Microfluidic Stem Cell Culture

Microfluidic stem cell culture Stem cell isolation Stem cell reprogramming Stem cell tissue engineering... 

Kim L, Vahey MD, Lee HY, Voldman J. Microfluidic arrays for logarithmically perfused embryonic stem cell culture. Lab Chip 2006 6 394-406. 

Keywords 3D cell cultures. Microenvironment, Microfluidics, Stem cells... 

Stem cell culture will in future become the source of cells for preliminary dmg screening, reducing the need for costly animal experiments [126, 127]. To address the problem of scalability, there is a need to perform tests on stem cells in a highly parallel fashion. Microfluidic devices offer this possibility, while limiting the amount of reagents and exercising precise control over the external cues. High-density microfluidic arrays with 24 x 24 cell chambers have been used for cell... 

Abstract Microfluidic devices offer a realistic environment for cell cultures as it is related to scales found in biological systems. The aim is to create more in vivo like systems, in comparison to 2D plate cultures. Creating 3D cell culture constructs increase the cell s functionality. By controlling the microenvironment (e.g., cell matrix, flow rate, temperature) cell functionality can be increased even more. As microfluidic devices allow for precise control of the microenvironment, they are a paramount tool to study stem cells and their differentiation caused by external factors. We will give an overview of the use of microfluidic devices for some biological problems, and especially as a cell culture platforms. We focus on 3D cell cultures and stem cells and their microenvironment. 

In this chapter, we will discuss the advantages for microfluidic devices as cell culture platforms. Then we will introduce 3D cell cultures as a way to overcome the limitations of the standard 2D cell culture methods, especially in microfluidic devices. Furthermore, we will show how to control the microenvironment inside the devices and how it affects cell cultures. Finally, apphcations in stem cell differentiation highlight the need of culture techniques and control inside the microfluidic devices. 

Fluid flow in microfluidic devices mimics vasculature in vivo [19], therefore the incorporation of fluid flow to cell cultures allows for efficient exchange of nutrients and metabolites between cells and culture medium, maintaining a constant cell culture microenviromnent [20, 21]. As such, cellular functions can be enhanced in microfluidic systems compared to conventional static cell cultures [17]. However, in microfluidic devices, fluid flow exerts shear stress (FSS), which can modulate cellular behaviour on the cells. FSS can induce the reorganization of the cytoskele-ton. Bone marrow stem cells (BMSCs) tend to align in the direction of the shear vector [22]. Furthermore, primary rat hepatocytes are known to be very sensitive to... 

Fig. 11 Overview of the possible uses for a multiplexed microfluidic cell culture system. Input can be used for control of the stem cell nice and drug testing. The gradient generator creates a concentration profile of the input factors. The cell culture chamber is a perfusion chamber. Analysis involves monitoring the output of the device, which can include imaging with appropriate biomarkers, analysis using Inline sensors or standard laboratory equipment [74]...

As has been mentioned in the section on 3D cell cultures (Sect. 4), soluble factors play an important part in cell functions, and in the case of stem cells, on the cell fate. Microfluidics can help to study the responses of stem cells towards the soluble factors in a precise controlled extracellular microenvironment. 

There is much hope that fundamental research into stem cell biology can eventually be translated into cell-based therapies to treat human disease. Stem cells possess the ability of selfreplication and can be expanded in culture. Stem cells can also be genetically modified and differentiated into aU of the cells comprising tissues that may 1 day be replaced or repaired via tissue-engineering applications. Rapid advances in materials chemistry, photolithography, microfabrication, and microfluidics have provided important new analytic approaches and have led to new insights into the physical chemistry of biological behavior at the subcellular and molecular levels [1]. 

Stem cells are immature, undifferentiated biological cells that can multiply to create exact copies of themselves, and also differentiate into the various specific cells that conprise different tissues such as skin, muscle, blood, or brain. This encyclopedia entry refers to recent applications developed to measure, culture (i. e., grow for expansion), and control stem cell function using microfluidic systems. Microfluidic flow environments present several advantages for the manipulation and study of stem cell behavior, including therapeutic applications that are currently in development. 

Several in vitro strategies for controlled differentiation of embryonic stem cells have been attempted previously. Cell-based therapies are limited by the difficulty in precisely controlling the behavior of stem cells in culture. The precise control of stem cell proliferation and differentiation in culture remains an unsolved problem. In static culture, the chemical composition of the microenvironment cannot be controlled over space and time. Microfluidic technology can help address this, by providing much better control over the cell microenvironment. In addition. 

Researchers have also built microfluidic devices for culturing adherent stem cells while simultaneously exposing those cells to a logarithmically varying range of flow rates... 

Khademhosseini et al. [8] have successfully cultured murine embryonic stem cells in a microfluidic array of reversibly sealed channels. These authors have proposed to position microwells 100 p,m apart using standard soft-lithography techniques, leaving sufficient room to overlay individual microchannels addressing each pattern. Thus, the total required area per microwell would... 

Large-Scale Expansion of Human Pluripotent Stem Cells. 37-10 Stirred Culture Vessels Rotary Cell Culture Systems Microfluidic Culture Systems... 

Villa-Diaz, L. G., Torisawa, Y. S., Uchida, T. et al. 2009. Microfluidic culture of single human embryonic stem cell colonies. Lab Chip 9 1749-55. 

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