目的:构建近红外荧光探针修饰的铁蛋白纳米颗粒,研究其作为体内成像系统的安全性以及在小鼠体内的生物分布情况和对肿瘤组织的靶向性.方法:通过在铁蛋白(ferritin)表面人工设计半胱氨酸点突变,通过半胱氨酸巯基和含有马来酰亚胺(maleimide)的Dy731近红外荧光探针分子进行巯基偶联,对铁蛋白纳米颗粒表面进行功能化修饰,使荧光探针以共价的形式结合在蛋白纳米颗粒的表面;将近红外荧光探针修饰过的铁蛋白纳米颗粒(Dy731-Ft)与5％w/v琼脂糖溶液混合冷却后制成凝胶,置于小鼠皮下和腹腔肌肉壁下,检测蛋白纳米颗粒穿透皮肤和肌肉组织的能力;将Dy731-Ft蛋白纳米颗粒通过尾静脉对小鼠进行活体注射,观察小鼠是否产生急性不良反应,检测近红外荧光强度以观察Dy731-Ft作为体内成像系统在小鼠体内的分布情况;构建U87-MG肿瘤异种移植动物模型,进行尾静脉注射验证Dy731-Ft在荷瘤小鼠组织器官内的分布和对于肿瘤组织的靶向性.结果:通过动物实验表明,小鼠体内注射铁蛋白纳米颗粒和显像期间及之后均未见急性不良反应,说明铁蛋白纳米颗粒具有良好的生物相容性,进入体内主要在肝脏积累.结论:近红外Dy731-Ft蛋白纳米颗粒能够靶向U87-MG肿瘤组织,推测其在肿瘤组织内的积累可能与转铁蛋白受体1(transferrin receptor 1,TfR-1)介导的细胞内吞作用和肿瘤组织增强渗透性以及滞留效应(enhanced permeability and retention effect,EPR)的协同作用相关.
In Vivo Imaging and Tumor Targeting of Ferritin Protein Nanoparticles
Objective:To construct ferritin nanoparticles modified with near-infrared fluorescent probes,and to study their bio-safety as an in vivo imaging system,biological distribution in mice,and tumor targeting.Methods:By artificially designing cysteine point mutation on the surface of ferritin,the surface of ferritin nanoparticles was functionalized with Dy731 fluorescent probe by sulfhydryl coupling of cysteine sulfhydryl groups and the maleimide group of the Dy731 dye.Ferritin nanoparticles(Dy731-Ft)modified with near-infrared fluorescent probes were mixed with 5％w/v agarose solution and cooled to form a gel.The gel was placed under the skin and abdominal muscle wall of mice to determine the ability of Dy731-Ft to penetrate skin and muscle tissue.Dy731-Ft protein nanoparticles were injected into mice through the tail vein to observe whether acute adverse reactions occurred in mice and to detect the in vivo near-infrared fluorescence intensity and observe the bio-distribution of Dy731-Ft as an in vivo imaging system in mice.U87-MG tumor xenograft models were constructed and the distribution of Dy731-Ft within the tissues and organs of tumor-bearing mice and its targeting to tumor tissues were verified by tail vein injection.Results:The results showed that no acute adverse reactions were observed during and after the injection of ferritin nanoparticles into mice,indicating that ferritin nanoparticles have good biocompatibility.Dy731-Ft accumulates mainly in the liver after in vivo injection.Conclusion:Near-infrared Dy731-Ft protein nanoparticles can target U87-MG tumor tissues,and its accumulation in tumor tissues may be related to the synergistic effect of the transferrin receptor 1(TfR-1)mediated cellular endocytosis and enhanced permeability and retention effect(EPR)in tumor tissues.
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