目的: 研究叶酸偶联的超顺磁Fe3O4纳米颗粒对活体肝癌标记效果和MRI成像功能。方法: 以铁盐、十二烷基苯磺酸和3-氨基丙基3-乙氧基硅烷为原料, 通过共沉淀法合成了APTES修饰的超顺磁Fe3O4纳米颗粒, 通过酰胺化法合成了叶酸偶联的超顺磁Fe3O4纳米颗粒, 以X射线衍射仪、透射电镜、红外光谱仪、振动样品磁强计、动态光散射仪对合成材料进行表征, 采用SRB法对叶酸偶联的超顺磁Fe3O4纳米颗粒细胞进行安全性检测, 同时建立活体瘤鼠动物模型, 对其在叶酸偶联的超顺磁Fe3O4纳米颗粒标记前后进行MRI成像对比检测, 每个肿瘤组织块各取2套切片, 分别行苏木素-伊红染色和普鲁士蓝染色, 观察肿瘤组织光镜下形态及组织内含Fe情况。结果: 所制备的叶酸偶联的Fe3O4纳米颗粒为立方相的Fe3O4, 粒径约8 nm左右, 水合直径25.7 nm, 呈近似球形, 表面分布有羧基等功能基团, 呈超顺磁特性, 饱和磁化强度为51 emu/g Fe。叶酸偶联的超顺磁Fe3O4纳米颗粒对人皮肤成纤维细胞(HSF)的生长与生理盐水对照组的影响一样, 无明显抑制细胞生长的表现。同时, 磁共振成像和染色结果均显示肿瘤的存在。结论: 叶酸偶联的超顺磁Fe3O4纳米颗粒, 不仅细胞毒性小, 而且因其表面的叶酸与叶酸受体之间的高强结合力。同时, 它能通过这种结合作用被高效介导进入肿瘤细胞内, 增强MRI成像中肿瘤组织与周围正常组织的对比度, 有利于肿瘤细胞的标记、示踪和靶向检测, 是一种很有应用前景的肿瘤细胞靶向检测物质。

Objective: To research the labeling effect of folate-conjugated Fe3O4 nanoparticles on hepatocellular carcinoma in vivo and the function of MRI imaging. Methods:ATPES-modified Fe3O4 nanoparticles were synthesized through co-precipitation action using iron salt, sodium dodecyl benzene sulfonate and 3-Aminopropyltriethoxysilane as raw materials. Folate-conjugated superparamagnetic Fe3O4 nanoparticles were synthesized through amide action. The synthesized folate-conjugated Fe3O4 nanoparticles were characterized by X-ray diffraction diffractometer, transmission electron microscope, FT-IR spectrometer, vibrating sample magnetometer, and dynamic light scattering instrument. Using SRB method to conduct the safety detection of folate-conjugated superparamagnetic Fe3O4 nanoparticles. Meanwhile, living tumor rat models marked before and after by folate-conjugated superparamagnetic Fe3O4 nanoparticles were established to conduct a MRI imaging comparison test. Two sets of slices for hematoxylin-eosin staining and Prussian blue staining were collected from each tumor sample. The tumor morphology and Fe content were determined under a light microscope. Results: The prepared folate-conjugated superparamagnetic Fe3O4 nanoparticles are cubic-phase Fe3O4 with a particle size of about 8 nm and hydrated diameter of 25.7 nm, and the shape is close to spherical. They cannot significantly inhibit human skin fibroblast cell growth compared with normal saline.Meanwile, the results of magnetic resonance imaging and dyeing indicate the presence of tumor. Conclusion:Folate-conjugated superparamagnetic Fe3O4 nanoparticles are not only with low toxicity but also with high binding power between folic acid receptor and folate on the surface of it. Meanwile, the folate-conjugated superparamagnetic Fe3O4 nanoparticles could be effectively mediated into the tumor cells through the binding of folate and folic acid receptor, enhancing the signal contrast of tumor tissue and surrounding normal tissue in MRI imaging. It is convenient to use folate-conjugated superparamagnetic Fe3O4 nanoparticles for tumor cells labeling, tracing, MRI target detection.It is a very promising targeted testing material for tumor cell.