Chen Hongwei, Burnett Joseph, Zhang Fuxiang, Zhang Jiaming, Paholak Hayley, Sun Duxin
Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, 428 Church Street,, Ann Arbor, Michigan 48109, USA.
J Mater Chem B. 2014 Feb 21;2(7):757-765. doi: 10.1039/c3tb21338b. Epub 2013 Dec 11.
We report that highly crystallized iron oxide nanoparticles (HCIONPs) made by thermal decomposition and further coating with a polysiloxane-containing copolymer can be used as effective mediators for photothermal therapy. Irradiation of a HCIONP solution containing 0.5 mg mL Fe, for instance, with an 885 nm diode laser at a power of 2.5 W cm, induces a temperature increase of 33 °C from room temperature, while water produced only a ∼3 °C increase as the control. In vivo studies are further evaluated for effective photothermal therapy using the as-prepared HCIONPs. Benefiting from the great antibiofouling property of the polymer coating and minimized hydrodynamic size (whole particle size: 24 nm), the nanoparticles intravenously administered to SUM-159 tumor-bearing mice can effectively accumulate within the tumor tissue (5.3% of injection dose) through the enhanced permeability and retention effect. After applying the same laser conditions to irradiate the tumors, complete tumor regression is observed within three weeks without disease relapse over the course of three months. Conversely, control mice exhibit continuous tumor growth leading to animal mortality within four weeks. To better understand the photothermal effect of HCIONPs and potentially improve their photothermal efficiency, we compare their photothermal effect and crystal structures with commercially available magnetic nanoparticles. Our data show that after applying the same laser to commercially available magnetic nanoparticles from FeREX at the same iron concentration, the temperature is only increased by 7.4 °C. We further use synchrotron-XRD and high-resolution TEM to compare the crystal structures of both magnetic nanoparticles. The data show that both magnetic nanoparticles are FeO but as-prepared HCIONPs are highly crystalline and have preferred lattice plane orientations, which may be the cause of their enhanced photothermal efficiency. Taken together, these data suggest that HCIONPs, with unique lattice orientations and small size as well as antifouling coating, can be used as promising mediators for photothermal cancer therapy.
我们报道，通过热分解制备并进一步用含聚硅氧烷的共聚物包覆的高度结晶的氧化铁纳米颗粒（HCIONPs）可作为光热疗法的有效介质。例如，用功率为2.5 W/cm²的885 nm二极管激光照射含有0.5 mg/mL Fe的HCIONP溶液，会使温度从室温升高33°C，而作为对照的水仅使温度升高约3°C。使用所制备的HCIONPs对有效的光热疗法进行了进一步的体内研究评估。得益于聚合物涂层的优异抗生物污损性能和最小化的流体动力学尺寸（整体粒径：24 nm），静脉注射到荷SUM-159肿瘤小鼠体内的纳米颗粒可通过增强的渗透和滞留效应有效地在肿瘤组织内蓄积（注射剂量的5.3%）。在应用相同的激光条件照射肿瘤后，在三周内观察到肿瘤完全消退，在三个月的过程中无疾病复发。相反，对照小鼠的肿瘤持续生长，导致四周内动物死亡。为了更好地理解HCIONPs的光热效应并潜在地提高其光热效率，我们将它们的光热效应和晶体结构与市售磁性纳米颗粒进行了比较。我们的数据表明，在相同铁浓度下对来自FeREX的市售磁性纳米颗粒应用相同的激光后，温度仅升高7.4°C。我们进一步使用同步加速器-X射线衍射（synchrotron-XRD）和高分辨率透射电子显微镜（high-resolution TEM）来比较两种磁性纳米颗粒的晶体结构。数据表明，两种磁性纳米颗粒均为Fe₃O₄，但所制备的HCIONPs是高度结晶的且具有择优晶格平面取向，这可能是它们光热效率增强的原因。综上所述，这些数据表明，具有独特晶格取向、小尺寸以及防污涂层的HCIONPs可作为光热癌症治疗的有前景介质。
