论文部分内容阅读
目的合成具备MR显像和基因传输功能的纳米载体,探讨载体对间充质干细胞(MSCs)的基因传输功能及其联合生物发光成像(BLI)和MRI对MSCs双模态示踪的能力。方法合成三元共聚物聚乙二醇-聚天冬氨酸(聚乙烯亚胺)-超顺磁性氧化铁纳米颗粒载体(PAI/SPION);利用凝胶阻滞实验分析载体携带质粒(pDNA)的能力;电位及粒度测定仪测量载体复合pDNA后的粒径和电位;采用大鼠股骨骨髓分离培养MSCs;采用流式细胞仪、激光共聚焦显微镜评估PAI/SPION/pDNA对MSCs的基因转染效率;联合BLI和MRI双模态示踪MSCs。结果成功合成了载体PAI/SPION。氨基与质粒磷酸根的摩尔比(N/P)=3.0时,PAI/SPION可完全复合pDNA。N/P=12时,粒径趋于稳定,为(74.8±8.1)nm,电位为(12.2±1.5)mV,载体对MSCs的基因转染率为(71.2±2.3)%。激光共聚焦显微镜下,胞浆内可见大量表征PAI/SPION的绿色荧光和表征pDNA的红色荧光,且MSCs生物发光强度最高,T2*WI标准化信号强度最低。结论本研究成功合成了MRI可视的基因传输载体PAI/SPION;载体可高效传输pDNA至大鼠MSCs,且可成功联合BLI和MRI双模态示踪MSCs。
OBJECTIVE: To synthesize nanocarriers with MR imaging and gene transfer functions and to explore the gene transfer function of vector for mesenchymal stem cells (MSCs) and its dual biomimetic tracing with bioluminescence imaging (BLI) and MRI. Methods Polyethylene glycol-polyaspartic acid (polyethylenimine) - superparamagnetic iron oxide nanoparticle carrier (PAI / SPION) was synthesized by the method of gel permeation chromatography. The carrier-carrying plasmid (pDNA) . The size and potential of the pDNA after the carrier complex was measured by potentiometric and particle size analyzer. The MSCs were isolated and cultured using rat femur bone marrow. The transfection of MSCs by PAI / SPION / pDNA was evaluated by flow cytometry and confocal laser scanning microscopy Efficiency; combined with BLI and MRI dual modality tracer MSCs. Results The vector PAI / SPION was successfully synthesized. PAI / SPION can completely complex pDNA when the molar ratio of amino group to plasmid phosphate (N / P) = 3.0. At N / P = 12, the particle size tended to be stable (74.8 ± 8.1) nm and the potential was (12.2 ± 1.5) mV. The gene transfection efficiency of MSCs was (71.2 ± 2.3)%. Under confocal laser scanning microscopy, a large number of green fluorescence characterizing PAI / SPION and red fluorescence characterizing pDNA were observed in the cytoplasm. The strongest bioluminescence intensity of MSCs and the lowest T2 * WI signal intensity were observed. CONCLUSION: MRI-based gene delivery vector PAI / SPION was successfully synthesized in this study. The vector can efficiently transfer pDNA to rat MSCs, and successfully combined with BLI and MRI dual-mode tracing of MSCs.