Application Of Multi-functional Microfluidic Chips To Research Of Suspension Cell Communication

On the basis of microfluidics, a serial of microfluidic chips were developed forthe research of suspension cells. These microfluidic chips could be used to preciselymanipulate cells and control cell environment at single cell and multiple cell levels.The microdevices provided novel platforms, opened new avenue for cell biologyresearch and contributed to breaking the bottleneck of biology research. Following arethe main contents and results of the thesis:(1) On the basis of sandbag structures developed by our lab, the design of cellimmobilization structures was improved. In one chip, a single cell array, containingapproximate600single Jurkat cells, could be formed for eight-channel detections inparallel. The responses of calcium-release activated Ca2+channels to activator andinhibitor were recorded and analyzed at a single Jurkat cell level. A large number ofdata from Jurakt cells were obtained from the single cell array. The variation of theCRAC channel response was observed. Although the variation of the CRAC channelresponse was caused by the heterogeneity of single cells, the average values of50single cells could reflect the effects of inhibitors at high concentrations. These resultsdemonstrated that our microfluidic chip could provide a platform for themulti-channel studies of the heterogeneity of calcium channel responses.(2) A microfluidic microdevice was developed to exert mechanical stimulationon a single suspension cell for mechanosensation research. In this microfluidic chip,an interesting single cell could be selected from a population, and subsequentlytrapped. Mechanical stimulation could then be exerted on the trapped cell. Using thischip, the mechanosensation of HL60cells (leukemic cells) were studied. We foundthat mechanical stimulation could trigger extracellular calcium to flow into HL60cells through channels on cell membranes. The cytoskeleton was not prerequisite forthe mechanosensation of HL60cells. Additionally, two function units were integratedin one chip for mechanosensation stduy in parallel. HL60cells (leukemic cells) and Jurkat cells (lymphocytes) both responded to mechanical stimulation. The resultsdemonstrated that the developed microfluidic device could be applied to investigatethe mechanosensation at a single suspension cell level and provided an opportunityfor high-throughput studies.(3) Cell immobilization structure, cell entrapment component, cell compressivecomponent and microvalves were integrated in one microfluidic chip. In thismicrofluidic chip, suspension cell-cell communication could be real-time monitored.Using the chip,the influence of different factors, including fluid states (static orflowing) and mechanical stimulation modes (single or persistent), were evaluated.Additionally, calcium oscillations were observed in a part of receipt cells when asmall number (10or31) of cells were exerted by mechanical stimulation.