testing at the endpoints confirmed the changes in the biomaterial properties. The stretching was not shown to yield statistically significant differences in material properties, but time was a significant factor. The results show that the system is capable of long-term experiments, and may easily be adapted to vary experimental conditions.