In this study, we created self-assembled smooth muscle cell (SMC) tissue rings (comprised entirely of cells and cell-derived matrix; CDM) and compared their structure and material properties with tissue rings created from SMC-seeded fibrin or collagen gels. All tissue rings were cultured statically for 7 days in supplemented growth medium (with ε-amino caproic acid, ascorbic acid, and insulin-transferrin-selenium), prior to uniaxial tensile testing and histology. Self-assembled CDM rings exhibited ultimate tensile strength and stiffness values that were two-fold higher than fibrin gel and collagen gel rings. Tensile testing of CDM, fibrin gel and collagen gel rings treated with deionized water to lyse cells showed little to no change in mechanical properties relative to untreated ring samples, indicating that the ECM dominates the measured ring mechanics. In addition, CDM rings cultured in supplemented growth medium were significantly stronger than CDM rings cultured in standard, unsupplemented growth medium. These results illustrate the potential utility of self-assembled cell rings as model CDM constructs for tissue engineering and biomechanical analysis of ECM material properties.

Current alignment of transtibial prostheses is based on the prosthetist's subjective opinion and on trial and error fittings. The adaptors used to align prostheses are inexact, time-consuming to operate, and do not allow height adjustment. The primary objectives of this design project were to 1) develop an alignment adaptor that allows a prosthetist to quickly and effectively align the device based on a patient's gait and stance, and 2) provide the ability to quantify the patient's specific alignment. Using computer aided design (CAD), finite element analysis (FEA), and computer aided manufacturing (CAM), a new alignment adaptor was designed and manufactured using a novel pin configuration that allows for independent height adjustment. The prototype will be tested in a prosthetist's office using two AMTI AccuSway force platforms to measure the forces, moments, and center of pressure distributions during stance and gait. Results will be used to compare three situations on each patient: no alignment, alignment with gold standard device, and alignment with new prototype. Additionally, surveys will be conducted of the prosthetist and patient to obtain qualitative feedback. The design is innovative in its quantization and height adjustment, and results of the testing are expected to show improvement over current adaptors.