The influence of magnetic and physiological behaviour on the effectiveness of iron oxide nanoparticles for hyperthermia
The influence of magnetic and physiological behaviour on the effectiveness of iron oxide nanoparticles for hyperthermia
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DOI：
10.1088/0022-3727/41/13/134020
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发表时间：
2008-07-07
影响因子：
3.4
通讯作者：
Gruettner, C.
中科院分区：
文献类型：
--
作者：
Dennis, C. L.;Jackson, A. J.;Gruettner, C.
磁性纳米颗粒正在开发用于广泛的生物医学应用。特别地，热疗涉及通过暴露于交变磁场来加热磁性纳米颗粒。这些材料提供了通过局部和细胞水平加热癌症组织来选择性治疗癌症的潜力。如果肿瘤中有足够的颗粒，具有足够高的比吸收率（SAR），可以快速存款热量，同时最大限度地减少对周围组织的热损伤，那么这可能是一种成功的方法。高SAR磁性纳米颗粒已被开发并用于小鼠癌症模型。磁性纳米颗粒包含被葡聚糖层壳包围的氧化铁磁性核（平均核直径为50 nm），用于胶体稳定性。在比较两个类似的系统中，饱和磁化强度被发现在确定SAR中起着至关重要的作用，但不是唯一的重要因素。（在1080 Oe和150 kHz时，饱和磁化强度的差异为1.5倍，SAR的差异为2.5倍。）由于葡聚糖层的差异，通过中子散射确定的相互作用的变化，也发挥了作用的SAR。一旦这些纳米颗粒被引入肿瘤中，其关于肿瘤生长的功效就由纳米颗粒在肿瘤细胞内或附近的位置以及纳米颗粒与递送的交变磁场（AMF）的关联来确定。这种关联（纳米颗粒SAR和AMF）决定了产生的热量。在我们的设置中，产生的热量和加热时间（热剂量）提供了与常规（非纳米颗粒）热疗密切相关的肿瘤总体治疗反应。也就是说，纳米颗粒热疗细胞病理学机制的具体方面可能与传统癌症治疗热疗中观察到的非常不同。
Magnetic nanoparticles are being developed for a wide range of biomedical applications. In particular, hyperthermia involves heating the magnetic nanoparticles through exposure to an alternating magnetic field. These materials offer the potential to selectively treat cancer by heating cancer tissue locally and at the cellular level. This may be a successful method if there are enough particles in a tumor possessing a sufficiently high specific absorption rate (SAR) to deposit heat quickly while minimizing thermal damage to surrounding tissue. High SAR magnetic nanoparticles have been developed and used in mouse models of cancer. The magnetic nanoparticles comprise iron oxide magnetic cores (mean core diameter of 50 nm) surrounded by a dextran layer shell for colloidal stability. In comparing two similar systems, the saturation magnetization is found to play a crucial role in determining the SAR, but is not the only factor of importance. (A difference in saturation magnetization of a factor of 1.5 yields a difference in SAR of a factor of 2.5 at 1080 Oe and 150 kHz.) Variations in the interactions due to differences in the dextran layer, as determined through neutron scattering, also play a role in the SAR. Once these nanoparticles are introduced into the tumor, their efficacy, with respect to tumor growth, is determined by the location of the nanoparticles within or near the tumor cells and the association of the nanoparticles with the delivered alternating magnetic field (AMF). This association (nanoparticle SAR and AMF) determines the amount of heat generated. In our setting, the heat generated and the time of heating (thermal dose) provides a tumor gross treatment response which correlates closely with that of conventional (non-nanoparticle) hyperthermia. This being said, it appears specific aspects of the nanoparticle hyperthermia cytopathology mechanism may be very different from that observed in conventional cancer treatment hyperthermia.