【作者】 周莹；

【导师】 姜立萍；

【作者基本信息】 南京大学 ， 化学， 2016， 硕士

【摘要】 摇铃型中空介孔二氧化硅是核-壳结构的特殊类别,一般包括核、空腔、壳三个部分,不仅兼有硅纳米材料无毒、稳定、生物相容性好、表面易功能化等优点,由于独特的结构,还可以作为普适的药物载体、灵敏的纳米传感器以及稳定的催化反应器。目前,很多研究者将具有光、电、磁性能的无机纳米材料作为核,使得该材料具有光学成像、磁性导向、金属催化等功能,再利用其中空介孔结构的大负载量、智能的释放方式等,发展了一系列多功能化的药物载体以及传感器。本论文利用摇铃型中空介孔二氧化硅独特的核-壳结构、出色的载药能力以及成熟的表面修饰技术开发了可用于细胞内生物小分子检测与成像的比率荧光传感器和能克服乳腺癌耐药性的靶向药物递送系统。论文的主要内容如下:1.基于FITC掺杂的摇铃型二氧化硅纳米颗粒设计的比率荧光传感器用于超氧阴离子的生物传感与成像表面修饰过程的复杂性以及环境因素的干扰,限制了荧光纳米传感器在实际生物样品中的应用,因次,本文致力于开发一种简便、普适的方法来实现对生物小分子的比率荧光检测。以超氧阴离子的检测为例,传感器主要由三个部分构成:探针载体,摇铃型二氧化硅纳米颗粒(mSiO2@hmSiO2 NPs);掺杂在二氧化硅核中的参比荧光团,异硫氰酸荧光素(FITC);负载在空腔中的检测O2-的荧光探针,二氢乙锭(HE)。无O2·-时,传感器只发射FITC在518 nm的绿色荧光;当释放的二氢乙锭被O2·-氧化后,会发射位于570 nm处的红色荧光,而FITC的荧光强度不变。结果显示传感器对O2·-的线性检测范围为0.2-20 μM,最低检测限为80 nM。该传感器还成功地实现了活细胞中O2·-的双通道成像,以及通过荧光颜色的改变直观地区分了处于正常状态或氧化应激条件下的细胞。因此,只要选择合适的参比染料以及荧光探针,就能够实现对生物小分子的比率传感与成像,该设计能够为荧光传感器的生物应用提供一种简便、准确、通用性的思路。2.级联靶向纳米颗粒在透明质酸酶诱导下同时释放抗癌药物以及siRNA用于耐药型乳腺癌的治疗乳腺癌在转移后会过表达结缔组织生长因子(CTGF),产生耐药性而影响治疗效果。本设计在摇铃型中空介孔二氧化硅(rmSiO2)载体上修饰级联靶向材料PEGA-pVEC肽和透明质酸(HA),同时将抗癌药物(阿霉素,Dox)和siRNA负载在rmSiO2的不同位置,用于治疗CTGF过表达的耐药型乳腺癌。首先,级联靶向的纳米颗粒在PEGA-pVEC肽的介导下,选择性聚集在血管中,而后通过HA介导的内吞进入CD44受体过表达的乳腺癌细胞,对活体实验而言,级联靶向纳米材料的靶向能力优于单靶向的颗粒。另一方面,HA能够防止药物在运输过程中的提前泄露,纳米粒子被细胞内吞进入溶酶体后,由透明质酸酶引发HA层降解,确保药物在细胞内特定位置的可控释放。当HA层破裂后,siRNA进入细胞质中沉默与耐药性有关的基因CTGF,有利于增强阿霉素诱导的细胞凋亡。总之,级联靶向为癌症的精准治疗提供了一条新的设计思路,而siRNA的引入可增强对耐药型癌症的治疗效果。更多还原

【Abstract】 Rattle-type hollow mesoporous silica is a special type of core-shell structure and usually made up of three different components,namely core,void and shell.Just like many other silica nanomaterials,the hollow silica shows non-toxicity,high stability,good biocompatibility,easy surface modification.Besides,due to its special structure,it can also serve as universal drug carrier,sensitive nanosensor and stable catalytic nanoreactor.Now,nanomaterials with novel optical,electric,magnetic properties have been used as cores for optical imaging,magnetic guiding,metal catalysis.Furthermore,in combination with its good loading capability and smart drug releasing profile,many multi-functionalized nanocarriers and nanosensors have been developed.In this article,by taking advantages of the special core-shell structure,excellent drug loading capability and mature surface modification technique,we develop an excellent ratiometric fluorescent nanosensor for biosensing and imaging of bioactive small molecules,and a targeting delivery system for drug-resistant breast cancer therapy.The main contents are as follows:1.FITC Doped Rattle-type Silica Colloidal Particle-Based Ratiometric Fluorescent Sensor for Biosensing and Imaging of Superoxide AnionDue to the complicated surface modification process and background interference,applications of fluorescent nanosensor in practical biological samples are limited.Here,a simple,universal method was developed for ratiometric fluorescent determination of general small molecules.Taking superoxide anion(O2·-)as an example,the designed sensor was composed of three main moieties:probe carrier,rattle-type silica colloidal particles(mSiO2@hmSiO2 NPs);reference fluorophore doped into the core of NPs,fluorescein isothiocyanate(FITC);fluorescent probe for superoxide anion,hydroethidine(HE).In the absence of the sensor just emitted green fluorescence of FITC at 518 nm.When released HE was oxidized by O2·-,the oxidation product exhibited red fluorescence at 570 nm and the intensity was linearly associated with the concentration of O2·-,while that of reference element remained constant.Accordingly,ratiometric determination of O2·-was sensitively and selectively achieved with a linear range of 0.2-20 μM and the detection limit was calculated as low as 80 nM.Besides,the technique was also successfully applied for dual-emission imaging of O2·-in live cells and realized visual recognition with obvious fluorescence color change in normal condition or under oxidative stress.As long as appropriate reference dyes and sensing probes are selected,ratiometric biosensing and imaging of bioactive small molecules would be achieved.Therefore,the design could provide a simple,accurate,universal strategy for biological applications.2.Hyaluronidase-triggered Anticancer Drug and siRNA Delivery from Cascaded Targeting Nanoparticles for Drug-resistant Breast CancerMetastatic breast cancers over express connective tissue growth factor(CTGF),resulting in drug resistance and ineffective standard chemotherapy.Rattle-type hollow mesoporous silica(rmSiO2)was used for therapy of CTGF over-expressing breast cancer by co-embedding breast tumor homing cell-penetrating peptide(PEGA-pVEC)and hyaluronic acid(HA)as cascaded targeting media,as well as loading siRNA and anticancer drug in different locations simultaneously to overcome drug resistance.The cascaded targeting nanoparticles first selectively accumulated in the vasculatures under the guidance of PEGA-pVEC,cascaded by another targeting agent HA-mediated endocytosis,presenting greater in vivo tumor targeting ability than single targeting ligand vectors.In another sense,HA shell prevented the leakage of therapeutic drug during the cargo transport process,until the hyaluronidase(HAase)-triggered degradation upon entering lysosomes,guaranteeing controllable drug release inside the target cells.As protective shell disintegrated,siRNA was released into the cytoplasm to silence the gene associated with drug resistance,CTGF,thus facilitating the Dox-induced apoptosis.The cascaded targeting media(PEGA-pVEC,HA)advances the precision-guided therapy in vivo,while the encapsulation of siRNA into chemotherapy drug delivery system provides an efficient strategy for the treatment of drug-resistant cancers.更多还原