在一种生物相容性纳米制剂中将光热和磁性功能结合起来，为生物医学治疗诊断的多功能药剂的开发提供了有吸引力的基础。在这里，我们报道了使用飞秒激光在丙酮中从硅和铁混合靶材制备用于治疗诊断的硅铁（Si-Fe）复合纳米粒子（NPs）的方法。随后将NPs转移到水中以进行生物学。从结构分析中可以看出，形成的Si-Fe NPs具有球形和尺寸从5到150 nm的范围，大小分布中存在两个特征最大值，分别约为 20 nm和90 nm。它们主要由硅组成，并且存在显著的硅化铁含量和铁氧体夹杂物。我们的研究还表明，NPs由于其组成中存在铁离子而表现出磁性，这使得磁共振成像（MRI）中的对比度形成成为可能，这一点通过质子共振频率的磁共振松弛度验证。此外，Si-Fe NPs在生物组织相对透明窗口（650-950 nm）处具有强光吸收特性。受益于这种吸收，Si-Fe NPs在808 nm连续波激光激发下，能够在其水悬浮液中提供强热效应。由NP诱导的光热效应以光热转化效率33-42%进行描述，比纯光合合成的Si NPs大约高出3.0-3.3倍，这是由于NP组分中存在硅化铁所解释。结合强光热效应和MRI功能，合成的Si-Fe NPs为癌症治疗诊断的方法提供了重要的进展，包括磁共振成像引导的光热疗法和手术。

The combination of photothermal and magnetic functionalities in one biocompatible nanoformulation forms an attractive basis for developing multifunctional agents for biomedical theranostics. Here, we report the fabrication of silicon-iron (Si-Fe) composite nanoparticles (NPs) for theranostic applications by using a method of femtosecond laser ablation in acetone from a mixed target combining silicon and iron. The NPs were then transferred to water for subsequent biological use. From structural analyses, it was shown that the formed Si-Fe NPs have a spherical shape and sizes ranging from 5 to 150 nm, with the presence of two characteristic maxima around 20 nm and 90 nm in the size distribution. They are mostly composed of silicon with the presence of a significant iron silicide content and iron oxide inclusions. Our studies also show that the NPs exhibit magnetic properties due to the presence of iron ions in their composition, which makes the formation of contrast in magnetic resonance imaging (MRI) possible, as it is verified by magnetic resonance relaxometry at the proton resonance frequency. In addition, the Si-Fe NPs are characterized by strong optical absorption in the window of relative transparency of bio-tissue (650-950 nm). Benefiting from such absorption, the Si-Fe NPs provide strong photoheating in their aqueous suspensions under continuous wave laser excitation at 808 nm. The NP-induced photoheating is described by a photothermal conversion efficiency of 33-42%, which is approximately 3.0-3.3 times larger than that for pure laser-synthesized Si NPs, and it is explained by the presence of iron silicide in the NP composition. Combining the strong photothermal effect and MRI functionality, the synthesized Si-Fe NPs promise a major advancement of modalities for cancer theranostics, including MRI-guided photothermal therapy and surgery.