Enhanced magnetic hyperthermia of green-synthesized CoFe2O4/C-dots nanocomposites utilizing moringa oleifera extract and watermelon peels

Abstract

This research focuses on cobalt ferrite (CoFe₂O₄)/carbon dots (C-dots) nanocomposites synthesized through green synthesis, utilizing Moringa oleifera leaf extract and watermelon rind waste for magnetic hyperthermia applications in cancer therapy, enabling targeted and localized heating. CoFe₂O₄ nanoparticles were synthesized via a co-precipitation method, while the C-dots were produced hydrothermal. Sonication was applied to connect the C-dots to the surface of CoFe₂O₄. The X-ray diffraction spectrum of CoFe₂O₄/C-dots shows a cubic spinel structure with crystallite sizes ranging from 7.6 nm to 6.2 nm, where the crystallite size decreases with increasing C-dots concentration. Transmission electron microscopy observations reveal that the size of the nanocomposites is almost consistent at around 11.8–12.1 nm. The Co–O and Fe–O functional groups detected in the nanocomposite indicate that CoFe₂O₄ remains after fabrication. The identified C–O, CC, and O–H groups also confirm the presence of C-dots on the CoFe₂O₄ surface. The UV–Vis absorption spectrum peaks at 282 nm for C-dots and 218 nm for CoFe₂O₄. The addition of C-dots affects the saturation magnetization and domain size, which are 55–56.4 emu/g and 3.2–3.5 nm, indicating good magnetic properties. Additionally, the specific absorption rate (SAR) value of CoFe₂O₄/C-dots depends on magnetization, with the SAR value decreasing with increasing C-dots concentration while increasing with higher frequency and alternating magnetic field. The highest SAR values for CoFe₂O₄ and CoFe₂O₄/C-dots are 626 mW/g and 485 mW/g, respectively, which decrease with an increase in C-dots concentration. These results indicate that CoFe₂O₄/C-dots synthesized using green methods are promising candidates that can optimize performance in magnetic hyperthermia applications in the future.