聚乙二醇连接荧光Cy5.5构建超小超顺磁性氧化铁成像探针的制备与表征

摘要 目的：以超小超顺磁性氧化铁颗粒为载体通过聚乙二醇连接荧光Cy5.5构建核磁/荧光分子探针并表征。方法：取Cy5.5-NHS荧光粉末溶于二甲基甲砜（Dimethyl sulfoxide，DMSO）溶液，将PEG四氧化三铁颗粒离心超滤之后用磷酸盐缓冲液（Phosphate Buffered Saline，PBS）重悬纳米颗粒改变PEG化四氧化三铁纳米颗粒溶液pH。将配置好的Cy5.5荧光加入到四氧化三铁颗粒中，恒温摇床孵育，通过离心过滤器去除较大铁离子与未结合的荧光，静置后检测水合粒径及Zeta电位，纽麦小核磁检测其驰豫率，CCK-8实验检测其细胞毒性，激光共聚焦显微镜观察探针被细胞摄取情况。结果：合成Cy5.5-PEG-FeO₄探针，透射电镜（Transmission electron microscope，TEM）显示探针粒径为16.8±2.4nm，纳米颗粒的水合径为43.4±17.6 nm，Zeta电位为-18.0 mV。驰豫率为39.5 mM^-1?s^-1，R²为0.98。细胞毒性实验结果显示对细胞有轻微毒性，且毒性与浓度呈依赖性。激光共聚焦结果显示此款探针可顺利被细胞摄取。结论：成功合成Cy5.5-PEG-FeO₄探针。

Preparation and Characterization of Ultra Small Superparamagnetic Iron Oxide Imaging Probe Constructed by Fluorescent Cy5.5 Linked with Polyethylene Glycol

ABSTRACT Objective: The ultra-small superparamagnetic iron oxide particles were used as the carrier to construct and characterize nuclear magnetic/fluorescent molecular probes through polyethylene glycol-linked fluorescent Cy5.5. Methods: Ake a small amount of Cy5.5-nhs fluorescent powder and dissolve it in dimethyl sulfoxide (DMSO) solution. After centrifugation and ultrafiltration of PEG ferric oxide particles, resuspend the nanoparticles with phosphate buffered saline (PBS) to change the pH of PEG ferric oxide nanoparticle solution. The configured cy5.5 fluorescence was added to Fe3O4 particles, incubated in a constant temperature shaking table, and the larger iron ions and unbound fluorescence were removed through a centrifugal filter. After standing, the hydrated particle size and zeta potential were detected, the relaxation rate was detected by newwheat nuclear magnetic resonance, the cytotoxicity was detected by CCK-8 experiment, and the uptake of the probe by cells was observed by laser confocal microscope. Results: The Cy5.5-PEG-Fe₃O₄ probe was successfully synthesized. Transmission electron microscope (TEM) showed that the diameter of the probe was 16.8±2.4nm, the water and diameter of the nanoparticles were 43.4±17.6 nm, and the Zeta potential was -18.0 mV. The relaxation rate is 39.5 mM^-1?s^-1 and the slope is 0.98. The results of cytotoxicity experiments show that it is slightly toxic to cells, and the toxicity is dependent on the concentration. Laser confocal results show that this probe can be taken up by cells smoothly. Conclusion: This experiment successfully synthesized Cy5.5-PEG-Fe₃O₄ probe.