现有技术体系下的新药研发周期需要数十年，研发经费需要数十亿美元，成功上市的比例仅有万分之一左右，其主要的原因就是药效学、毒理学评价很大一部分内容是观察动物对药物的响应，而药物在临床上的治疗对象是人体。建立一种可以模拟人体器官的体外模型，对候选药物进行快速的活性筛选和毒性评价，可以有效降低药物研发成本和提高成功率，国际上自2010年开始器官芯片出现在了人们的视野里。目前器官芯片可以从“组成”、“结构”和“环境”等多面对人体器官进行模拟，已经逐步成为进行药效学、毒理学和药代动力学研究的新平台。壳寡糖是氨基葡萄糖通过β-1，4糖苷键连接形成的2-8的低度聚合糖。壳寡糖因其生理作用的多样性和特异性而备受关注；对提高免疫力、抑制肿瘤生长、促进肠道有益菌群生长、改善肠炎等有显著地效果。为进一步探究壳寡糖对人体肝肿瘤细胞转移和肠屏障的调控作用，本文分别构建了体外三维肿瘤转移模型和蠕动大肠模型，并对模型的功能进行了深入评价和优化。之后利用肿瘤转移模型，探究了乙酰度46 %壳寡糖（paCOS）对肝肿瘤细胞转移的抑制作用，发现paCOS对肝肿瘤细胞的转移的不同阶段都有显著的抑制作用（已申请专利）。利用体外肠炎病理模型，探究了特定聚合度壳寡糖在肠炎发生发展过程中对肠粘液屏障、肠上皮屏障和炎症反应的调控作用。论文第一部分构建了一个新的肿瘤-血管微流控芯片模型，利用该模型我们第一次在体外实现了肿瘤转移不同阶段（增殖、迁移、侵入血管和黏附于血管）的模拟。此外，我们发现带动态流体的“血管”对肝肿瘤细胞（HepG2）和乳腺癌细胞（MDA-MB-231）转移都有显著的影响，同时发现肿瘤细胞迁移的方向与血管血流的方向一致。利用该肿瘤模型我们发现乳腺癌细胞（MDA-MB-231）对血管内皮层胞间连接蛋白有显著的破坏作用，主要从胞间侵袭进入血管；肝癌细胞（HepG2）则可以通过破坏基底膜穿过血管内皮细胞进入血管腔。与传统的静态模型对比，利用该动态微流控肿瘤转移模型，研究发现5-氟尿嘧啶对肿瘤细胞转移不同阶段均有显著的抑制作用。初步结果显示，此微流体装置可用于研究不同肿瘤细胞在转移过程中的不同生理现象，同时也可以作为一个抗肿瘤药物筛选平台用于药物毒性评价和精准医疗。论文第二部分我们通过酶解法制备了一种乙酰度为46 %的壳寡糖（paCOS），利用体外肿瘤转移模型，我们发现paCOS通过体外动态血管吸收具有显著抑制肝癌细胞（HepG2）增殖的活性，同时可以通过抑制肝肿瘤细胞伪足的形成来抑制HepG2细胞迁移。此外, paCOS在10 μg/mL对肝肿瘤细胞侵袭进入血管腔的抑制作用要强于100μg/mL，可能是在100μg/mL时paCOS对肿瘤血管增殖和屏障功能有破坏作用。在连续动态处理3小时后，paCOS可显著减少粘附于血管内皮层表面的肝肿瘤细胞数量。因此，我们的研究结果发现，paCOS具有较高的抗肝肿瘤转移的潜力，可进一步开发抗肿瘤转移的新药物。论文第三部分我们构建了一款全新的肠-血管微流体系统并用于肠道微生物与宿主互作研究。通过压力泵驱动我们实现了肠腔蠕动模拟。观察发现肠上皮细胞在蠕动条件下与血管内皮细胞共培养5天即可分化出致密屏障和吸收功能（而传统静态模型需要培养21天）。同时，可观察到肠上皮细胞分泌出粘液层糖链和微绒毛。利用该模型，我们发现干酪乳杆菌可以显著减少大肠杆菌侵袭引起的肠屏障损伤和炎症反应，同时可以实现微生物与肠上皮细胞稳定共培养一周。研究表明，此体外肠器官芯片模型可以用于研究肠道微生物与宿主相互作用，同时也可用于药物对肠炎等疾病的活性评价和机制研究。论文第四部分我们首次使用肠器官芯片模型探究了低分子量壳寡糖对肠屏障损伤和炎症反应的的调控机制。通过构建DSS肠炎损伤模型，我们发现一种壳寡糖（RX-14）可以通过促进肠上皮细胞生长和促进黏液层糖链表达减轻肠上皮损伤。之后通过构建大肠杆菌侵袭炎症模型，我们发现在动态条件下，RX-14壳寡糖可以显著降低大肠杆菌的粘附量和侵入血管腔的量，对肠上皮屏障和血管内皮屏障都有显著的保护作用。通过检测肠腔和血管腔炎症因子的表达量，我们发现RX-14壳寡糖可以显著降低炎症反应。此外我们发现RX-14壳寡糖可以减少肠上皮细胞toll样受体（TLR）蛋白表达，减少NF-κB (p65)蛋白的核DNA结合率。这些结果可总结出RX-14壳寡糖可以通过促进黏液层分泌、促进肠上皮细胞增殖减轻肠炎引起的屏障损伤，可以通过NF-κB信号通路减轻炎症反应。本文设计并构建了体外肿瘤转移模型，实现体外肿瘤细胞增殖、迁移、侵袭入血管和粘附于血管腔的肿瘤转移过程模拟；同时构建了蠕动肠模型实现了体外肠蠕动、肠屏障吸收功能和肠黏液层的模拟。利用肝肿瘤转移模型，探究并证明了部分乙酰化壳寡糖（paCOS）可以穿过血管内皮细胞抑制肝肿瘤细胞增殖、迁移，同时在低浓度下对保护血管内皮、抑制肿瘤细胞侵袭入血有更显著的作用。利用DSS和大肠杆菌侵袭肠炎模型，探究并证明了RX-14壳寡糖可以通过促进肠上皮黏液层的糖链合成保护黏液层和肠上皮屏障，同时通过可以减NF-κB (p65)蛋白的核DNA结合率降低炎症反应。综上，该肿瘤转移模型和蠕动肠模型可以用于相关药物的活性筛选和作用机制研究；乙酰度为46%的壳寡糖（paCOS）可以为肝肿瘤细胞转移治疗提供支持；聚合度2-8的RX-14壳寡糖可以为肠炎修复提供更多的治疗方案。;The new drug development cycle under the existing technology system requires more than several decades, and the R & D expenditure needs more than billions of dollars. The successful market rate is only about 1 in 10,000. The main reason is that the pharmacodynamics and toxicological evaluation are very large. Part of the content is to observe the animal's response to the drug, but the clinical treatment object of the drug is the human body. Establishment of an in vitro model that can simulate the human body to perform a rapid round of active screening of drug candidates and eliminate most of the ineffective drug candidates has become a hot spot for scientific researchers to chase. And then the organ on a chip model appeared in people's vision. Organ chips can be used to simulate human organs from "composition", "structure" and "environment". It has become a new platform for pharmacodynamics, toxicology and pharmacokinetic research.Chitooligosaccharides (COS), as a low-grade polymeric sugar, are generally made up of 2-10 monosaccharides connected by glycosidic bonds. COS has attracted much attention due to the diversity and specificity of its physiological effects, it has significant effects on improving immunity, inhibiting tumor growth, promoting the growth of beneficial bacteria in the intestine and improving enteritis. In order to further explore the effect and mechanism of COS on liver tumor cells and intestinal barrier, this dissertation constructs a three-dimensional tumor metastasis models and a peristaltic large intestine models in vitro, and evaluates the functions of the models firstly. Later, using the tumor metastasis model, we explored the inhibitory effect of COS with a degree of acetylation of 46% (paCOS) on liver tumor cells metastasis, and found that paCOS significantly inhibited different stages of liver tumor cells metastasis. Using an in vitro enteritis pathological model, we explores the effect of low-polymerization COS on the intestinal mucus barrier, intestinal epithelial barrier, and inflammatory response during the development of enteritis.In the first part of the dissertation, a novel microfluidic tumor-vessel co-culture system was established to reproduce the different phases of cancer metastasis (proliferation, migration, intravasation and adherence) individually in vitro for the first time. It was observed that blood vessels with fluid flow had big impact on metastasis of liver cancer cells HepG2 and breast ones . In particular, it was found that both HepG2 and MDA-MB-231 cells migrated in the direction of “blood flow”. Furthermore, MDA-MB-231 cells invaded through paracellular mode disrupting the intercellular endothelial junctions, whereas HepG2 cells engaged in transcellular intravasation through transcellular process. Compared with traditional assays, much more potent inhibition of 5-fluorouracil (5-Fu) on different phases of tumor metastasis was observed on the microsystem. In summary, the microfluidic device yielded abundant information about each phase of tumor metastasis, and would provide a powerful platform for use in drug screening, toxicology studies, and personalized medicine in future.In the second part of the dissertation, a dynamic tumor-vessel microsystem undergoing physiological flow was leveraged. paCOS (FA0.46) significantly inhibited proliferation of HepG2 cells through vascular absorption on the chip, and inhibited migration of HepG2 cells by inhibiting the formation of pseudopod in liver tumor cells. It was also found that paCOS at 10 μg/mL had a stronger inhibitory effect on liver tumor cells invading blood vessels than that of paCOS at 100 μg/mL, and paCOS at 100 μg/mL, which had a significant destructive effect on tumor vascular growth and barrier function. Moreover, paCOS reduced the number of liver tumor cells adhering onto the surface of HUVECs layer after 3 hr of treatment. Therefore, the results revealed that paCOS had considerable potential as drugs for anti-tumor metastasis. In the third part of the dissertation, a novel human gut-vessel microfluidic system was established to study the host–microbial interaction. Peristaltic motion of the cells on the chip was driven by a pneumatic pump. When intestinal epithelial cells (Caco2) were co-cultured with vascular endothelial cells (HUVECs) on the peristaltic microfluidic chip, Caco2 showed normal barrier and absorption functions after 5 days cultivation, which generally took 21 days in static Transwell models. Intestinal microvilli and glycocalyx layer were seen after 4 days cultivation, and Lactobacillus casei was successfully co-cultured for a week in the intestinal cavity. A model for intestinal damage and inflammatory responses caused by E. coli was set up on this chip, which were successfully suppressed by Lactobacillus casei or antibiotic. In summary, this human gut-vessel microfluidic system showed a good potential for investigating the host–microbial interaction and the effect and mechanism of microbiome on intestinal diseases in vitro.In the fourth part of the dissertation, we used a human gut on a chip models to explore the regulatory mechanism of low molecular weight chitooligosaccharides on intestinal barrier injury and inflammatory response. By constructing an in vitro DSS intestinal injury model on the human gut chip, we found that COS can reduce intestinal epithelial injury by promoting the growth of intestinal epithelial cells and promoting the expression of mucous layer. Then, by constructing an E. coli enteritis model on the intestinal chip, we found that under dynamic (Fluid flow plus peristalsis) conditions, COS can significantly reduce the amount of E. coli adhesion and invasion into the vascular cavity, and have a significant protective effect on the intestinal epithelial barrier and vascular endothelial barrier. Besides, COS can significantly reduce inflammatory response by reducing the expression of toll-like receptor (TLR) protein and reducing the nuclear DNA binding rate of NF-κB (p65) protein. These results can be concluded that COS can reduce barrier damage caused by enteritis by promoting secretion of mucous layer, and reducing inflammatory response through NF-κB signaling pathway.In this paper, an in vitro tumor metastasis model is designed and constructed, which can simulate the whole process of tumor metastasis in vitro. Using a liver tumor metastasis model, we have explored and proved that paCOS with FA 0.46 can pass through vascular endothelial cells to inhibit the proliferation and migration of liver tumor cells. At the same time, it has a more significant effect on protecting vascular endothelial cells and inhibiting tumor cells invading into the blood at low concentrations. In addition, we designed and constructed a peristaltic human gut model in vitro, and realized the simulation of intestinal peristalsis, intestinal barrier and absorption function, intestinal mucus layer expression. By utilizing DSS and E. coli invasion enteritis model, we explored and proved that low molecular weight COS can protect the mucus layer and intestinal epithelial barrier by promoting the expression of sugar chains in the intestinal epithelial mucus layer, and at the same time it can reduce inflammatory response by inhibiting the nuclear DNA binding rate of NF-κB (p65) protein. In summary, the tumor metastasis model and the peristaltic human gut model can be used for the screening of related drugs and the studing of drug action mechanism. paCOS with an acetylation degree of 46% can provide support for the treatment of liver tumor cells metastasis. COS with a degree of 2-8 polymerization can provide more treatment options for enteritis repair.Key Words: Chitooligosaccharide, Organ on a chip, Tumor metastasis model, Peristaltic gut-vessel model