Modelling Strategy for the Characterization and Prediction of IIFK-Based Hydrogel Stiffness for Cell Culture Applications

Abstract

Due to the similar nature 3D synthetics share with in vivo cell conditions, peptide-based hydrogels pose an attractive strategy for the culturing of stem cells. One aspect of this unique cell culturing technique is the tunability of the hydrogel’s stiffness, a quality linked to stem cell differentiation. Due to this linkage, a methodology in which specific cell lineages are achieved within IIFK hydrogel cultures is proposed. This work provides an analysis for the peptide scaffold IIFK; it characterizes the effect between different peptide and PBS concentrations over the resulting hydrogel stiffness and develops a mathematical model to further elucidate this interaction. Nine different hydrogel formulations were made (with a minimum of eleven replicates each) and each of its replicate’s stiffness (storage modulus, Pa) was measured through rheological experiments. Then, two different methods of replicate selection were conducted and various models were derived, each using either of the two replicate selection methods and incorporating a specific number of replicates in their creation. Regardless of sample selection and replicate number, the generated models show extremely high significances between IIFK hydrogel stiffness and PBS concentrations over the resulting hydrogel stiffness. Data analysis shows that for IIFK, the hydrogel stiffness bears a strong behavior that can be modeled by a full quadratic equation. However, the data also shows that the dependency of the model is strongly correlated with the datasets chosen to produce it, with number of replicates and replicate values both resulting in differences in each model’s predictive reliability (e.g., 82% vs 91%). Therefore, while this thesis demonstrates the ability to model IIFK hydrogel behaviour with high predictability ratings, it also establishes the necessity of both producing more replicates as well as selecting the best values for IIFK-based hydrogel modelling.