To develop dual-modal fluorescence-MRI bioimaging probe which intergrates the advantages of both techniques, using water-soluble superparamagnetic nanocrystals of cobalt-doped iron oxide Co0.9Fe2.1O4 as precursor, a novel multifunctional nano-probe PTTA-Eu3+-CoFeO-FA with long-lived luminescence, superparamagnetism and cancer cell targetable property has been prepared by conjugating a luminescent europium(III) complex PTTA-Eu3+ [(4′-phenyl-2,2′:6′,2″-terpyridine-6,6″-diyl) bis(methylenenitrilo) tetrakis(acetate)-Eu3+] and a biomarker of tumor cells, folic acid (FA) onto the surface of the nanocrystals.The nano-probe not only can emit distinctly long-lived red luminescence of the Eu3+ complex, but also possesses well T2-weighted MRI (magnetic resonance imaging) property (the transverse relaxivity (r2) of proton in the aqueous solution of nanoparticles is 183.7 L/(mmol·s).These unique properties enable the nano-probe to be used for both time-resolved luminescence imaging of living cancer cells and MRI of living animals.The feasibility of the probe has been demonstrated by time-resolved luminescence imaging of Raw 264.7 cells and T2-weighted MR imaging of KM mouse.%为了开发具有荧光-磁共振双模式成像功能的生物成像探针,有效结合磁共振和荧光2种成像技术的优点,本论文以具有良好单分散性和水溶性的超顺磁性钴掺杂的氧化铁纳米粒子Co0.9Fe2.1O4为前驱体,将铕(III)与4′-苯基-2,2′:6′,2″-联三吡啶-6,6″-二甲胺四乙酸的荧光配合物(PTTA-Eu3+)及癌细胞靶向识别分子叶酸(FA)与纳米粒子共价偶联,制备出了1种具有长寿命荧光、超顺磁性(横向弛豫时间T2加权磁共振成像功能)及癌细胞靶向识别性能的多功能纳米生物探针PTTA-Eu3+-CoFeO-FA.这种纳米生物探针不仅可发出铕(III)配合物特有的长寿命红色荧光信号,还具有良好的T2加权磁共振成像(MRI)造影剂功能(纳米粒子水溶液的质子横向弛豫速率r2达183.7 L/(mmol·s),使其既可用于癌细胞的时间分辨荧光成像测定,也可用于活体动物的磁共振成像检测.利用所制备的新探针成功地实现了小鼠单核巨噬细胞白血病细胞Raw 264.7的时间分辨荧光成像和昆明鼠的活体T2加权磁共振成像检测.
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