The development of noninvasive testing techniques in medicine by combining dual-mode Magnetic Resonance (MR)/ Computed Tomography (CT) imaging techniques will help overcome the limitations of the separated methods, leading to more accurate diagnoses. This has implications in clinical research, but currently remains a major challenge in terms of the need for a corresponding multimodal signal contrast agent. In this study, we use small size, monodispersed Fe₃O₄ magnetic nanoparticles as the seeds to synthesize magneto-plasmonic Fe₃O₄@Au hybrid nanoparticles (HNPs) with multiple functions with core-shell structures. The influence of the ratios of HAuCl₄ and oleyamine (OLA) precursors on the shape and size of the nanoparticles (NPs) was investigated. The HAuCl₄/OLA ratio of 0.2/1 is the optimal condition. The obtained NPs has an average size of 21.2 nm with a uniform spherical shape, high monodispersity. After the surface functionalization with poly(acrylic acid) (PAA), the resulting Fe₃O₄@Au@PAA HNPs showed excellent dispersion in water, good biocompatibility, non-toxicity against Hep-G2 cancer cell line and Vero healthy cell line at high test concentration. The In-vitro test data showed that the materials with Au shell enhance X-ray decrease even at low concentrations compared to iodine-based commercial substances while retaining the same effect as T₂ contrast agent with high transverse relaxation rate r₂ (125.2 mM⁻¹s⁻¹). The In-vivo MRI images of rat liver tissue demonstrated that the hybrid nanoparticles showed the contrast increases 3 times under 1.5 T magnetic field after 30 minutes of drug administration. The computed tomography measurements showed the highest Hounsfield unit (HU) of 133.5 after the hybrid nanoparticle injected for 30 minutes. The in-vivo efficacy of Fe₃O₄@Au@PAA magneto-plasmonic hybrid nanoparticles was further evaluated in the cardiac and renal organs in a mouse test model to study drug kinetics. Generally, these Fe₃O₄@Au@PAA hybrid nanomaterials showed great promise as a candidate for multi-modality molecular bio-imaging.

中文翻译：

---

用于双模式 MR/CT 成像应用的 Fe3O4-Au 混合纳米颗粒的分子成像对比度特性

通过结合双模式磁共振 (MR)/计算机断层扫描 (CT) 成像技术在医学中发展无创检测技术将有助于克服分离方法的局限性，从而实现更准确的诊断。这对临床研究有影响，但目前在需要相应的多模式信号造影剂方面仍然是一个主要挑战。在这项研究中，我们使用小尺寸、单分散的 Fe ₃ O ₄磁性纳米粒子作为种子来合成具有核壳结构的多功能磁等离子体 Fe ₃ O ₄ @Au 混合纳米粒子 (HNPs)。HAuCl ₄比例的影响研究了油胺 (OLA) 前体对纳米颗粒 (NP) 形状和尺寸的影响。0.2/1的HAuCl ₄ /OLA比率是最佳条件。获得的纳米颗粒平均粒径为 21.2 nm，球形均匀，单分散性高。用聚（丙烯酸）（PAA）表面功能化后，所得的 Fe ₃ O ₄ @Au@PAA HNPs 在水中表现出优异的分散性、良好的生物相容性、对 Hep-G2 癌细胞系和 Vero 健康细胞系的无毒性测试浓度高。在体外显示，与Au壳材料增强即使在低浓度相比，X射线降低测试数据基于碘的市售物质，同时保持相同的效果为T ₂具有高横向弛豫率r ₂ (125.2 mM ^-1 s ^-1 )的造影剂。的在体内大鼠肝组织的MRI图像显示，所述混合的纳米颗粒显示出对比度增加下1.5T的磁场3次给药后30分钟。计算机断层扫描测量显示，混合纳米颗粒注射 30 分钟后，最高的 Hounsfield 单位 (HU) 为 133.5。该被检体内的Fe功效₃ ö ₄ @ @的Au PAA磁-等离子体激元纳米颗粒混合在小鼠的试验模型以研究药物动力学的心脏和肾脏器官中进一步评估。通常，这些 Fe ₃ O ₄@Au@PAA 混合纳米材料作为多模态分子生物成像的候选材料显示出巨大的希望。