Bioinspired Microfluidic Assay for In Vitro Modeling of Leukocyte?CEndothelium Interactions
Authors: G. Lamberti, B. Prabhakarpandian, C. Garson, A. Smith, K. Pant, B. Wang, and M.F. Kiani. Anal.
Chem., 2014, 86 (16), pp 8344?C8351 DOI:10.1021/ac5018716

SynRAM microfluidic chips comprising of realistic microvascular networks were used to understａnd the role of classical inhibitors of individual steps of the leukocyte adhesion cascade. Experimental results matched very well with in vivo data highlighting the unique ability of the platform for real-time analysis of these dynamic events in a morphologically realistic environment (Lamberti et al 2014).

Rolling, adhesion, and migration of neutrophils in bMFA; migration of neutrophils (labeled with fluorescent dye) into the tissue compartment of bMFA after 120 min of continuous flow. (1 and 2) Solid arrows in the top right panels show a rolling neutrophil which (3) becomes adherent; dotted arrows in the top right panels show firmly adherent neutrophils. A neutrophil migrating from a vascular channel through the barrier into the tissue compartment over time (bottom right).

Neutrophil rolling using SynRAM microfluidic chips is similar to leukocyte rolling in vivo; Box and whisker plots summarizes the comparison of leukocytes rolling velocity measured in vivo and in SynRAM chips and shows no significant difference (p=0.758; Mann-Whitney Rank Sum Test). The ??+?? marked in the box indicates the mean.

Neutrophil adhesion in SynRAM microfluidic chips is similar to leukocyte adhesion in vivo; Distribution of the number of adhered leukocytes and neutrophils as a function of distance from the nearest bifurcation in vivo in mouse cremaster muscle model and in vitro in microfluidic chips, respectively. Both histograms are skewed to the left indicating that leukocytes and neutrophils preferentially adhere near bifurcations with the peak occurring at one vessel or channel diameter from the nearest bifurcation.

Antibody blocking of specific steps in the adhesion/migration cascade downregulates other steps of the cascade; Monoclonal antibodies against E-selectin (aE-selectin), ICAM-1(aICAM-1), and PI3K (wortmannin) significantly reduced the number of rolling, adhering, and migrating neutrophils in SynRAM microfluidic devices.

Antibody blocking of specific steps in the adhesion/migration cascade downregulates other steps of the cascade; monoclonal antibodies against E-selectin (aE-selectin), ICAM-1(aICAM-1), and PI3K (wortmannin) significantly reduced the number of rolling, adhering, and migrating neutrophils in bMFA. The numbers represent the percentage of activity after treating cells with the respective blockers in comparison to their corresponding control values (mean ?? SEM; N = 3).