【作者】 刘艳；

【导师】 张振中；

【作者基本信息】 郑州大学 ， 药学（专业学位）， 2014， 硕士

【摘要】 光敏感型纳米给药系统凭借其高效、可控、特异性强等优点已经成为生物医学领域研究的热点。构建肿瘤靶向光敏感型纳米给药系统可以有效地调节药物的释放进而增加其对靶组织的选择性、降低化疗药物的全身毒性，从而提高抗肿瘤活性。本课题构建了一种基于氧化石墨烯/银（GO@Ag）纳米复合材料的阿霉素（DOX）近红外光（NIR）敏感型药物传递系统。首先通过化学淀积法将Ag纳米粒子（~10nm）负载在GO表面得到GO@Ag纳米复合材料，然后将DOX通过酯键连接在GO@Ag上得到GO@Ag-DOX。接着连DSPE-PEG2000-Maleimide（DPM），一方面利用DSPE-PEG2000端的强分散能力增加上述给药体系的水溶性，另一方面利用Maleimide端与NGR发生加成反应将肿瘤靶向基团NGR连接到给药系统GO@Ag-DOX的表面，从而得到肿瘤靶向NIR控释给药系统GO@Ag-DOX-NGR。使用透射电镜、X射线衍射、紫外全波长扫描、傅里叶红外光谱和粒径分析仪等对合成过程及系统形态进行表征。结果表明，成功构建了具有良好水溶性的GO@Ag-DOX-NGR载药系统。此外考察了GO@Ag-DOX-NGR载药系统在近红外光照射下DOX的释放情况以及其光热转化效应。结果表明，由于近红外光照射下Ag纳米粒的表面等离子共振效应（SPR），DOX的释放显著增加，光照24h后DOX的释放量是无光照组的3.5倍。同时，2W/cm2功率激光照射5min后，GO@Ag-DOX-NGR溶液的温度比GO溶液高约10℃。体外抗肿瘤活性实验中，以乳腺癌细胞MCF-7为实验对象，考察GO@Ag-DOX-NGR载药系统在近红外光照射下的体外抗肿瘤活性。结果表明，GO@Ag，GO@Ag-NGR无光照时在体外的毒性很小，而光照后由于GO的光热治疗作用对MCF-7细胞的毒性显著增加。载药后光照组比非光照组对MCF-7细胞的生长抑制作用大大提高，而且光照后在细胞核中观察到更多DOX的红色信号，表明NIR光照射对GO@Ag-DOX-NGR在MCF-7细胞中的释放有显著的促进作用。体内抗肿瘤活性实验中，以S180荷瘤小鼠为模型，主要考察了GO@Ag-DOX-NGR在动物体内的组织分布情况以及体内抑瘤特性，同时也研究了GO@Ag-DOX-NGR体内X-射线成像情况。结果表明DOX在肿瘤组织的分布增加，而在心脏和肾脏的分布减少；GO@Ag-DOX-NGR具有X光成像对比剂应用的潜力。综上所述，GO@Ag-DOX-NGR给药系统在体内外均具有靶向性和近红外光敏感性，并且具有X-射线成像功能。近红外敏感型药物传递系统有可能被应用于未来的肿瘤诊断和治疗中。更多还原

【Abstract】 Light-sensitive nanocarriers are attracting increasing attention in biomedicalfield due to their advantages of high efficiency, controllability and specificity.Light-sensitive drug delivery system can purposefully regulate the release of drugs toincrease their selectivity to the target tissue and reduce the toxicity of chemotherapydrugs, thus it can improve the antitumor activity of the drugs.In this study, we developed doxorubicin (DOX)-loaded near-infrared (NIR)light-responsive drug delivery system based on GO@Ag. Firstly Ag nanoparticles(~10nm) were chemically deposited onto the surface of GO to get GO@Agnanocomposites. Then DOX was covalently conjugated onto GO@Ag by an esterbond. In the connection of DSPE-PEG2000-Maleimide(DPM), DSPE-PEG2000wasconnected to GO@Ag-DOX through the dispersing effect of DSPE extremity toimprove the water-soluble; while the Maleimide was linked to NGR by additionreaction, resulting in tumor targeting NIR controlled drug delivery systemGO@Ag-DOX-NGR. The whole process was characterized by TEM,XRD, UV-Vis,FT-IR and DLS. The results showed that we built the water soluble GO@Ag-DOX-NGR drug delivery system successfully.We also studied the release of DOX from GO@Ag-DOX-NGR and its thermaleffect under the near-infrared light irradiation(NIR). Results indicated that DOXrelease can be externally triggered due to the lacalized surface plasmonresonances(SPR) of Ag nanoparticles under NIR light. The drug release profileshowed that3.5-fold higher DOX released under NIR light24h than in the dark.Besides, the temperature of GO@Ag-DOX-NGR solution was higher than GO byabout10℃after irradiated5min under2W/cm2NIR.In vitro experiments, we chose breast cancer cells MCF-7as the experimentalsubject to inspect the antitumor activity of the GO@Ag-DOX-NGR under NIR. Itturned out that the toxicity of GO and GO@Ag are very low without the irradiation ofNIR, however, the toxicity of them increased significantly due to the effect of photothermal therapy of the GO. After the linkage of DOX, the inhibition to MCF-7cells greatly enhanced and more red fluorescence (DOX signal) was observed in cellnucleus due to the presence of DOX after irradiated by NIR, indicating that NIR lightcan promote the release of GO@Ag-DOX-NGR in MCF-7cell significantly.In vivo, the S180tumor-bearing mice were chosen as the model to examine thetissue distribution and the tumor suppression of GO@Ag-DOX-NGR. Meanwhile, wealso investigated the X-ray imaging of GO@Ag-DOX-NGR in vivo. The resultsshowed that the distribution of DOX in tumor increased while decreased in heart andkidney under NIR. The drug system GO@Ag-DOX-NGR also had the characteristicsof X-ray imaging.To sum up, the drug delivery system GO@Ag-DOX-NGR is targeting and NIRsensitive. Besides, it has the function of X-ray imaging. The NIR-responsive drugdelivery may be promising for the in future cancer therapy.更多还原