探讨叶酸（FA）介导的超顺磁性氧化铁纳米颗粒（PEG-PCL-SPIO）对于人舌癌细胞Tca-8113的靶向性及磁共振成像（MRI）的可行性。

制备PEG-PCL-SPIO探针及FA靶向修饰的探针PEG-PCL-FA-SPIO，通过MTT试验验证其细胞毒性，并分别用PEG-PCL-SPIO（非靶向组）、PEG-PCL-FA-SPIO（靶向组）与人舌癌细胞Tca-8113（1 × 10⁶）共同培育0.5、1、2 h后做细胞悬液的MRI检查，测量横向弛豫时间（T₂值）变化。采用普鲁士蓝染色观察SPIO进入细胞内的情况。

MTT比色试验培养液中不同浓度的PEG-PCL-FA-SPIO的细胞活性，各组间的差异无统计学意义（F = 0.698，P = 0.676）。两种探针分别与Tca-8113细胞培育后0.5、1、2 h后MRI检查，两组细胞悬液的T₂加权成像信号均下降，以2 h后更明显，靶向组在各时间段T₂值下降的百分比均高于非靶向组（F = 518.064，P = 0.000）。普鲁士蓝染色显示，两种标记的细胞内均可见蓝色颗粒，靶向组中的蓝色颗粒比非靶向组的蓝色颗粒更多。

PEG-PCL-FA-SPIO对Tca-8113细胞有良好的靶向性，对舌癌的早期诊断具有重大应用潜力。

To explore the feasibility of the human tongue cancer cell (Tca-8113) targeting and magnetic resonance imaging (MRI) abilities of the folate mediated superparamagnetic iron oxide nanoparticles (PEG-PCL-FA-SPIO) .

Both PEG-PCL-SPIO probes and PEG-PCL-FA-SPIO probes with folate targeted modification were prepared. The cytotoxicity of PEG-PCL-FA-SPIO was verified through MTT assay. Tca-8113 cell (1 × 10⁶) were cultured with PEG-PCL-SPIO (non-targeting) and PEG-PCL-FA-SPIO (folate targeting) , respectively. Each group underwent MRI scan after cultured for 0.5, 1, 2 h, and the relative T₂ values were recorded. Endocytosis of SPIO was observed through prussian blue staining.

The cell viability of PEG-PCL-FA-SPIO in different concentrations showed no statistical difference according to the MTT assay (F = 0.698, P = 0.676) . Both the two probes were cultured with Tca-8113 cells for 0.5, 1, 2 h, respectively and the MRI demonstrated decreased T₂WI signal intensity of both groups, especially at 2 h. The folate targeting group showed a more significant decrease of relative T₂ value at each time point (F = 518.064, P = 0.000) . Intracellular blue particles were observed in both groups after prussian blue staining, and the particles in folate targeting group were more than that of the non-targeting group.

PEG-PCL-FA-SPIO has favourable Tca-8113 cell targeting ability, and shows great potential in the early diagnosis of tongue cancer.