Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Universitat de Barcelona, Avda Joan XXIII, 27-31, 08028 Barcelona, Catalonia, Spain.
Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028 Barcelona, Catalonia, Spain.
Molecules. 2020 Nov 14;25(22):5315. doi: 10.3390/molecules25225315.
Superparamagnetic nanoparticles (iron oxide nanoparticles-IONs) are suitable for hyperthermia after irradiating with radiofrequency radiation. Concerning the suitability for laser ablation, IONs present a low molar absorption coefficient in the near-infrared region close to 800 nm. For this reason, they are combined with other photothermal agents into a hybrid composite. Here, we show that IONs absorb and convert into heat the infrared radiation characteristic of the so-called second-biological window (1000-1350 nm) and, in consequence, they can be used for thermal ablation in such wavelengths. To the known excellent water solubility, colloidal stability and biocompatibility exhibited by IONs, an outstanding photothermal performance must be added. For instance, a temperature increase of 36 °C was obtained after irradiating at 8.7 W cm for 10 min a suspension of IONs at iron concentration of 255 mg L. The photothermal conversion efficiency was ~72%. Furthermore, IONs showed high thermogenic stability during the whole process of heating/cooling. To sum up, while the use of IONs in the first bio-window (700-950 nm) presents some concerns, they appear to be good photothermal agents in the second biological window.
超顺磁纳米颗粒（氧化铁纳米颗粒 - IONs）在接受射频辐射后适合用于热疗。就激光烧蚀的适用性而言，IONs 在接近 800nm 的近红外区域表现出低摩尔吸收系数。出于这个原因，它们与其他光热试剂结合成一种混合复合材料。在这里，我们展示了 IONs 吸收并转化为热红外辐射，其特征在于所谓的第二生物窗口（1000-1350nm），因此它们可用于此类波长的热消融。除了 IONs 已经表现出的出色的水溶性、胶体稳定性和生物相容性外，还必须添加出色的光热性能。例如，在将浓度为 255mg/L 的 IONs 悬浮液以 8.7W/cm 的功率照射 10 分钟后，可获得 36°C 的温度升高。光热转换效率约为 72%。此外，IONs 在整个加热/冷却过程中表现出很高的热生成稳定性。总之，虽然在第一生物窗口（700-950nm）中使用 IONs 存在一些问题，但它们似乎是第二生物窗口中的良好光热试剂。
