A Microfluidic System That Specifically Screens Bladder Cancer Cells From Circulating Tumor Cells

ObjectiveTo fabricate a microfluidic chip for specifically screening bladder cancer cells with the monoclonal antibody-BCMabl and Biotin-Avidin System.Methods1.The chip which was made of two layers was designed by the Autocad.The upper of the chip was fishbone structure while the bottom was the microchannel.2.The chip was fabricated through photolithography after spin coating negative photoresist,trimming,punching and cleaning process.3.The surface of the microchannel was modified by Biotin-Avidin—BCMab1-System(BAS).4.The preparation of sample solution:we take T24 bladder cancer cells as the samples.Before the experiment,the T24 bladder cancer cells was stained with a fluorescent dye 5(6)-carboxyl fluorescein diacetate)succinimide ester(CFDA SE).Then labeled cells were put into the blood that was diluted 10 times.Finally,different concentrations of sample liquid experiment were made according to the experiments.5.Chip grouping:in the experiment,to study whether the antibodies capture the target cells or not,we have divided the chip into two kinds:the one which has the fishbone structure and BCMabl antibody;the other one which has the fishbone structure without BCMab1 antibody.6.To test the chip:the samples were pumped into the two kinds of chips with the flow velocity of 100?l/min.The samples contain 5000 cells per ml.After that,the chip was washed by the PBS.Then we observed the results and did statistical analysis7.Exploring the factors influencing the chip capture target cells:The different concentration of T24 cells and different velocity were used to test the validity of the chips.In the experiment,the surfaces of the chips were designed to contain the fishbone structure or not.Then we tested the capture rate of the chip and observed the influence of flow rate,target cells and fishbone structure on the capture rate.Results1.The chip was consisted of two layers,whose size is 40mm x 5mm x3mm.The upper structure is the fishbone structure that changes the fluid flow state.The fishbone structure is 45?m high and the spacing between fishbone structure is 50?m.The lower structure that captures the circulating tumor cells is micro-channel whose height is 50 ?m.2.The chip coating with the antibody whose captured cells are(20.8 ±6.3)is better than one without the antibody whose captured cells are(1.2±1.1)(P<0.05).3.The cell's concentration had little impact on the trapping of target cells.With the increase of flow velocity,capture rate of chip would decrease.At the same flow rate,the chip with the fishbone structure whose capture rate is(90.3±1.0)%is better than one without the fishbone structure whose capture rate is(46.7±2.1)%(P<0.05).ConclusionsIn summary,this chip has characteristics of inexpensive,convenient and high capture rate.