Nanoengineered Hydrogel Scaffolds for Enhanced Maturation and Functionality of hiPSC-derived Cardiac Tissues

Cardiovascular diseases (CVDs), including myocardial infarction (MI), are the major cause of death globally. Considerable research has been devoted in recent years to developing in vitro cardiac tissue models utilizing human induced pluripotent stem cells (hiPSCs) for regenerative medicine, disease modeling, and drug discovery applications. Notably, electroconductive hydrogel scaffolds have shown great promise in the development of functional hiPSC-derived cardiac tissues for both in vitro and in vivo cardiac research. However, the underlying mechanism(s) by which these nanoparticles contribute to the function and fate of stem cell-derived cardiac tissues have not been fully investigated. To address these knowledge gaps, this Ph.D. dissertation focuses on the mechanistic analysis of the impact of nanoengineered electroconductive hydrogel scaffolds on 2D and 3D hiPSC-derived cardiac tissues. Specifically, within the first phase of the project, hydrogel scaffolds were nanoengineered using either electroconductive or non-conductive nanoparticles to dissect the role of electroconductivity features of gold nanorods (GNRs) in the functionality of isogenic 2D hiPSC-derived cardiac patches. Extensive biological and electrophysiological assessments revealed that, while biophysical cues from the presence of nanoparticles could potentially play a role in cardiac tissue development, electroconductivity cues played a major role in enhancing the functional maturation of hiPSC-derived cardiac tissues in 2D cell-seeded cardiac patches. This dissertation further describes the application of GNRs in developing a biomimetic 3D electroconductive Heart-on-a-chip (eHOC) model. The 3D eHOC model was then leveraged to comprehensively investigate the cellular and molecular responses of isogenic human cardiac tissues to the electroconductive microenvironment through single-cell RNA sequencing (scRNAseq), an aspect not addressed in previous studies. The enhanced functional maturation of the 3D eHOC was demonstrated through extensive tissue-level and molecular-level assays. It was revealed that the GNR-based electroconductive microenvironment contributes to cardiac tissue development through the enrichment of calcium handling and cardiac contractile pathways.Overall, these findings offer additional insights into the role of electroconductive hydrogel scaffolds in regulating the functionalities of hiPSC-derived cardiac tissues. Furthermore, the proposed 3D eHOC platform could also serve as a more physiologically representative model of the in vivo microenvironment for in vitro applications, such as drug testing and disease modeling studies.