Design, fabrication and optimization of a multifunctional microfluidic platform for single-cell analyses.

Laburpena

Cell handling is essential for research and application development in clinical diagnostics. In numerous biological assays thousands of cells are cultured without considering that the interaction between them may interfere in the resulting data. Nowadays, it is well known that individual cells, even those with identical appearance may display different phenotypes. These disparities make individual cells have different responses to equal stimulus in the same conditions. Therefore, single-cell studies provide more precise information, than average responses traditionally obtained from cell populations, and open new opportunities for drug discovery and personalized medicine. Microfluidics has emerged as a powerful enabling technology to investigate the natural complexity of cellular systems. Microfluidic channels have dimensions ranging from tens to hundreds of microns which are comparable to the size of a cell. This allows the realization of large numbers of biomedical studies with high spatial and temporal resolution. In addition, the microfluidic platforms have numerous advantages inherent to the micrometer scale, such as: minimized reagent consumption and waste production, high sensitivity and fast response or high integration capabilities. Overall, this is translated to versatile and cost-effective solutions. In this framework, this thesis presents a multidisciplinary approach for the development of microfluidic platforms capable of capturing, treating and/or analyzing single-cells with the corresponding added value. In order to achieve this, different microfluidic platforms have been designed using computer aided design (CAD) software. The manufacture and development of these microdevices have been carried out by means of microfabrication techniques such as photolithography and polymer micromolding processes. The fabricated microfluidic platforms have been structurally characterized and validated by means of profilometry and various microscopic techniques. In addition, theoretical (computational fluid dynamics simulations) and experimental fluid dynamics characterizations inside the microfluidic platform have been performed. Finally, the versatility of the devices has been highlighted through several cell-based assays including cell viability, cytotoxicity and cell migration studies accounting for healthy and cancer cells. As a result of this work, a multifunctional, low cost and high-throughput microfluidic platform has been devised. In particular, the trapping mechanism relies on hydrodynamic traps and the accurate and simple handling is based on the control of the laminar co-flow phenomenon. Thanks to its modular nature, different microstructures can be easily coupled to the main platform enabling cell migration and co-culture analyses. Overall, the developed microfluidic platform will facilitate a better understanding of key biological processes by providing well-controlled and versatile microenvironments