Tissue engineering promises to revolutionize treatment of connective tissue disease and injury. Tissue engineers can generate collagenous matrices but they are typically unable to bear in vivo loads. It has been shown that application of mechanical load to living collagenous matrics results in the improvement of mechanical properties and organization. The tissue is theorized to reorganize under tensile load in order to compensate for the force applied to it. Currently bioreactors capable of applying a mechanical load are being developed for large connective tissue however, nothing is developed for cornea or other small tissue specimens. Small tissue or cornea is highly organized and load bearing however there is no comparable device. The basis of our project is to design a miniature bioreactor capable of applying mechanical loads and resulting in organized cornea development. The cornea will be housed saturated environment while controlling strain and load. The bioreactor must measure the force applied to plus/minus0.01 N and the displacement to 1% of its overall length (0-200 micrometers). Cornea will be used in testing with dimensions of 2-4 mm length, by 8-20 mm length and only 50 microns thick. The specimen must be completely saturated in a sterile, anticorrosive visible environment at body temperature. A requirement was added later in the semester which included a 3 mm distance between specimen and outside environment. The requirement lead to a sliding quartz glass tubing design as seen in Figure 1. The quartz glass slides up to load specimen and is compressed down to seal container maintaining a 3 mm distance and a visible specimen. Copper block were used to heat chamber and pre heat tubing with the entering circulating fluid. Heat transfer analysis confirms the specimen will be heated to 37 degrees Celsius in 80 seconds. A zaber screw actuator was used to apply a force and measure displacement and a submersible load cell was used to measure the amount of force applied. The following summary states the requirements needed, design and components selected, as well as thermal and mechanical analysis completed.
connective tissue disease and injury, miniture bioreactor
Northeastern University, Department of Mechanical and Industrial Engineering
Cahill, Ryan; Church, Kelli; and Jaworski, Brad, "Collagen Bioreactor" (2007). Capstone Design Program: Mechanical Engineering. Paper 16. http://hdl.handle.net/2047/d10011341
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