Studying Cell Metabolism and Cell Interactions Using Microfluidic Devices Coupled with Mass Spectrometry by Huibin Wei

Author:Huibin Wei
Language: eng
Format: epub
Publisher: Springer Berlin Heidelberg, Berlin, Heidelberg

3.2.2 Fabrication of Microfluidic Devices

The desired microstructures was produced by poly-dimethylsiloxane (PDMS) following the standard soft lithography techniques. Briefly, the mold used for generating microchips of cell culture and MEC were fabricated by spincoating the negative photoresist SU-8 2050, at 3,000 rpm (50 μm thick film) and 1,800 rpm (80 μm thick film) separately on silicon wafers which were prior cleaned by piranha solution. Then the master molds were exposed and developed following the lithography technique to transfer the designed patterns on the silicon wafers. The 10:1 premixed PDMS prepolymer was prepared, degassed, and poured on the mold, before placing in a 70°C oven for 2 h. The cured PDMS was removed from the mold with a surgical scalpel and then carefully peeled off. A flat-tip syringe needle was used to punched the channel inlets and outlets. The fabricated PDMS microchips were bonded on the cleaned glass slides by the oxygen plasma treatment for 90 s. The microchannels obtained for PC12 cell cultures were 1 mm wide, 15 mm long, and 50 μm deep, while the dimensions of the channels for the pretreatment MEC were 1 mm wide, 15 mm long, and 80 μm deep.

Figure 3.1shows the scheme of the integrated analysis platform. As described in the last chapter, the microfluidic device was connected with ESI ion source viaa PTFE tube. The microchannels sealed with the poly-L-lysine coated glass slides were employed for the PC12 cell cultures, while the channels sealed with normal glass slides were carried out for fabricating the pretreatment MEC. Firstly, the cells were cultured in channel 1 until they propagated to certain concentration. Then required chemicals were applied to the cells for a while, the cells secretion was collected and pretreated through channel 2. In the end, channel 2 was connected to the mass spectrometry to achieve the qualitive and quantitive analysis of the eluted compounds.

Fig. 3.1Illustration of integrated microfluidic devices combined with ESI-Q-TOF MS. (a) Schematic diagram of the analysis procedures: PC12 cells culture, secretion pretreatment, and detection by MS. (b) Scheme of the integration devices. (c) Image of the microfluidic device and MS. An enlarged viewof the microchip is shown on the right(Reproduced from Ref. [4], with permission from The Royal Society of Chemistry)

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