Purpose: Nanotechnology applied to cancer treatment is a growing area of research in nanomedicine with magnetic nanoparticle-mediated anti-cancer drug delivery systems offering least possible side effects. To that end, both structural and chemical properties of commercial cobalt metal nanoparticles were studied using label-free confocal Raman spectroscopy.
Materials and Methods: Crystal structure and morphology of cobalt nanoparticles were studied by XRD and TEM. Magnetic properties were studied with SQUID and PPMS. Confocal Raman microscopy has high spatial resolution and compositional sensitivity. It, therefore, serves as a label-free tool to trace nanoparticles within cells and investigate the interaction between coating-free cobalt metal nanoparticles and cancer cells. The toxicity of cobalt nanoparticles against human cells was assessed by MTT assay.
Results: Superparamagnetic Co metal nanoparticle uptake by MCF7 and HCT116 cancer cells and DPSC mesenchymal stem cells was investigated by confocal Raman microscopy. The Raman nanoparticle signature also allowed accurate detection of the nanoparticle within the cell without labelling. A rapid uptake of the cobalt nanoparticles followed by rapid apoptosis was observed. Their low cytotoxicity, assessed by means of MTT assay against human embryonic kidney (HEK) cells, makes them promising candidates for the development of targeted therapies. Moreover, under a laser irradiation of 20mW with a wavelength of 532nm, it is possible to bring about local heating leading to combustion of the cobalt metal nanoparticles within cells, whereupon opening new routes for cancer phototherapy.
Conclusion: Label-free confocal Raman spectroscopy enables accurately localizing the Co metal nanoparticles in cellular environments. The interaction between the surfactant-free cobalt metal nanoparticles and cancer cells was investigated. The facile endocytosis in cancer cells shows that these nanoparticles have potential in engendering their apoptosis. This preliminary study demonstrates the feasibility and relevance of cobalt nanomaterials for applications in nanomedicine such as phototherapy, hyperthermia or stem cell delivery.

Keywords: Raman spectroscopy, cobalt nanoparticles, cancer cells, stem cells, cellular uptake, apoptosis, label-free tool


中文翻译：

---

使用实时拉曼光谱评估癌细胞对钴金属纳米颗粒的吸收

目的：应用于癌症治疗的纳米技术是纳米医学研究的一个不断发展的领域，其磁性纳米粒子介导的抗癌药物递送系统可提供最少的副作用。为此，使用无标记共焦拉曼光谱研究了商业钴金属纳米粒子的结构和化学性质。
材料和方法：采用XRD和TEM研究了钴纳米颗粒的晶体结构和形貌。用 SQUID 和 PPMS 研究磁性。共焦拉曼显微镜具有高空间分辨率和成分灵敏度。因此，它可以作为一种无标记工具来追踪细胞内的纳米颗粒，并研究无涂层钴金属纳米颗粒与癌细胞之间的相互作用。通过MTT法评估钴纳米颗粒对人体细胞的毒性。
结果：通过共聚焦拉曼显微镜研究了 MCF7 和 HCT116 癌细胞和 DPSC 间充质干细胞对超顺磁性 Co 金属纳米颗粒的摄取。拉曼纳米粒子特征还允许在不标记的情况下准确检测细胞内的纳米粒子。观察到钴纳米颗粒的快速吸收，然后是快速细胞凋亡。通过针对人胚胎肾 (HEK) 细胞的 MTT 测定法评估它们的低细胞毒性，使它们成为开发靶向疗法的有希望的候选者。此外，在20mW、532nm波长的激光照射下，可产生局部加热，使钴金属纳米粒子在细胞内燃烧，从而为癌症光疗开辟新的途径。
结论：无标记共焦拉曼光谱能够在细胞环境中准确定位钴金属纳米颗粒。研究了不含表面活性剂的钴金属纳米粒子与癌细胞之间的相互作用。癌细胞中的易内吞作用表明这些纳米颗粒具有引起其凋亡的潜力。这项初步研究证明了钴纳米材料在纳米医学中应用的可行性和相关性，例如光疗、热疗或干细胞输送。

关键词：拉曼光谱，钴纳米粒子，癌细胞，干细胞，细胞摄取，细胞凋亡，免标记工具