Peptide-Mediated Selective Adhesion of Smooth Muscle and Endothelial Cells in Microfluidic Shear Flow

Abstract

Microfluidic devices have recently emerged as effective tools for cell separation compared to traditional techniques. These devices offer the advantages of small sample volumes, low cost, and high purity. Adhesion-based separation of cells from heterogeneous suspensions can be achieved by taking advantage of specific ligand-receptor interactions. The peptide sequences Arg-Glu-Asp-Val (REDV) and Val-Ala-Pro-Gly (VAPG) are known to bind preferentially to endothelial cells (ECs) and smooth muscle cells (SMCs), respectively. This article examines the roles of REDV and VAPG and fluid shear stress in achieving selective capture of ECs and SMCs in microfluidic devices. The adhesion of ECs in REDV-coated devices and SMCs in VAPG-coated devices increases significantly compared to that of the nontargeted cells with decreasing shear stress. Furthermore, the adhesion of these cells is shown to be independent of whether these cells flow through the devices as suspensions of only one cell type or as a heterogeneous suspension containing ECs, SMCs, and fibroblasts. Whereas the overall adhesion of cells in the devices is determined mainly by shear stress, the selectivity of adhesion depends on the type of peptide and on the device surface as well as on the shear stress.

Label-free, microfluidic separation and enrichment of human breast cancer cells by adhesion difference

“…7 These cell sorting systems have been miniaturized to microfluidic devices, demonstrating the possibility of being integrated into lab-on-a-chip devices. 8,9 In contrast, label-free methods typically utilize differences in physical properties such as cell size, 10 density, 11 cell adhesion, [12][13][14][15] and dielectric properties. [16][17][18] One potential drawback in label-free methods is that the physical difference is not high enough for efficient separation in many cases, which limits the widespread use of the label-free methods.…”

“…Currently, most cell separation and enrichment methods such as cell affinity chromatography (CAC) utilize immunoreactions to enhance the adhesion of one cell type than those of the other cell types. [12][13][14][15] It is noted in this regard that the cell adhesion is also modified on a nanostructured surface without specific proteins; it could be increased or decreased depending on the material and geometry used to construct the surface structure. [19][20][21] Recently, extensive efforts have been made to understand/control cell adhesions on various surface nanostructures using conventional or unconventional lithographic techniques.…”

Lectin-functionalized microchannels for characterizing pluripotent cells and early differentiation

“…15 Microfluidic device design and fabrication followed previously described soft lithography techniques. 16,17 Negative masters for device fabrication were manufactured at the George J. Kostas Nanoscale Technology and Manufacturing Polydimethysiloxane (PDMS) replicas were generated using silicone elastomer and curing agents in the ratio of 10:1 (w/w). This mixture was poured onto the negative master and allowed to degas, then cured at 65 C for 2 h. PDMS replicas were released from the wafers prior to punching inlet and outlet holes with a 19-gauge blunt-nose needle.…”

“…16 Briefly, a 4% (v/v) solution of 3-mercaptopropyl trimethoxysilane in ethanol was prepared under nitrogen atmosphere and injected into each device. This was left to react for 30 min and the unreacted silane was flushed out with ethanol and a 0.28% GMBS in ethanol solution flowed through the devices.…”

“…This channel geometry generates a linear decay in shear stress from inlet to outlet along the channel axis, a flow pattern known as Hele-Shaw flow. 16 By functionalizing the channel surfaces with different ligands, shear-mediated cell adhesion measurements along the axis can therefore be obtained for a fixed ligand surface density. The lectins DBA, PNA, and UEA I that recognize the sugars GalNAc, D-(þ)-galactose, and a (1,2)-fucose, respectively, and antibodies against the stem cell markers SSEA3, SSEA4, and CXCR4 were immobilized within Hele-Shaw devices to examine ES and DE adhesion profiles.…”