Graduation Semester and Year
Spring 2026
Language
English
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Materials Science and Engineering
Department
Materials Science and Engineering
First Advisor
Dr. Kyungsuk Yum
Abstract
The mechanical properties of three-dimensional (3D) bioprinted constructs critically determine cellular behavior, including viability, proliferation, and morphology. Matching the mechanical properties of engineered tissue constructs to the diverse landscape of native tissues remains a central challenge in biofabrication, as tuning stiffness to mimic the extracellular matrix (ECM) often compromises printability. This dissertation presents a modular platform that utilizes the triblock copolymer poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) (PEO−PPO−PEO) as a universal fugitive carrier to decouple extrusion rheology from the final constructs’ mechanical properties. By employing microbial transglutaminase (mTG), a biocompatible enzyme that catalyzes covalent protein cross-linking, we established a “soft spectrum” (≤6 kPa) of gelatin-based bioinks. Stiffness was precisely tuned by varying mTG concentration and crosslinking duration without compromising cytocompatibility, covering a range of the soft mechanical environments. To address stiffer physiological environments, we developed a “stiff spectrum” (up to 24 kPa) using a dual-crosslinked gelatin methacryloyl (GelMA)/gelatin hydrogel system that combines enzymatic and photo-crosslinking. Mechanical characterization confirmed that the construct stiffness is adjustable over a physiologically relevant range, from ultra-soft neural analogs to rigid pre-calcified bone and fibrotic tissue analogs. Biological evaluation using encapsulated NIH 3T3 fibroblasts confirmed high cytocompatibility, with viability maintained above 90% across all crosslinking conditions. Cells exhibited stiffness-dependent spreading behavior, validating the platforms’ ability to guide cellular responses through mechanotransductive signaling. These results demonstrate that integrating enzymatic mTG crosslinking and dual crosslinking within a fugitive carrier system offers a versatile, reproducible, and controllable approach to engineering 3D bioprinted tissues, with significant implications for mechanobiology research and regenerative medicine.
License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Davuluri, Aneela, "Controlling Mechanical Properties of 3D Bioprinted Structures by Enzymatic Crosslinking" (2026). Material Science and Engineering Dissertations. 1.
https://mavmatrix.uta.edu/materialscieng_dissertations2/1