Date of Award
Master of Science (MS)
This thesis comprises two studies involving design and application of soft material systems. The goal of the first study was to design, fabricate, and characterize hydrogel lattice structures with consistent, controllable, anisotropic mechanical properties. Lattices, based on four types of unit cells (cubic, diamond, vintile, and Weaire-Phelan), were printed using stereolithography (SLA) of polyethylene glycol diacrylate (PEGDA). In order to create structural anisotropy in the lattices, unit cell design files were scaled in one direction by a factor of two in each layer and then printed. The mechanical properties of the scaled lattices were measured in shear and compression and compared to those of the unscaled lattices. For shear deformation in unscaled lattices, the apparent shear moduli were similar in the two orthogonal, testing directions. In contrast, scaled lattices exhibit clear differences in apparent shear moduli. In compression of unscaled lattices, apparent Young’s moduli were independent of direction in cubic and vintile lattices; in diamond lattices apparent Young’s moduli differed in the build direction, but were similar in the other two directions. Scaled lattices in compression exhibited additional differences in apparent Young’s moduli in the scaled and unscaled directions. Notably, the effects of scaling on apparent modulus differed between each lattice type (cubic, diamond, vintile, or Weaire-Phelan) and deformation mode (shear or compression). Scaling of 3D-printed, hydrogel lattices may be harnessed to create tunable, structures of desired shape, stiffness, and mechanical anisotropy, in both shear and compression. In the second study, acoustofluidic technology was used to rapidly develop 3D cell aggregates of tunable size and cell density. The efficiency and accuracy of cell manipulation were influenced by the interdigital transducers (IDTs) and microfluidic channel design; however, further work is required to improve immobilization results. In addition, a 3-layer tumor-on-a-chip (ToC) platform was developed to improve loading capabilities and allowed for radial, organoid growth. The trials conducted confirmed the ability of microvasculature to support tumor growth and angiogenesis when loaded in tandem. By incorporating these two processes and loading acoustically-formed, patient-derived organoids with fine-tuned properties into the 3-layer ToC platform, a reliable, repeatable, and eloquent method to study cancer biology can be established.
Phlip Bayly, Mark Meacham
Phlip Bayly Mark Meacham Alexandria Rutz
Available for download on Tuesday, April 23, 2024
Acoustics, Dynamics, and Controls Commons, Biology and Biomimetic Materials Commons, Biomechanical Engineering Commons