Abstract

Microconfined Flow-based Imaging Methods to Study Red Blood Cell Deformability and Clustering in Vitro

Giovanna Tomaiuolo, Researcher, The University of Naples Federico II

In this work, we report on an in vitro systematic fluid dynamic investigation of RBC suspensions flowing in a microcirculation-mimicking silicon device containing a network of microchannels of diameter comparable to cell size. The microfluidics device is made of PDMS and is fabricated by using soft-lithography techniques. RBC membrane rheological behavior is investigated by analyzing the transient behavior of RBC shape in confined flow and by measuring the membrane viscoelastic properties in converging/diverging microchannels. The time scale of the transient process is independent on the applied pressure drop and the measured value for healthy cells is in agreement with previous micropipette data from the literature. In order to study the effect of reduced deformability of the RBC membrane, the flow behavior of glutaraldehyde (GA)-hardened RBCs has been also analyzed. The comprehension of the single cell behavior leaded to the analysis of the RBC flow-induced clustering. Cluster size and velocity is investigated as a function of the applied pressure drop and of the microcapillary residence time, including the effect of polydispersity. The main results of this work is the development of a novel methodology to estimate cell membrane viscoelastic properties. Possible applications include the analysis of RBC deformability in pathological situations, for which reliable quantitative methods are still lacking.