微流控芯片和氧化石墨烯在乙型肝炎检测与预防中的应用研究

发布时间：2018-08-03 16:17

【摘要】：乙型肝炎病毒（Hepatitis B virus, HBV）的感染不仅可引起急、慢性病毒性肝炎（Acute and chronic hepatitis），而且还与肝硬化（Liver cirrhosis, LC）和原发性肝细胞癌（Hepatocellularcarcinoma, HCC）的发生、发展密切相关。我国是HBV感染的高发区，目前我国HBV感染者约有9300万人，其中慢性乙型肝炎患者约2000万人。乙型肝炎病毒可分为A到J共10个基因型，我国以B、C基因型占优势。基因型差异不仅影响e抗原的血清学转换、前C区启动子和前C区的突变位点、疾病的发展进程，还与抗病毒疗效有关。基因分型诊断有助于临床医生针对患者制定个体化的治疗方案。为了克服目前HBV基因分型法存在的检测时间长、灵敏度低、特异性差等缺点，我们将微流控芯片、巨磁阻传感器、磁性纳米团簇、环介导等温扩增（Loopmediatedisothermal amplification, LAMP）以及线性探针杂交技术相结合，建立了一种快速区分中国HBV优势基因型B和C的微流控芯片检测方法，，它集样品混合、核酸扩增和信号采集等多功能于一体，具有检测时间短、灵敏度高、特异性以及抗干扰能力强等优点。本论文首先建立了一种集成巨磁阻传感器、微流控芯片、磁性纳米团簇、PCR扩增和核酸杂交于一体的乙型肝炎病毒基因分型检测方法。172nm左右的磁性纳米团簇表面修饰有链霉亲和素，可与“PCR产物——核酸探针”杂交复合物末端的生物素发生特异性结合，GMR传感器可对停留其表面的磁性纳米团簇进行检测，检测灵敏度初步达到200IU·mL-1（103copies·mL-1）。随后，又对该检测方法进行了优化升级：我们将环介导等温扩增技术集成在微流控芯片中，进行核酸样品的高效扩增。同时，GMR传感器不再集成在微流控芯片中，而是作为独立检测器以供重复使用。最终可在一小时内实现最低10copies·mL-1HBV DNA的基因分型检测。此后，为了在微流控芯片上实现核酸扩增前核酸样本与反应试剂的快速高效混合，我们基于仿生学的原理，设计了一种由高深宽比的直通道单元与高宽深比的圆形室单元重复交替相连而成的微混合器。此外，为了评估氧化石墨烯作为HBV疫苗免疫佐剂的可能性，我们通过体外细胞实验分别研究了氧化石墨烯（Grapheneoxide,GO）和经过PVP修饰的氧化石墨烯（PVP-GO）对树突状细胞、T淋巴细胞、巨噬细胞等主要免疫细胞的影响。结果表明，氧化石墨烯经PVP修饰后，其免疫学毒性明显降低，并具有一定的免疫增强作用，因此，PVP-GO可以作为候选的免疫佐剂。
[Abstract]:Hepatitis B virus (Hepatitis B virus, HBV) infection can not only cause acute and chronic viral hepatitis (Acute and chronic hepatitis), but also be closely related to the occurrence and development of liver cirrhosis (Liver cirrhosis, LC) and primary hepatocellular carcinoma (Hepatocellularcarcinoma, HCC). China is a high incidence area of HBV infection. At present, there are about 93 million people infected with HBV in our country, including 20 million patients with chronic hepatitis B. Hepatitis B virus can be divided into 10 genotypes (A to J). Genotypic differences not only affect the serological transformation of e antigen, the mutation sites of pre C region promoter and pre C region, and the progression of disease, but also relate to the antiviral effect. Genotyping diagnosis helps clinicians develop individualized treatments for patients. In order to overcome the disadvantages of HBV genotyping, such as long detection time, low sensitivity and poor specificity, we used microfluidic chips, giant magnetoresistive sensors and magnetic nanoclusters. A microfluidic chip method for rapid identification of dominant genotypes B and C of Chinese HBV was developed by combining the ring mediated isothermal amplification of (Loopmediatedisothermal amplification, LAMP) with linear probe hybridization. Nucleic acid amplification and signal acquisition have many advantages, such as short detection time, high sensitivity, specificity and strong anti-interference ability. In this paper, an integrated giant magnetoresistive sensor (GMR), a microfluidic chip, is proposed. Detection of Hepatitis B virus genotyping by PCR Amplification and nucleic Acid Hybridization of Magnetic Nanoclusters. The surface of magnetic nanoclusters, about 172nm, was modified with streptavidin. The biosensor can be used to detect magnetic nanoclusters at the end of the hybrid complex "PCR product-nucleic acid probe". The detection sensitivity is up to 200IU mL-1 (103copies mL-1). Subsequently, the detection method was optimized and upgraded: we integrated the ring mediated isothermal amplification technique into microfluidic chip to amplify the nucleic acid samples efficiently. At the same time, the GMR sensor is no longer integrated in the microfluidic chip, but is used as an independent detector for reuse. Finally, genotyping of the lowest 10copies mL-1HBV DNA can be achieved within an hour. Since then, in order to achieve rapid and efficient mixing of nucleic acid samples and reaction reagents on microfluidic chips, we have based on the principle of bionics. A micromixer consisting of a straight channel unit with a high aspect ratio and a circular cell unit with a high aspect ratio is designed. In addition, in order to evaluate the possibility of graphene oxide as an immune adjuvant for HBV vaccine, we studied the effects of graphene oxide (go) and PVP modified graphene oxide (PVP-GO) on dendritic cell T lymphocytes in vitro. The effect of major immune cells such as macrophages. The results showed that the immunological toxicity of graphene oxide modified by PVP was obviously decreased and its immunological enhancement was also found. Therefore, PVP-GO could be used as a candidate immune adjuvant.
【学位授予单位】：上海交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R512.62

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