Plasma-enhanced CVD synthesis and cytotoxic evaluation of graphitic carbon embedded - Fe₃O₄ nanoparticles

This study reports the synthesis of graphitic carbon embedded - Fe₃O₄ nanoparticles using a novel method that enables a low-temperature rapid process and includes cytotoxicity tests to evaluate their potential use in biomedical applications. In this study, graphitic carbon was grown on Fe₃O₄ core using a plasma-enhanced chemical vapor deposition (PE-CVD) system under an Ar-H₂-CH₄ gas plasma at 650 °C for 15 min. X-ray diffractometry (XRD) and Raman spectroscopy investigations confirmed that Fe₃O₄ nanoparticles were embedded in graphitic carbon (Fe₃O₄@C). Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), along with transmission electron microscopy (TEM) equipped with EDS, also supported the carbon formation and nano-sized structure of the synthesized particles. Fe₃O₄@C nanoparticles exhibited soft magnetic properties with saturation magnetization (M_s) and coercivity (H_c) values of 69.27 emu/g and 97 Oe, respectively. Cytotoxicity assessment on HeLa and MCF7 cancer cells suggested biocompatibility at and below a dose of 100 μg/mL after 24 h of exposure but a drop in cell viability at higher doses and longer incubation times, more on cancer cell lines than the healthy L929 cells. These results suggest that Fe₃O₄@C nanoparticles might be potential candidates for biomedical applications, including drug delivery, photothermal therapy, and magnetically-triggered operations.