Mechanical loading is an important cue for directing stem cell fate and engineered tissue formation in vitro. Stem cells cultured on 2-dimensional (D) substrates and in 3D scaffolds have been shown to differentiate toward bone, tendon, cartilage, ligament, and skeletal muscle lineages depending on their exposure to mechanical stimuli. To apply this mechanical stimulus in vitro, mechanical bioreactors are needed. However, current bioreactor systems are challenged by their high cost, limited ability for customization, and lack of force measurement capabilities. We demonstrate the use of 3-dimensional printing (3DP) technology to design and fabricate a low-cost custom bioreactor system that can be used to apply controlled mechanical stimuli to cells in culture and measure the mechanical properties of small soft tissues. The results of our in vitro studies and mechanical evaluations show that 3DP technology is feasible as a platform for developing a low-cost, customizable, and multifunctional mechanical bioreactor system. • 3DP technology was used to print a multifunctional bioreactor system/tensile load frame for a fraction of the cost of commercial systems. • The system mechanically stimulated cells in culture and evaluated the mechanical properties of soft tissues. • This system is easily customizable and can be used to evaluate multiple types of soft tissues.
Keywords: 3D printing; 3DP, 3-dimensional printing; ABS, acrylonitrile butadiene styrene; CAD, computer-aided design; D, dimensional; DAPI, 4’,6-diamidino-2-phenylindole; DAQ, data acquisition device; DMEM, Dulbecco’s Modified Eagle’s Medium; Design and fabrication of a 3D printed mechanical bioreactor system and small-scale tensile load frame; FBS, fetal bovine serum; MSC-constructs, MSC-seeded collagen sponges; MSCs, mesenchymal stem cells; MTTFs, mouse tail tendon fascicles; Mechanical bioreactor; Mechanobiology; NI, National Instruments; PBS, phosphate buffered saline; Soft tissue biomechanics; Stem cells; Tissue engineering.