Studies On Microfluidic Chip-based Cell Culture And Drug Inducing Apoptosis

The technology of microfluidic chip provides a suitable research platform for cell biology due to its micro scale, flexible composition and easy integration. Microfluidic chip has more advantages on cell research than macroscopic conventional research system in many aspects. Microfluidic chip which has the comparable scale with the blood issue can imitate the microenvironment in human body, integrate many operations on a chip simply and complete the high-throughput operation with micro scale, which saves plenty of time and sample. This thesis focuses on developing of a microfluidic chip system for human colorectal carcinoma cell CCL-187 culture and drug inducing apoptosis.Microfluidic chips were designed and fabricated by sealing a piece of glass and a polydimethyl-siloxane (PDMS) substrate with microchannels. The effects of different extracellular matrix treating the surface of the microchannel in microfluidic chip was studied, which influenced cell culturing and growing. Poly-L-Lysine (PLL) was used to treat the channels of the microchip to make cell attach to the material rapidly and dispersedly. Collagen, which was gained from the tails of rats, was coated on the surface of the channels in order to make cell attach to the channel surface for a long time. When combined application of the two extracellular matrix, it presented the complementary effect. Two kinds of modes was made use of to refresh the culture medium for the cells in the microchannel:a micro injection pump out of the culture incubator and a novel osmotic micro pump with continuous refreshing culture medium in the culture incubator. The advantages and disadvantages of the two modes were compared. Micro injection pump has a stable and accurate flow-rate with random regulation. On the other hand, the micro injection pump can be sterilized easily, while it cannot refresh culture medium continuously which makes operation become rather time-consuming and tedious. The osmotic micro pump holds the feature of being power-free, inexpensive and pulse-free, which suits cell culture. The osmotic micro pump can provide continuous perfusion of medium, and remove the waste which is unfavorable for cell attaching, and create a uniform microenvironment for cell growth. However, the osmotic micro pump cannot regulate the flow-rate randomly. Furthermore, it cannot keep a stable flow-rate due to the change of osmotic driving reagent concentration. Additionally, the osmotic micro-pump cannot be sterilized easily and completely, which increases the opportunity of cell bacterial infection.Furthermore, it was confirmed that the human colorectal carcinoma cells cultured on the microchip possess the original functions without variation by fluorescent antibody experiment.The microfluidic chips were also used in preliminary study on drug inducing apoptosis. The single drug 5-fluorouracil injection (5-Fu injection), arsenic trioxide injection(As2O3 injection) and combined drugs (5-Fu injection+As3O2 injection) was made use of to stimulate human colorectal carcinoma cells. The result indicated that the combined drugs can be more effective than the single drug, and the effects depend on the stimulating time. The research proved the possibility of high-throughput drug screen on the microfluidic chips.In this paper, the advantage and potential of microfluidic chip for cell research were proved by human colorectal carcinoma cell seeding, culturing, staining and drug stimulating.