Erythrocyte fouling on micro-engineered membranes

Abstract

Crossflow microfiltration of plasma from blood through microsieves in a microchannel is potentially useful in many biomedical applications, including clinically as a wearable water removal device under development by the authors. We report experiments that correlate filtration rates, transmembrane pressures (TMP) and shear rates during filtration through a microscopically high channel bounded by a low intrinsic resistance photolithographically-produced porous semiconductor membrane. These experiments allowed observation of erythrocyte behavior at the filtering surface and showed how their unique deformability properties dominated filtration resistance. At low filtration rates (corresponding to low TMP), they rolled along the filter surface, but at higher filtration rates (corresponding to higher TMP), they anchored themselves to the filter membrane, forming a self-assembled, incomplete monolayer. The incompleteness of the layer was an essential feature of the monolayer's ability to support sustainable filtration. Maximum steady-state filtration flux was a function of wall shear rate, as predicted by conventional crossflow filtration theory, but, contrary to theories based on convective diffusion, showed weak dependence of filtration on erythrocyte concentration. Post-filtration scanning electron micrographs revealed significant capture and deformation of erythrocytes in all filter pores in the range 0.25 to 2 μm diameter. We report filtration rates through these filters and describe a largely unrecognized mechanism that allows stable filtration in the presence of substantial cell layers.

Conformational changes influence clogging behavior of micrometer-sized microgels in idealized multiple constrictions

“…The effect of different pore entrance angles can be seen as a link to the ‘membranes of the future’ that may have uniform pores, of which the actual geometry can be used to tune separation characteristics. Other example of areas that can benefit from our results are chromatography, injectable microgels for tissue engineering 26 and studies on blood cell flow 27 .…”

Estimation of Red Cell Filterability Using Two-Step Nickel Mesh Filtration System: A Feasibility Study of Tandem Filtration

“…Certain numbers of rigid cells are presumably trapped by the filter 1 in our two-step filtration. Red cell behaviors at the filter membrane surface depend on the perfusion pressure and pore size, i.e., deformable red cells dominate the pore resistance, whereas rigid cells roll and hesitate on the surface of filter membrane and then plug the pores 13) .…”

Advances in Microfluidics for Single Red Blood Cell Analysis

“…This is further proceeded with experiments to characterize the impact of filtration rates, transmembrane pressure, and shear rates to the dynamics of erythrocytes during the filtration process. It is found that erythrocytes tend to roll under low shear while settling under high filtration rates [273]. In one example, a microfluidic filtration platform with integrated rotary and bidirectional micro-pump has been used to separate WBCs from the whole blood with high efficiencies [262].…”