3D printing and compression testing of biomimetic structures

2018-01-19The following thesis outlines the results of a series of studies on the mechanical properties of tissue samples in comparison to three dimensional (3D) printed silicone structures. The mechanical behavior of tissue is hard to study due to the lack of standardization of testing methods. Tissue also undergoes physical changes after extraction, which alter the properties of the samples. Accurate modeling of tissue samples has the potential to provide an easier path to greater understanding of tissue structure. This would lead to more accurate disease modeling through benchtop testing of biomimetic samples, resulting in more enhanced treatments. ❧ The primary 3D printing process utilized during this project is called projection microstereolithography. This is used to create a hollow shell of the simplified, modeled tissue structure. Silicone is then injected into the shell, which, in turn, is dissolved away once the silicone has cured. This leaves the finished structure, which is ready for compression testing. ❧ Testing the compressive properties of tissue yields significant information about the sample. The goal of this project was to be able to mimic these tissue tests with corresponding fabricated samples. This was achieved by compressing six varied structures. The first was the base model, comprised of a patterned XX structure, which was modified to create varied samples with induced defects. From the initial model, other structures were created by removing either one or two trusses in varying locations. The samples were then tested at three different strains, 10%, 20%, and 30%, to look at the effect of different load conditions on the buckling point of the sample. ❧ Being able to accurately reflect the properties of various tissues using synthetic models will help standardize the mechanical testing of biological material and provide an accurate structure for future biological study. Synthetic models would eliminate the time constraints of tissue testing, as well as the sensitivity to contamination. They could also provide cheaper models for testing the effect of various treatments on the body. Furthermore, additional coordination between biological and mechanical technology would aid in the advancement of tissue research