A Microfluidic-Based Arteriolar Network Model for Biophysical and Bioanalytical Investigations

Dario Carugo, Lorenzo Capretto, Eric Nehru, Mohamed Mansour, Neil Smyth, Neil Bressloff, Xunli Zhang

Abstract

The microcirculation plays a key role in the delivery of essential substrates for oxidative processes in cells, the removal of products of cell metabolism, and the regulation of peripheral blood flow distribution. The functional properties of microvascular networks strongly depend on the rheological properties of blood and on the heterogeneity of their architecture. However, studying blood flow behaviour through in vivo microvascular systems is limited by ethical, economical and technical issues. Such limitations have opened the way to in vitro models, such as straight microcapillaries or network- like microchannel constructs, but current in vitro models present simplifications in the architecture design which result in the impossibility of faithfully reproducing key features of the in vivo microvascular haemodynamics. In the present study we report the development of a microfluidic-based in vitro model of the human arteriolar system, characterised by circular channel cross-section, network asymmetry and the presence of both bifurcation- and side-branches. The developed microdevice allows for the quantification of the velocity fields, cell-depletion layer thickness and haematocrit distribution within biomimetic microchannel networks. Results show the potential of our in vitro model in reproducing key features of blood flow behaviour which have been detected for microvascular systems in vivo, including the relationships between cell-depletion layer thickness, haematocrit and vessel diameter. The developed microdevices can find extensive applications in biological and biophysical research, where the mimicking of flow dynamics at the microcirculatory level is required.

Keywords: Arterioles, Cell-depletion layer (CDL), Haemodynamics, Microcirculation, Microfluidics, Network, Red blood cell (RBC)

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