Engineering microscale cellular niches for three-dimensional multicellular co-cultures

Abstract

Summary Modeling the in vivo microenvironment typically involves placing cells in a three-dimensional (3D) extracellular matrix (ECM) in physiologically relevant context with respect to other cells. The mechanical and chemical features of 3D microenvironments play important roles in tissue engineering, tumor growth and metastasis, and in defining stem cell niches, and it is increasingly recognized that cells behave much differently when surrounded by a 3D ECM than when anchored to a 2D substrate. To create microenvironments that more closely mimic in vivo settings, here we describe a novel microfluidic device that allows multiple discrete constructs of 3D cell-laden hydrogels to be patterned in a sequence of simple steps. The microfluidic platform allows for real time imaging of the interactions between multiple cell types exposed to both autocrine and paracrine signaling molecules, all within a 3D ECM environment. Detailed modeling determined that surface tension, hydrophobic interactions, and spatial geometry were important factors in containing the gels within distinct separate channels during the filling process. This allowed us to pattern multiple gel types side-by-side and pattern 3D gels spatially with tight dimensional control. Cells embedded in gels could be patterned by culturing MDA-MB-231 metastatic breast cancer cells and RAW 264.1 macrophage cells within distinct collagen type I and Matrigel ECM environments, respectively. Over a 7 day culture experiment, RAW cells invaded into neighboring gels containing MDA-MB-231 cells, but not into gels lacking cells. These studies demonstrate the versatility and potential of this new microfluidic platform to engineer 3D microscale architectures to investigate cell-cell and cell-matrix interactions.

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

“…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.…”

Diffusion of self-assembled monolayers of thiols on the gold surfaces covered with polydimethylsiloxane stamps

“…In recent years, SAMs found wide applications in chemistry, physics, and especial biology [2][3][4][5] when SAMs combined with microfluidic technology [6][7][8][9][10]; for example, we applied alkanethiolate SAMs on gold surface to study the relationship between the shape of mammalian cells and their migration direction [11]. Recently, when we applied alkanethiolate SAMs combined with microfluidic technology to establish interaction models for multiple types of cells [12], we found that the SAMs diffused on the surfaces of evaporation-coated gold slides which were covered with polydimethylsiloxan (PDMS) stamps [13].…”

A high-throughput microfluidic assay to study neurite response to growth factor gradients

“…The three PDMS posts (Fig. 1C) provide structural support to the gel and prevent gel from overflowing into the media channels prior to gel polymerization, via surface tension forces which dominate at these length scales 36 . Thus, in this configuration, the direction of neurite outgrowth is orthogonal to the direction of gradient, making this an effective setup to study neurite guidance.…”