Background Cancer remains as one of the major causes of mortality worldwide. Recent advances in nanoparticles based therapy mark a new era on cancer treatment. Many groups have investigated biological/physical effects of nanoparticles on tumour cells and how these vary with physical parameters such as particle size, shape, concentration and distribution. Magnetic hyperthermia (MHT) can be an alternative or an add-value therapy with demonstrated effectiveness. MHT uses magnetic nanoparticles, which can be directly applied to the tumour, where, by applying an external ac magnetic field, will promote a localized temperature increment that can be controlled. Methods LiFe5O8 nanocrystallites were synthesized by a novel and eco-friendly sol-gel process, using powder coconut water (PCW) has a mediated reaction medium. The dried powders were heat-treated between 400 and 1000 °C, being analysed their structure, morphology and magnetic properties; cytotoxicity and magnetic hyperthermia assays were performed. Results The heat-treated LiFe5O8 powder led to crystallite sizes from 50 nm to 200 nm. Increasing the temperature of the heat treatment, secondary phases tend to disappear. The cytotoxicity results revealed a non-cytotoxicity property, for concentrations below 5 mg/mL. The sample HT at 1000 °C, revealed hysteresis and magnetic saturation of 73 emu.g−1 at 300 K and a specific absorption rate(SAR) of about 80 W/g. Conclusions It was possible to synthesize LiFe5O8 by a novel, eco-friendly and sustainable route. The nanoparticles have a high heat efficiency, especially the sample heat-treated at 1000 °C, with SAR values similar to Fe3O4, showing potential to be used in the treatment of cancer, by MHT.

中文翻译：

---

用于磁热疗的纳米材料

背景癌症仍然是全世界死亡的主要原因之一。基于纳米粒子的治疗的最新进展标志着癌症治疗的新时代。许多研究小组已经研究了纳米粒子对肿瘤细胞的生物/物理影响，以及这些影响如何随物理参数（如粒径、形状、浓度和分布）而变化。磁热疗 (MHT) 可以作为一种替代疗法或增值疗法，并已证明其有效性。MHT 使用磁性纳米粒子，可以直接应用于肿瘤，通过施加外部交流磁场，将促进可以控制的局部温度升高。方法以粉末椰子水（PCW）为介导反应介质，采用新型环保溶胶-凝胶工艺合成LiFe5O8纳米微晶。将干燥后的粉末在400～1000℃之间进行热处理，分析其结构、形貌和磁性；进行了细胞毒性和磁热疗测定。结果热处理的LiFe5O8 粉末导致晶粒尺寸从50 nm 到200 nm。提高热处理温度，第二相趋于消失。对于低于 5 mg/mL 的浓度，细胞毒性结果显示非细胞毒性特性。样品 HT 在 1000 °C 时，在 300 K 时的磁滞和磁饱和度为 73 emu.g-1，比​​吸收率 (SAR) 约为 80 W/g。结论通过新颖、环保、可持续的路线合成LiFe5O8是可能的。纳米粒子具有很高的热效率，特别是在 1000 ℃热处理的样品，其 SAR 值与 Fe3O4 相似，