Team:TU Eindhoven/Microfluidics/Introduction

Microfluidics: Introduction

A substantial part of the TU Eindhoven iGEM 2014 Project is Microfluidics. Microfluidics is a technique that comprises various fields of engineering. This technique operates on a micrometer scale and thus uses small volumes. For the encapsulation of bacterial cells, droplet-based microfluidics is used. As is extensively elaborated in the General Overview Page, the engineered bacteria must be brought into the proximity of PEG polymers. The final goal is to verify the intended function of a cell encapsulation device. To achieve this, three processes have to be accomplished:

1. Combining a PEG solution and a bacterial culture with our engineered E. coli bacteria. These are the essential substances to perform the click reaction. After combining, this is called the Water Phase.


2. The Water Phase has to be dispersed with an Oil Phase into droplets. This oil phase contains a fluorosurfactant in order to prevent aggregation and agglomeration of the droplets. It is crucial to form droplets with one cell in each droplet, since it will assure that each induvidual bacterial cell is encapsulated correctly – possible formation of a film is hereby avoided.


3. The result of the previous two processes is a droplet including PEG and engineered E. coli bacteria inside an oil phase. With a microfluidic feature (bumpy mixer) the droplet can be stirred. The droplets are collected in a chamber where the click reaction is initiated with the use of UV light.

Before these processes can be performed, certain questions have to be answered and certain research has to be done. For instance, how is it possible to form droplets? What is the optimal method to recollect the content of the droplets? And numerous of other questions that need answering for instance the required flow speed of the water and oil phase and the viscosities of the phases.

Figure 1. TU Eindhoven iGEM 2014 in a microfluidic device.

Bibliography

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[3] Mcdonald, J. Cooper, David C. Duffy, Janelle R. Anderson, Daniel T. Chiu, Hongkai Wu, Olivier J. A. Schueller, and George M. Whitesides. "Fabrication of microfluidic systems in poly(dimethylsiloxane)." Electrophoresis 21.1 (2000): 27-40.

[4] Mazutis, L., Gilbert, J., Ung. W.L., Weitz, D.A., Griffiths, A.D. & Heyman J.A. (2013). Single-cell analysis and sorting using droplet-based microfluidics. Nature, 8(5), pp. 870-91.

[5] Song H, Chen DL, Ismagilov RF. Reactions in droplets in microfluidic channels. Angew Chem Int Ed Engl. 2006;45:7336–7356.