Bridging the gap: Engineering a microfluidic device (Organ-On-a-Chip) as the next generation ’𝘪𝘯-𝘷𝘪𝘵𝘳𝘰’ model for breast cancer research

Abstract

Breast cancer remains a significant global health issue with the highest mortality rates among women, accounting for approximately 522,000 deaths worldwide annually. Incomplete understanding of initiation, progression, prevention, and treatment, coupled with challenges in drug discovery, creates a translational gap between research and clinical science. To address this, an engineered Organ-on-a-Chip (OOC) system is imperative, offering an alternative to animal testing. This research presents the Breast-on-a-Chip (BOC) system, which innovatively integrates multidisciplinary approaches to optimise microfluidic design, system integration, dynamic flow rate assessments, and consideration of the cell micro-environment. Within this thesis, the BOC system faithfully emulates the dynamic in-vivo micro-environment, offering a preferable alternative to animal and conventional models. This provides insights into early breast carcinogenesis, offering insights into how chemicals and lifestyle habits might induce metastasis in non-tumorigenic epithelial cell lines (MCF-12A). The BOC chamber’s optimised geometry and microfluidic chip design, determined via computational fluid dynamics (CFD) and bench-top experiments, resulted in a novel BOC with expanded operational volumes. The integrated system, featuring a bi-directional flow pump for media recirculation, enhances cell-cell interactions and signalling. Optimised valves and bubble traps ensure smooth operation. Bench-top experiments at 7, 15, & 30 μl/min identified the optimal flow rate, offering insights into acini size and flow-induced stresses. Designed for simplicity, the BOC accommodates one or multiple microfluidic chips, demonstrating co-culture potential. Preliminary experiments with breast epithelial, endothelial, and fibroblast cells on Matrigel hydrogel scaffolds indicate promising future endeavours. The exploration of a potential synthetic hydrogel, as an alternative to animal-derived hydrogels showed successful proliferation of MCF-12A cells. Viability assays and mechanical characterisation revealed a preference for harder PEGDMA scaffolds, with 87.7% and 91.0% cell proliferation achieved within 7 days. In conclusion, the extensive exploration and progress in the BOC system, including microfluidic design, hydrogel alternatives, and co-culture potential, significantly contribute to advancing OOC technology. These findings offer valuable insights into complex cellular micro-environments, laying a solid foundation for future research. The BOC integrated system emerges as a powerful tool for studying disease initiation and progression, especially in breast cancer research. As the OOC landscape evolves, this study’s contributions set the stage for more refined and focused investigations in the field.