肿瘤主动靶向磁性纳米粒子研究现状及其在肿瘤热疗中的应用

 磁性纳米粒子已广泛应用于肿瘤的成像和治疗，但限制其临床应用的重大障碍是纳米粒子在肿瘤部位不能达到足够的浓度。主动靶向磁性纳米粒子是磁性纳米粒子表面偶联特定的靶向配体，靶向性结合特定的肿瘤细胞。靶向配体的选择是提高主动靶向性的关键。主动靶向性提高了磁性纳米粒子在肿瘤组织内的浓度，减少对正常组织的毒性，从而使其在肿瘤成像与治疗成为可能。磁感应热疗利用磁介质在外加交变磁场的作用下感应发热，是一种新型的具有前景的肿瘤治疗手段。依靠磁性纳米粒子主动靶向性，磁感应热疗将更好地实现细胞内热疗，提高肿瘤治疗的疗效。

Active Targeting Magnetic Iron Oxide Nanoparticles:Current Status and Novel Applications in Tumor Hyperthermia

Magnetic nanoparticles are important tools in tumor imaging and therapy. However, low therapeutic concentration of the nanoparticles at the tumor sites has limited their clinical applications. Active targeting employs magnetic nanoparticles conjugated to specific ligands that selectively bind to biomarkers on target cells. Several receptor systems are overexpressed in cancerous diseases and have been investigated as targets for ligand-directed magnetic nanoparticles. The target receptors undergo repeated recycling between the cell surface and internalization, and bind to magnetic nanoparticles, thereby amplifying the magnetic signal for more precise diagnosis and treatment. This paper summarizes the recent advances in the development of active targeted magnetic iron oxide nanoparticles for tumor imaging and therapy. Magnetic nanoparticles with an alternating magnetic field can convert electromagnetic energy into heat and confine the heat to the tumor tissue. Magnetic fluid hyperthermia is a promising approach to cancer therapy because it not only directly kills cancer cells, but also indirectly activates anticancer immunity. Modifying the surface of magnetic nanoparticles to target specific molecules could improve their intracellular accumulation and their ability to target on tumor cells, and thus enhance their hyperthermia effects.