Cardiovascular diseases (CVDs) are the leading cause of mortality worldwide, causing nearly 25% of deaths in the United States. Despite the efforts to create in vitro models for the study and treatment of CVDs, these are still limited in their recapitulation of the heart tissue. Thus, the engineering of accurate cardiac models is imperative to gain more understanding and improve the outcome of CVDs. This Ph.D. dissertation focuses on the development and characterization of isogenic cardiac organoids derived from human induced pluripotent stem cells (hiPSCs). Additionally, the integration of chemical and biological cues for enriching their microenvironment and promoting their maturation state and function were studied. First, hiPSC-derived cardiac cells were utilized for the fabrication of multicellular spherical microtissues, namely isogenic cardiac organoids. The cellular composition and culture time of the engineered tissues were optimized to induce cellular aggregation and the formation of cell-cell interactions. Also, ribbon-like gold nanoparticles, namely gold nanoribbons (AuNRs), were synthesized, characterized, and biofunctionalized for their integration into the isogenic cardiac organoids. In-depth biological evaluation of the organoids showed enhanced cardiac maturation markers. Furthermore, a supplement-free cell culture regime was designed and evaluated for fabricating isogenic cardiac organoids. Mechanistic, cellular, and molecular-level studies demonstrated that the presence of hiPSC-derived cardiac fibroblasts (hiPSC-CFs) significantly improves the morphology and gene expression profile of the organoids. Electrophysiological-relevant features of the organoids, such as conduction velocity (CV), were further investigated utilizing a microelectrode array (MEA) platform. It was shown that MEA offers a simple, yet powerful approach to assessing electrophysiological responses of the tissues, where a trend in decreased CV was found due to the presence of hiPSC-CFs. Overall, this dissertation has a broad impact casting light on the development strategy and biological mechanisms that govern the formation and function of isogenic cardiac organoids. Moreover, this study presents two unique approaches to promote maturation of stem cell-derived cardiac organoids: 1) through the integration of novel biofunctionalized nanomaterials, and 2) through a cell culture regime, leading to enhanced function of the organoids. The proposed micro-engineered organoids have broad applications as physiologically relevant tissues for drug discovery, CVDs modeling, and regenerative medicine.

Glioblastoma multiforme (GBM) is an aggressive brain cancer without effectivetreatment options, leaving patient survival rates extremely low. HDAC1 knockdown was found to initiate an invasive phenotype in vivo, particularly within the BT145 human glioma stem cell (hGSC) line. Analysis through RNA sequencing (RNA-seq) gene expression and regulatory networks found both CEBPβ, a known transcription factor (TF) involved in cellular invasion, and the STAT3 pathway, a notorious genetic component of GBM, were differentially expressed in BT145 hGSCs after HDAC1 knockdown. Furthermore, overlap of genes regulated by CEBPβ and STAT3 indicate the CEBPβ/STAT3 pathway may be involved in the observed BT145- specific invasive phenotype. The SYstems Genetics Network AnaLysis (SYGNAL) pipeline was applied to construct sex-specific gene regulatory networks from The Cancer Genome Atlas (TCGA) GBM patient expression data. Unique bicluster eigengenes were discovered separately for all, female, and male patients. Through the application of these bicluster eigengenes to a GBM cohort with multiparametric magnetic resonance imaging (mpMRI) localized biopsies, sex-specific associations between bicluster expression, mpMRI readout, and hallmarks of cancer were determined. Distinctive cancer functions were revealed transcriptionally through bicluster expression, and connected to a unique mpMRI feature. Specifically, SPGRC mpMRI indicated a strong signal for both immune hallmarks (evading immune detection and tumor-promoting inflammation). At the same time, MD mpMRI displayed a tendency toward sustained angiogenesis, possibly signaling the formation of new blood vessels. Uncovering each mpMRI feature’s underlying biological processes enables improved GBM diagnosis and treatment utilizing an individualized, non-invasive approach.