Highly biocompatible superparamagnetic Ni nanoparticles dispersed in submicron-sized C spheres

Magnetic nanoparticles (NPs) have attracted considerable interest due to their promising potential applications in the early-stage diagnosis and therapy of the cancer diseases. Here, we synthesized highly biocompatible spheres of Ni@C composite using the radio frequency plasma enhanced chemical vapor deposition technique. The synthesized composite is in novel geometry where each sphere (submicron in size) consists of C colloid containing inside a randomly dispersed set of Ni NPs (average diameter 6.5 ± 1 nm). The Ni NPs are tightly embedded in the C sphere and well protected from oxidation. Because of its magnetic properties (high saturation magnetization and zero coercivity) the composite is rendered very promising for clinical applications. Its biocompatibility has been tested in vitro in non-malignant fibroblasts and malignant prostate cancer cells. Using a set of different cytotoxicity assays, the magnetic Ni NPs exhibit no acute toxicity in both cells types. These results suggest that the synthesized Ni@C spheres are highly biocompatible at least in vitro and might therefore be suitable for further in vivo feasibility studies for biomedical applications.