The increasing interest to establish significant correlations between blood cell mechanical measurements and
blood diseases, has led to the promotion of microfluidic devices as attractive clinical tools for potential use in
diagnosis. A multi-step microfluidic device able to separate red and white blood cells (RBCs and WBCs) from
plasma and simultaneously measure blood cells deformability (5 and 20% of hematocrit) is presented in this
paper. The device employs passive separation based on the cross-flow filtration principle, introduced at each
daughter channel. At the outlets, hyperbolic geometries allow single-cell deformability analysis. The device was
tested with blood from five healthy and fifteen diabetic type II voluntary donors. The results have shown that
WBCs have lower deformability than RBCs, and no significant differences were observed in WBCs from healthy and pathological blood samples. In contrast, RBCs have shown significant differences, with pathological cells exhibiting lower deformability. Shear rheology has shown that blood from patients with type II diabetes has higher viscosity than blood from healthy donors. This microfluidic device has demonstrated the ability to reduce cell concentration at the outlets down to 1%, an ideal cell concentration for assessing the blood cells deformability, under healthy and pathological conditions. The results provide new insights and quantitative information about the hemodynamics of in vitro type II diabetes mellitus RBCs. Thus, such device can be a promising complement in clinical diagnosis and biological research as part of an integrated blood-on-a-chip system.
This work was also supported by Fundação para a Ciência e a
Tecnologia (FCT) under the strategic grants UIDB/04077/2020 and
UIDB/00532/2020. D. Pinho and V. Faustino acknowledge the Ph.D.
scholarships SFRH/BD/89077/2012 and SFRH/BD/99696/2014,
respectively, both provided by FCT. Susana Catarino thanks FCT for her
contract funding provided through 2020.00215.CEECIND. F. T. Pinho is
thankful to FCT for financial support through projects LA/P/0045/2020
of the Associate Laboratory in Chemical Engineering (ALiCE) and projects UIDB/00532/2020 and UIDP/00532/2020 of Centro de Estudos de
Fenomenos de Transporte.
