| In modern medical diagnosis,the use of portable instruments for point of care medical detection is an important development trend,and the performance of the detection depends on the concentration of the sample.Therefore,it is important to develop a low-cost,highly integrated and automated portable concentration instrument.This thesis designed a highthroughput ultra-high concentrated microfluidic concentration chip combining with inertial microfluidic technology and a handheld microfluidic concentration instrument combining the application of a shut-off valve.Specific research results are as follows:(1)Design and optimization of the high-throughput and high-fold enrichment chips based on inertial microfluidics was studied in this thesis.We proposed a three-layer spiral channel inner particle migration filter chip.Through the coupling of spiral channel inertial focusing and crossflow filtering,we achieved high reduction fold of cell concentration.The optimal concentration chip was determined through the optimization of the structure of the system.Combined with the thin-film chip manufacturing process,the cost of the chip was reduced.The chip was used to concentrate tumor cell samples sorted by the tumor cell separation instrument(MCF-7)and large-volume white blood cell samples(WBCs).We obtained the tumor cell recovery rate of85.45 ± 12.38% and a concentration fold of 10.68 ± 1.55.We obtained a concentration fold of1085.47 ± 99.47 was obtained by continuous concentration.(2)The further improvement of the concentration rate and processing throughput of the concentration chip was studied in this thesis.We designed a two-stage ultra-high reduction fold concentration chip combining the serially connected of inner cross-flow filtering chip and asymmetric sinusoidal concentration chip.In order to ensure the concentration performance,we matched the flow resistance and flow rate between the two stages.We obtained the cells recovery fold of more than 40.03 ± 2.56 at a recovery rate of more than 87.40 ± 6.24%.On the basis of single-core chips,a multi-core integrated microfluidic concentration chip was designed and manufactured.This chip greatly improved the throughput and shorting time required for sample processing(16 m L/min).The concentration fold of the chip was increased to 1349.83 ±142.82 through two concentration operations.In addition,We applied the chip to the enrichment of pleural / peritoneal effusion in cancer patients.The average concentration of tumor cells in the effusion was 34.92 ± 11.25.Our chip shorted the time of counting the number of cells,distinguishing the species and distinguishing the morphology in the pleural / peritoneal effusion,and provides a simple pre-treatment method for the clinical diagnosis of tumor.(3)The liquid circuit control system combined with integrated shut-off valve was studied,and we developed the handheld concentration instrument.Through the study of the principle and performance of the shut-off valve,the optimal structure of the shut-off valve suitable for the control environment of the instrument was determined.The liquid control unit of the instrument was integrated into the chip,which reduced the size of the instrument and made the control more automated.We designed three operation modes of the instrument to meet the application of different concentration objects,which made up for the shortcomings of the concentration chip and improved the concentration performance of the instrument: through the re-concentration mode,the concentration fold of the instrument is increased to 1321.67 ±221.21;through the waste liquid recovery mode,the recovery rate of the instrument was increased to 98.50 ± 0.16%.In order to reduce the cost,we used 3D printing materials to build the instrument.We applied concentration instrument to the clinical effusion of cancer patients and algae concentration,which provides more convenience for the analysis and diagnosis of cancer cases,and also brings more economic value. |
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