High-throughput combinatorial cell co-culture using microfluidics

Abstract

Co-culture strategies are foundational in cell biology. These systems, which serve as mimics of in vivo tissue niches, are typically poorly defined in terms of cell ratios, local cues and supportive cell-cell interactions. In the stem cell niche, the ability to screen cell-cell interactions and identify local supportive microenvironments has a broad range of applications in transplantation, tissue engineering and wound healing. We present a microfluidic platform for the high-throughput generation of hydrogel microbeads for cell co-culture. Encapsulation of different cell populations in microgels was achieved by introducing in a microfluidic device two streams of distinct cell suspensions, emulsifying the mixed suspension, and gelling the precursor droplets. The cellular composition in the microgels was controlled by varying the volumetric flow rates of the corresponding streams. We demonstrate one of the applications of the microfluidic method by co-encapsulating factor-dependent and responsive blood progenitor cell lines (MBA2 and M07e cells, respectively) at varying ratios, and show that in-bead paracrine secretion can modulate the viability of the factor dependent cells. Furthermore, we show the application of the method as a tool to screen the impact of specific growth factors on a primary human heterogeneous cell population. Co-encapsulation of IL-3 secreting MBA2 cells with umbilical cord blood cells revealed differential sub-population responsiveness to paracrine signals (CD14+ cells were particularly responsive to locally delivered IL-3). This microfluidic co-culture platform should enable high throughput screening of cell co-culture conditions, leading to new strategies to manipulate cell fate.

Controlled Synthesis of Cell-Laden Microgels by Radical-Free Gelation in Droplet Microfluidics

“…We assume that the cell viability increases with the cell density due to intensified paracrine signaling: 54,55 Since the mobility of rhodamine 6G as a model molecule is reduced by the presence of the microgel matrix, we expect that other, similarly sized molecules such as growth factors, which regulate cell survival and proliferation, may also exhibit a reduced mobility as compared to that in a nongelly environment. A higher cell density may thus compensate for this reduced mobility and allow cells to chemically communicate more easily.…”

High throughput generation and trapping of individual agarose microgel using microfluidic approach

“…Kumachev et al (2011) showed a T-junction microfluidic device used for generation cell encapsulated agarose micro-beads with variable elasticity. Tumarkin et al (2011) presented a microfluidic platform for the high-throughput generation of hydrogel micro-beads for cell co-culture. These researches have revealed the potential of droplet-based microfluidics for preparation of agarose microgels in subsequent biological applications.…”

An automated system for high-throughput generation and optimization of microdroplets

“…6 For example, hydrogel microdroplets have been used as a building block for macroscale tissue generation 7 and a high-throughput platform for co-culturing cells. 8 Among several microdroplet fabrication methods, the most widely used method is the microfluidics-based method due to its high controllability of droplets, high throughput, low fabrication cost, and relatively simple device fabrication process. 9 There are three different methods to continuously generate microdroplets using the microfluidic devices: T-junction, flow-focusing, and co-axial flow methods.…”

“…The diameter of droplets is a key indicator of the size of droplets and has been widely used to characterize droplet generation mechanism. 8,10,14,15,19 The two most common methods to measure the diameter of droplets are optical sensing and electrical sensing. The electrical sensing is a low-cost, scalable method and uses the electrical property difference between aqueous and oil phase to detect the diameter of droplets.…”