Mechanical stimulation is essential for chondrocyte metabolism and cartilage matrix deposition. In vitro, mechanical stimulation is accomplished via culture in a bioreactor. Traditional methods for evaluating the developing tissue are destructive, time consuming, and expensive. Nondestructive evaluation of engineered tissue is promising for the development of replacement tissues. Here, we present a novel instrumented bioreactor for dynamic mechanical stimulation and nondestructive evaluation of tissue mechanical properties and extracellular matrix (ECM) content. The bioreactor is instrumented with a video microscope, load cells in each well to measure tissue stiffness, and an ultrasonic transducer for evaluating ECM content. The objective of this study was to develop an instrumented bioreactor that could be utilized to adequately stimulate and nondestructively evaluate tissue engineered cartilage. Chondrocyte-laden hydrogels were placed in the bioreactor and subjected to dynamic intermittent compression at 1 Hz and 10 % strain for one hour twice per day for seven days. Compressive modulus of the constructs, measured online in the bioreactor and offline on a mechanical testing machine, did not significantly change over time. Sulfated glycosaminoglycan (sGAG) deposition increased significantly after 7 days, independent of loading. Further, reflection coefficient of the loaded construct decreased significantly after 7 days, consistent with an increase in sGAG content. This preliminary work with our novel bioreactor demonstrates its capabilities for dynamic culture and nondestructive evaluation.
Citation: Journal of Medical Devices
Pub Type: Journals
ultrasound, cartilage, glycosaminoglycan, compression, tissue engineering