乳糖酸修饰的低代数PAMAM包裹金纳米颗粒的制备、功能化及其肿瘤CT成像应用
发布时间：2018-08-29 15:26
【摘要】：计算机断层扫描（CT）是应用最为广泛的分子影像技术之一，传统的临床用CT造影剂为含碘的小分子（例如碘海醇），但是含碘小分子存在一些应用缺陷和限制。随着科学技术尤其是纳米科学和纳米技术的发展，各种各样的纳米粒子被开发用于CT造影剂，它们具备优秀的X-射线衰减系数、生物相容性、低毒性，有些更具备靶向性能。其中的代表之一是用聚酰胺-胺树状大分子为载体的金纳米颗粒。在前期的工作中，我们利用第五代聚酰胺-胺树状大分子（G5.NH2）大量的表面官能团进行功能化修饰（聚乙二醇（polyethylene glycol，PEG）），靶向分子或者药物），而后控制该功能化载体与金的比例制备树状大分子包裹或树状大分子稳定的金纳米颗粒CT造影剂，获得更长的造影时间、更好的造影效果、肿瘤靶向造影能力甚至实现诊疗一体化。 由于G5.NH2制备成本高价格较贵，不利于产业化，我们也尝试用相对便宜易得的第二代聚酰胺-胺树状大分子（G2.NH2）作为载体开发CT造影剂，分别用水热法和硼氢化钠（NaBH4）快速还原法制备G2.NH2包裹的金纳米颗粒和G2.NH2稳定的金纳米颗粒，取得良好的造影效果。其中PEG的修饰大大提高了对金的包裹量，叶酸（FA）靶向分子的修饰实现了肿瘤特异性CT造影。 本论文中，我们选择G2.NH2作为模板包裹金纳米颗粒。采用NaBH4快速还原法包裹金之前，G2.NH2表面先后共价连接异硫氰酸荧光素（FITC）和修饰有乳糖酸（LA）的PEG-LA。乳糖酸含的半乳糖基团对去唾液酸糖蛋白受体（asialoglycoprotein receptors，ASGPR）过表达的HepG2细胞（人源肝癌细胞株）有特异性结合作用。对最终形成的具靶向性的树状大分子包裹的金纳米颗粒（以下简称LA-Au DENPs）的物化性质和使用性能进行一系列测试表征。 结果显示，，该金纳米颗粒平均粒径为1.8nm，在4-50℃和pH=5-8的范围内的水溶液中均稳定；当材料浓度高达3000nM时，仍然显示良好的细胞相容性；流式细胞术结果证实了体外环境下LA-Au DENPs对HepG2细胞有特异性结合作用；细胞的CT扫描结果同样反映了体外环境下该材料对HepG2细胞的特异性结合作用；肝癌裸鼠模型的CT扫描结果显示肿瘤部位有增强造影效果；一个月后的裸鼠各脏器的HE染色结果与正常小鼠基本无异，证明该材料没有明显毒性或副作用。 综上，该异硫氰酸荧光素标记、乳糖酸修饰的聚乙二醇化低代数树状大分子包裹的金纳米颗粒具备良好的稳定性、生物相容性，对原发性肝癌（hepatocellularcarcinoma，HCC）的早期诊断有一定的潜在应用价值。
[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
本文编号：2211621
[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
本文编号：2211621
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