Cell-Free Layer Measurements in a Network with Bifurcating Microchannels Using a Global Approach

Abstract

One of the most interesting hemodynamic phenomenon observed in microchannels is the existence of a marginal cell-free layer (CFL) at regions adjacent to the wall. This is a well known phenomenon that occurs in simple glass capillaries and in vivo microvessels, but has never been investigated in detail in biomedical microdevices containing complex geometries. In the present chapter, in vitro blood flowing through bifurcating microchannels was studied, with the aim of characterizing the cell-free layer (CFL). For that three different videos with different hematocrit and flow rates were considered. All images were obtained by means of a high-speed video microscopy system and then processed in MatLab using the Image Processing toolbox. The numerical data was obtained automatically and analyzed by optimization techniques using the genetic algorithm approach. The results suggest that the CFL were formed in a similar way at the upper and lower regions in all bifurcations.

Cell-free layer analysis in a polydimethysiloxane microchannel: a global approach

“…A genetic algorithm was used to solve the constrained optimisation problem and the best fit was obtained by using the function (g 3 ), i.e., a sum of trigonometric functions. This finding corroborates the results obtained by Taboada et al (2013) and Bento et al (2015) and where they have performed similar studies in microchannels networks and have found that the function (g 3 ) is the one that best fit to their CFL measurements. As a future work, we will test other functions and examine a bigger variety of physiological fluids used in vitro blood studies.…”

“…Individuals with less value have a high probability of being selected whereas the new generation of individuals may have a minor objective value than the previous generation. The evolution process is repeated until the stopping criterion is satisfied (Bento et al, 2013(Bento et al, , 2015Catlin et al, 2011;Kumar et al, 2010). In this work it was implemented the genetic algorithm proposed by Bento et al (2013Bento et al ( , 2015 using Matlab software.…”

“…In recent years, optimisation algorithms have become increasingly robust and as a result several researchers have applied this methodology to study phenomena happening in microfluidic devices. For instance, Bento et al (2015) have measured the CFL in a network containing multiple bifurcations and confluences and they have shown that the function that best fits the CFL was the sum of trigonometric functions.…”