Cell migration into scaffolds under co-culture conditions in a microfluidic platform

Abstract

Capillary morphogenesis is a complex cellular process that occurs in response to external stimuli. A number of assays have been used to study critical regulators of the process, but those assays are typically limited by the inability to control biochemical gradients and to obtain images on the single cell level. We have recently developed a new microfluidic platform that has the capability to control the biochemical and biomechanical forces within a three dimensional scaffold coupled with accessible image acquisition. Here, the developed platform is used to evaluate and quantify capillary growth and endothelial cell migration from an intact cell monolayer. We also evaluate the endothelial cell response when placed in co-culture with physiologically relevant cell types, including cancer cells and smooth muscle cells. This resulted in the following observations: cancer cells can either attract (MTLn3 cancer cell line) endothelial cells and induce capillary formation or have minimal effect (U87MG cancer cell line) while smooth muscle cells (10T 1/2) suppress endothelial activity. Results presented demonstrate the capabilities of this platform to study cellular morphogenesis both qualitatively and quantitatively while having the advantage of enhanced imaging and internal biological controls. Finally, the platform has numerous applications in the study of angiogenesis, or migration of other cell types including tumor cells, into a three-dimensional scaffold or across an endothelial layer under precisely controlled conditions of mechanical, biochemical and co-culture environments.

Integrating biological vasculature into a multi-organ-chip microsystem

“…A robust 4 day procedure applying pulsatile shear stress has been established to cover all fluid contact surfaces of the system with a functional, tightly closed layer of HDMECs. In contrast to the vertical plane HDMEC growth described in literature, 30,31 the entire coverage of our microvascular system with human ECs render possible biological haemocompatibility of such a microvascular system for the first time. The chip layout reduces the circulating fluid volume in the microvascular transport system down to 10 ml, at least two orders of magnitude lower than the circulation volume applied in any of the systems operated with external pumps and reservoirs.…”

“…Kamm and co-workers, for example, succeeded in culturing HDMECs in a vertical plane of microchannels and monitor capillary morphogenesis into collagen gels in the lateral plane. 30,31 In contrast to all other organs of the body, the skin of vertebrates needs to adapt rapidly to eventually changing external temperatures by immediate blood vessel contraction or relaxation. Moreover, the skin of carnivores is the organ with the most pronounced exposure to repeated injury, due to their aggressive life-style.…”

Characterization of the interaction between fibroblasts and tumor cells on a microfluidic co‐culture device

“…Therefore, it is of great importance to investigate the heterotypic cell interactions between tumor cells and fibroblasts. At present, co-culture is often used to investigate the interactions between heterotypic cells by using Transwell assay [9,10], in which two types of cells are separated into upper and lower chambers by a semi-permeable membrane, or by bathing cells in conditioned medium [11][12][13][14]. However, these assays are limited by the tedious manual operations which require several procedures, and they are all typical end-point assays, which are difficult to realize real-time observation.…”

“…Recently, several work has been reported to perform co-culture on microfluidic platform, including capillary morphogenesis [14]; macrophage cells invasion Abbreviations: ACC, adenoid cystic carcinoma; GES-1, gastric mucosa epithelia cell line; HepG-2, human liver carcinoma cell line; HFL-I, human embryonic lung fibroblast; PI, propidium iodide; a-SMA, a-smooth muscle actin…”

“…Recently, several work has been reported to perform co-culture on microfluidic platform, including capillary morphogenesis [14]; macrophage cells invasion [18], HeLa and HUVECs cells movements [13]. These work mainly focus on the investigation of single cellular process at a time which only provide limited information to characterize the biological events in cells.…”