Overflow Microfluidic Networks for Open and Closed Cell Cultures on Chip

IBM Research-Zurich, Saumerstrasse 4, 8803 Ruschlikon, Switzerland.
Analytical Chemistry (Impact Factor: 5.83). 04/2010; 82(9):3936-42. DOI: 10.1021/ac100771r
Source: PubMed

ABSTRACT Microfluidics have a huge potential in biomedical research, in particular for studying interactions among cell populations that are involved in complex diseases. Here, we present "overflow" microfluidic networks (oMFNs) for depositing, culturing, and studying cell populations, which are plated in a few microliters of cell suspensions in one or several open cell chambers inside the chip and subsequently cultured for several days in vitro (DIV). After the cells have developed their phenotype, the oMFN is closed with a lid bearing microfluidic connections. The salient features of the chips are (1) overflow zones around the cell chambers for drawing excess liquid by capillarity from the chamber during sealing the oMFN with the lid, (2) flow paths from peripheral pumps to cell chambers and between cell chambers for interactive flow control, (3) transparent cell chambers coated with cell adhesion molecules, and (4) the possibility to remove the lid for staining and visualizing the cells after, for example, fixation. Here, we use a two-chamber oMFN to show the activation of purinergic receptors in microglia grown in one chamber, upon release of adenosine triphosphate (ATP) from astrocytes that are grown in another chamber and challenged with glutamate. These data validate oMFNs as being particularly relevant for studying primary cells and dissecting the specific intercellular pathways involved in neurodegenerative and neuroinflammatory brain diseases.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The use of soft lithography-based poly(dimethylsiloxane) (PDMS) valve systems is the dominating approach for high-density microscale fluidic control. Integrated systems enable complex flow control and large-scale integration, but lack modularity. In contrast, modular systems are attractive alternatives to integration because they can be tailored for different applications piecewise and without redesigning every element of the system. We present a method for reversibly coupling hard materials to soft lithography defined systems through self-aligning O-ring features thereby enabling easy interfacing of complex-valve-based systems with simpler detachable units. Using this scheme, we demonstrate the seamless interfacing of a PDMS-based fluid control module with hard polymer chips. In our system, 32 self-aligning O-ring features protruding from the PDMS fluid control module form chip-to-control module interconnections which are sealed by tightening four screws. The interconnection method is robust and supports complex fluidic operations in the reversibly attached passive chip. In addition, we developed a double-sided molding method for fabricating PDMS devices with integrated through-holes. The versatile system facilitates a wide range of applications due to the modular approach, where application specific passive chips can be readily attached to the flow control module.
    Journal of Micromechanics and Microengineering 03/2013; 23(5):055011. DOI:10.1088/0960-1317/23/5/055011 · 1.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Diffusion of autocrine and paracrine signaling molecules allows cells to communicate in the absence of physical contact. This chemical-based, long-range communication serves crucial roles in tissue function, activation of the immune system, and other physiological functions. Despite its importance, few in vitro methods to study cell-cell signaling through paracrine factors are available today. Here, we report the design and validation of a microfluidic platform that enables (i) soluble molecule-cell and/or (ii) cell-cell paracrine signaling. In the microfluidic platform, multiple cell populations can be introduced into parallel channels. The channels are separated by arrays of posts allowing diffusion of paracrine molecules between cell populations. A computational analysis was performed to aid design of the microfluidic platform. Specifically, it revealed that channel spacing affects both spatial and temporal distribution of signaling molecules, while the initial concentration of the signaling molecule mainly affects the concentration of the signaling molecules excreted by the cells. To validate the microfluidic platform, a model system composed of the signaling molecule lipopolysaccharide, mouse macrophages, and engineered human embryonic kidney cells was introduced into the platform. Upon diffusion from the first channel to the second channel, lipopolysaccharide activates the macrophages which begin to produce TNF-α. The TNF-α diffuses from the second channel to the third channel to stimulate the kidney cells, which express green fluorescent protein (GFP) in response. By increasing the initial lipopolysaccharide concentration an increase in fluorescent response was recorded, demonstrating the ability to quantify intercellular communication between 3D cellular constructs using the microfluidic platform reported here. Overall, these studies provide a detailed analysis on how concentration of the initial signaling molecules, spatiotemporal dynamics, and inter-channel spacing affect intercellular communication.
    Biomicrofluidics 07/2014; 8(4):044104. DOI:10.1063/1.4887098 · 3.77 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Microfluidic chips are a promising platform for the exploration of modern life science. In this review, we outline the functional features of microfluidic chips and recent developments in their applications in cell-based bioanalysis, and highlight the diversification of cell-based microfluidic chips, including animal, plant and microbial cell chips. Future prospects of microfluidic chips in cell-based bioanalysis are also discussed.
    Chinese Journal of Analytical Chemistry 01/2012; 40(1):24–31. DOI:10.1016/S1872-2040(11)60519-7 · 0.79 Impact Factor

Full-text (2 Sources)

Available from
Jun 3, 2014