磁性四氧化三铁纳米粒在磁共振/光热双模式成像中的应用

Application of magnetic iron oxide nanoparticles in magnetic resonance/photothermal dual-modal imaging

本文利用水热法制备了水分散性的磁性四氧化三铁(magnetic iron oxide,Fe_3O_4)纳米粒,采用透射电镜(transmission electron microscopy,TEM)、振动样品磁强计(vibrating sample magnetometer,VSM)等手段对其进行表征,进而对其体外磁共振响应及光热转换特性进行了考察。此外,研究了Fe_3O_4纳米粒的细胞摄取、细胞毒性及体内分布情况,并分析了其在肿瘤部位磁共振/光热双模式成像中的应用效果。结果表明,所制备的磁性纳米粒为大小均一的球型,粒径约为125 nm。该纳米粒表现出超顺磁性及良好的磁共振响应和光热转换性能。细胞实验结果显示,该磁性纳米粒能够被肿瘤细胞摄取,同时具有较好的生物相容性。小鼠尾静脉注射后,该纳米粒能够靶向聚集于肿瘤部位,并实现该部位磁共振/光热双模式成像。以上结果表明,Fe_3O_4纳米粒具有潜在的多模式生物成像应用前景,可能在肿瘤的诊断中发挥重要作用。

In this study, water-dispersible magnetic iron oxide（Fe_3O_4） nanoparticles were synthesized with solvothermal method. The nanoparticles were characterized with a transmission electron microscopy（TEM） and vibrating sample magnetometer（VSM）. The in vitro magnetic resonance response and photothermal conversion characteristics of the nanoparticles were evaluated. In addition, the cellular uptake, cytotoxicity and biodistribution were studied. Finally, magnetic resonance/photothermal dual-modal imaging effect of the as-synthesized Fe_3O_4 nanoparticles was investigated in the tumor-bearing mice. The results showed that the obtained magnetic nanoparticles were uniform with a mean diameter of about 125 nm. Moreover, the superparamagnetic Fe_3O_4 nanoparticles showed remarkable magnetic resonance response and photothermal conversion properties. The results of cellular experiments showed that the cell viability was nearly 85% even the concentration of the nanoparticles was up to 1 000 μg·m L-（-1）, an indicator of good biocompatibility. In addition, the nanoparticles could be taken up by the tumor cells and then located in the cytoplasm. After intravenous injection, the nanoparticles were tended to enrich in the tumor over time, which is helpful in achieving dual-modal magnetic resonance/photothermal imaging. In sum, the obtained Fe_3O_4 nanoparticles showed great potential to be applied for multi-modal bio-imaging which may play an important role in the diagnosis of tumors.