Acoustic driven flow and lattice Boltzmann simulations to study cell adhesion in biofunctionalized μ-fluidic channels with complex geometry

Abstract

Accurately mimicking the complexity of microvascular systems calls for a technology which can accommodate particularly small sample volumes while retaining a large degree of freedom in channel geometry and keeping the price considerably low to allow for high throughput experiments. Here, we demonstrate that the use of surface acoustic wave driven microfluidics systems successfully allows the study of the interrelation between melanoma cell adhesion, the matrix protein collagen type I, the blood clotting factor von Willebrand factor ͑vWF͒, and microfluidic channel geometry. The versatility of the tool presented enables us to examine cell adhesion under flow in straight and bifurcated microfluidic channels in the presence of different protein coatings. We show that the addition of vWF tremendously increases ͑up to tenfold͒ the adhesion of melanoma cells even under fairly low shear flow conditions. This effect is altered in the presence of bifurcated channels demonstrating the importance of an elaborate hydrodynamic analysis to differentiate between physical and biological effects. Therefore, computer simulations have been performed along with the experiments to reveal the entire flow profile in the channel. We conclude that a combination of theory and experiment will lead to a consistent explanation of cell adhesion, and will optimize the potential of microfluidic experiments to further unravel the relation between blood clotting factors, cell adhesion molecules, cancer cell spreading, and the hydrodynamic conditions in our microcirculatory system.

Controllable Acoustic Mixing of Fluids in Microchannels for the Fabrication of Therapeutic Nanoparticles

“…These findings on VWF-VWF-interaction under shear became possible due to broad range of tunable shear forces with such a hybrid reactor [ 21 ]. Moreover, for the interaction of VWF with melanoma cells and the matrix protein collagen type I, we also applied the open system based on hydrophilic tracks and SAW as a nanopump [ 22 ]. Within the last few years, we have developed a miniaturized (~100 μL) lab-on-a-chip hybrid system which allows for the quantification of cell adhesion under dynamic conditions which are comparable to those of physiological relevance.…”

Simulation of the Separated flow over a Wall-Mounted Hump using Finite-Volume Based Lattice Boltzmann Method

“…, , (5) where the term determines the spatial accuracy and by setting this term to 1/3 one can obtain second order accuracy.…”

“…ince its first introduction by McNamara 1 almost thirty years ago, the LBM has become an alternative to the classical Navier-Stokes (NS) equations based methods and its use and applications in various areas are getting increasingly accepted among the Computational Fluid Dynamics (CFD) community, see for example works of Thommes et al 2 , Li et al 3 , Chen et al 4 , and Fallah et al 5 . Derived from the Lattice-Gas Automata (LGA) method 6 , the LBM basically shares the same idea.…”

Surface Acoustic Wave Microfluidics

“…Schmid et al (2012) subsequently demonstrated a closed-circuit PDMS microchannel pump that circumvents these limitations (Figure 4c). The same racetrack loop was used several times in succession for microfluidic cell-cell, cell-particle, and cell-surface interaction studies (Fallah et al 2010, Fillafer et al 2009, Schneider et al 2008a and to invoke the shear stretching of the von Willebrand factor fibers discussed in Section 3.1. Liquid interfaces in coflowing laminar streams within a straight PDMS channel may also be manipulated by placing the IDTs transverse to the channel in a setup similar to that of Shi et al (2009b) and that depicted in Figure 2c, except employing traveling SAWs (Figure 4d ) (Franke et al 2010).…”