Inertial Focusing of Cells Nuclei in Straight Microchannels

Need for highly pure sample of isolated cellular nuclei is drastically increased due to arise of new studies on cell apoptosis or genetic recombination. Common techniques for cell membrane lysing and nuclei isolation, although considerable, strongly depend on samples volumes, environment conditions and user experience. For this reason, there is a strong need for new devices that can automatically process samples, to isolate nuclei even from small volumes of cells. In this context, microfluidics has shown to be an excellent tool for cell sorting in continuous flow, thus likely applicable to subcellular entities. In particular, inertial microfluidic shows outstanding capabilities in this specific field, because it is able to provide a size-based isolation of highly pure samples, without need of any cell surface markers. Hence, this project aims to provide an essential investigation on inertial microfluidic flow behavior of isolated nuclei in a straight channel as a fundamental study for development of a continuous flow devices for nuclei isolation and complete subcellular sorting. Isolated nuclei size distribution revealed that they can be modeled as 4 and 7 µm diameter particles that represent the minimum and the mean value of the distribution respectively. Investigation of nuclei focusing behavior was performed in a PDMS microchannel at different flow rates and compared with behaviors of both particle sizes. Results showed that nuclei tent to migrate towards a single centered band similarly to 7 µm particles.