Siti Fatimah Azzahro, Adhistinka Jiananda, Dyah Ayu Larasati, Mahardika Yoga Darmawan, Emi Kurnia Sari, Nurul Imani Istiqomah, Daiki Oshima, Takeshi Kato, Edi Suharyadi
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, C[dbnd]C, 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. © 2025 Elsevier B.V.
Department of Physics, Universitas Gadjah Mada, Sekip Utara BLS 21 Yogyakarta, Indonesia; Department of Physics, Institut Teknologi Sumatera, Terusan Ryacudu, Way Hui, Jati Agung, Lampung, Indonesia; Department of Electronics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan; Institute of Materials and Systems for Sustainibility, Furo-cho, Chikusa-ku, Nagoya University, Nagoya, Japan