A Pillar-Free Diffusion Device for Studying Chemotaxis on Supported Lipid Bilayers.

Jia Hao,Jeong Min Oh,Keyue Shen,Winfield Zhao

doi:10.3390/mi12101254

Abstract

Chemotactic cell migration plays a crucial role in physiological and pathophysiological processes. In tissues, cells can migrate not only through extracellular matrix (ECM), but also along stromal cell surfaces via membrane-bound receptor–ligand interactions to fulfill critical functions. However, there remains a lack of models recapitulating chemotactic migration mediated through membrane-bound interactions. Here, using micro-milling, we engineered a multichannel diffusion device that incorporates a chemoattractant gradient and a supported lipid bilayer (SLB) tethered with membrane-bound factors that mimics stromal cell membranes. The chemoattractant channels are separated by hydrogel barriers from SLB in the cell loading channel, which enable precise control of timing and profile of the chemokine gradients applied on cells interacting with SLB. The hydrogel barriers are formed in pillar-free channels through a liquid pinning process, which eliminates complex cleanroom-based fabrications and distortion of chemoattractant gradient by pillars in typical microfluidic hydrogel barrier designs. As a proof-of-concept, we formed an SLB tethered with ICAM-1, and demonstrated its lateral mobility and different migratory behavior of Jurkat T cells on it from those on immobilized ICAM-1, under a gradient of chemokine CXCL12. Our platform can thus be widely used to investigate membrane-bound chemotaxis such as in cancer, immune, and stem cells.

Highlights

Cell migration plays a crucial role in physiological and pathophysiological processes, such as tissue regeneration [1,2], immunosurveillance [3,4], and cancer metastasis [5,6,7].During cell migration, cells typically respond to a gradient of chemoattractants, and migrate through the extracellular matrix (ECM)
Cancer cells often lodge in the microvasculature in distant organs and transmigrate through the endothelium via direct cell–cell adhesion to form micrometastases [12,13]
Two hydrogel barriers were permeable to chemoattractants but not cells, allowing for independent handling of lipid bilayer formation and cell loading from the gradient generation (Figure 1C)

Summary

Introduction

Cell migration plays a crucial role in physiological and pathophysiological processes, such as tissue regeneration [1,2], immunosurveillance [3,4], and cancer metastasis [5,6,7].During cell migration, cells typically respond to a gradient of chemoattractants, and migrate through the extracellular matrix (ECM). Cell migration plays a crucial role in physiological and pathophysiological processes, such as tissue regeneration [1,2], immunosurveillance [3,4], and cancer metastasis [5,6,7]. Cells can migrate along the surfaces of surrounding stromal cells in tissue microenvironments through membrane-bound receptor–. T cells exit and return to the blood circulation through T cell interactions with vascular/lymphatic endothelial cells [10]. They migrate over the surface of antigen presenting cells and other somatic cells in search for pathogenic antigens [11]. It is important to understand chemotaxis in the context of membrane-bound interactions

Methods

Results

Conclusion