Microfluidic Lab-On-Chip devices for exosomes detection

Exosomes Extracellular Vesicles (EEVs) have acquired great interest in biomedical field, due to their biological contents (such as proteins, mRNAs, miRNAs), which can make them potential biomarkers for early detection, diagnosis and treatment of cancer and other diseases. However, exosome isolation and detection for biomarkers analysis are challenging. In fact, the standard methods for exosomes analysis are time-consuming, costly, and require big laboratory instruments, so, the theranostic potential of exosomes is difficult to exploit. In the last decade, microfluidic platforms for exosome analysis have been developed, because at this dimensional scale it is possible to manipulate small amounts of sample volumes, to conduct separations and detections with high resolution, to reduce the laboratory analysis costs and, also, the time requested for the analysis. Therefore, there is a growing interest in microfluidic devices for exosomes analysis. In this thesis project, two microfluidic platforms have been designed and fabricated: a serpentine micromixer and V-shaped microchannels for biological material centrifugation. The serpentine mixer has been designed for exosomes capture, by performing an ELISA on-chip, which would use a specific antibody present on the exosomes surface, to capture them. To do this, the mixing process must be enhanced at the microfluidic scale, and a serpentine-shape channel was chosen. This platform has been, first tested with a Computational Fluid Dynamic (CFD) simulation, in order to give a first assessment of the mixing. Then, fabricated through replica molding and quantitatively validated through image analysis. The V-shaped microchannels have been fabricated through a lithographic process, and an impedance-based measurement system is proposed as a quantitative detection method. Proof-of-concept validation has been conducted with yeast samples. Both of these devices showed good performances with the samples used, stating that, these initial proof of concepts have been successful and, with the optimization of some processes, it will be possible to validate them with exosomes solutions. The two approaches followed and its respective prototypes are a first step in the development of a microfluidic-lab-on-chip device for the analysis of exosomes, with potential impact in the discovery of new biomarkers.