【摘要】：計算機(jī)斷層掃描（CT）是應(yīng)用最為廣泛的分子影像技術(shù)之一，傳統(tǒng)的臨床用CT造影劑為含碘的小分子（例如碘海醇），但是含碘小分子存在一些應(yīng)用缺陷和限制。隨著科學(xué)技術(shù)尤其是納米科學(xué)和納米技術(shù)的發(fā)展，各種各樣的納米粒子被開發(fā)用于CT造影劑，它們具備優(yōu)秀的X-射線衰減系數(shù)、生物相容性、低毒性，有些更具備靶向性能。其中的代表之一是用聚酰胺-胺樹狀大分子為載體的金納米顆粒。在前期的工作中，我們利用第五代聚酰胺-胺樹狀大分子（G5.NH2）大量的表面官能團(tuán)進(jìn)行功能化修飾（聚乙二醇（polyethylene glycol，PEG）），靶向分子或者藥物），而后控制該功能化載體與金的比例制備樹狀大分子包裹或樹狀大分子穩(wěn)定的金納米顆粒CT造影劑，獲得更長的造影時間、更好的造影效果、腫瘤靶向造影能力甚至實現(xiàn)診療一體化。 由于G5.NH2制備成本高價格較貴，不利于產(chǎn)業(yè)化，我們也嘗試用相對便宜易得的第二代聚酰胺-胺樹狀大分子（G2.NH2）作為載體開發(fā)CT造影劑，分別用水熱法和硼氫化鈉（NaBH4）快速還原法制備G2.NH2包裹的金納米顆粒和G2.NH2穩(wěn)定的金納米顆粒，取得良好的造影效果。其中PEG的修飾大大提高了對金的包裹量，葉酸（FA）靶向分子的修飾實現(xiàn)了腫瘤特異性CT造影。 本論文中，我們選擇G2.NH2作為模板包裹金納米顆粒。采用NaBH4快速還原法包裹金之前，G2.NH2表面先后共價連接異硫氰酸熒光素（FITC）和修飾有乳糖酸（LA）的PEG-LA。乳糖酸含的半乳糖基團(tuán)對去唾液酸糖蛋白受體（asialoglycoprotein receptors，ASGPR）過表達(dá)的HepG2細(xì)胞（人源肝癌細(xì)胞株）有特異性結(jié)合作用。對最終形成的具靶向性的樹狀大分子包裹的金納米顆粒（以下簡稱LA-Au DENPs）的物化性質(zhì)和使用性能進(jìn)行一系列測試表征。 結(jié)果顯示，，該金納米顆粒平均粒徑為1.8nm，在4-50℃和pH=5-8的范圍內(nèi)的水溶液中均穩(wěn)定；當(dāng)材料濃度高達(dá)3000nM時，仍然顯示良好的細(xì)胞相容性；流式細(xì)胞術(shù)結(jié)果證實了體外環(huán)境下LA-Au DENPs對HepG2細(xì)胞有特異性結(jié)合作用；細(xì)胞的CT掃描結(jié)果同樣反映了體外環(huán)境下該材料對HepG2細(xì)胞的特異性結(jié)合作用；肝癌裸鼠模型的CT掃描結(jié)果顯示腫瘤部位有增強(qiáng)造影效果；一個月后的裸鼠各臟器的HE染色結(jié)果與正常小鼠基本無異，證明該材料沒有明顯毒性或副作用。 綜上，該異硫氰酸熒光素標(biāo)記、乳糖酸修飾的聚乙二醇化低代數(shù)樹狀大分子包裹的金納米顆粒具備良好的穩(wěn)定性、生物相容性，對原發(fā)性肝癌（hepatocellularcarcinoma，HCC）的早期診斷有一定的潛在應(yīng)用價值。
[Abstract]:Computed tomography (CT) is one of the most widely used molecular imaging techniques. The traditional CT contrast agent is a small molecule containing iodine (such as iodiol), but there are some defects and limitations in its application. With the development of science and technology, especially nanoscience and nanotechnology, a variety of nanoparticles have been developed for CT contrast agents, they have excellent X- ray attenuation coefficient, biocompatibility, low toxicity, some have more targeted performance. One of them is gold nanoparticles supported by polyamide-amine dendrimers. In previous work, We use the fifth generation polyamide-amine dendrimer (G5.NH2) to functionalize the poly (ethylene glycol (polyethylene glycol,PEG),) target molecule or drug), and then control the ratio of the functional carrier to gold to prepare a large dendritic fraction. Encapsulated or dendritic macromolecular stabilized gold nanoparticles CT contrast agent, To obtain longer time, better imaging effect, tumor targeting ability and even achieve the integration of diagnosis and treatment. Because of the high cost of G5.NH2 preparation is not conducive to industrialization, we also try to use relatively cheap polyamide-amine dendrimer (G2.NH2) as a carrier to develop CT contrast agent. G2.NH2 coated gold nanoparticles and G2.NH2 stable gold nanoparticles were prepared by hydrothermal method and sodium borohydride (NaBH4) rapid reduction method respectively. The modification of PEG greatly increased the encapsulation of gold, and the modification of folic acid (FA) target molecule achieved tumor-specific CT. In this thesis, we chose G2.NH2 as template to encapsulate gold nanoparticles. Covalent bonding of fluorescein isothiocyanate (FITC) and PEG-LA. modified with lactate (LA) on the surface of G2.NH2 by NaBH4 rapid reduction method Galactose groups containing lactate have specific binding effect on HepG2 cells (human hepatoma cell line) overexpressed sialate glycoprotein receptor (asialoglycoprotein receptors,ASGPR). The physicochemical properties and application properties of the resulting dendritic macromolecular encapsulated gold nanoparticles (LA-Au DENPs) were characterized by a series of tests. The results showed that the average diameter of the gold nanoparticles was 1.8 nm, which was stable in aqueous solution at 4-50 鈩

本文編號：2211621