Inorganic Chemistry Communications 145 (2022) 110000 Available online 16 September 2022 1387-7003/© 2022 Elsevier B.V. All rights reserved. Short communication Synthesis and investigation of hyperthermia properties of Fe 3 O 4 /HNTs magnetic nanocomposite Sajjad Tabar Maleki * , Seyed Javad Sadati Department of Physics, Iran University of Science and Technology, Tehran 16846–13114, Iran A R T I C L E INFO Keywords: Fe 3 O 4 Halloysite nanotube Magnetic nanoparticles SAR Hyperthermia ABSTRACT In this study, combining magnetic nanoparticles with halloysite nanotubes (HNTs), Fe 3 O 4 / HNTs nano- composites were synthesized using the co-precipitation method. The synthesized nanocomposites were charac- terized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), Thermogravimetric analysis (TGA), energy-dispersive Xray (EDX) analysis, vibrating sample magnetometer (VSM). At room temperature, the saturation magnetization (M S ) showed that Fe 3 O 4 and Fe 3 O 4 / HNTs nano- particles have a magnetic saturation of 73.84 emu/g and 30.63 emu/g, respectively. The maximum specifc absorption rates (SARs) obtained for Fe 3 O 4 / HNTs nanocomposites were 94 w/g at a frequency of 400 kHz and 53 w/g at a frequency of 200 kHz, respectively. The results show that Fe 3 O 4 / HNTs nanocomposites are desirable in the application of hyperthermia to treat cancer. 1. Introduction According to reports published in 2018 by the World Health Orga- nization, cancer incidence has increased worldwide due to rapid lifestyle changes [1]. One way to treat cancer in which magnetic nanoparticles (MNPs) enter tumor tissue is magnetic fuid hyperthermia (MFH). MNPs generate heat by exposure to an alternating external magnetic feld. The heat generated by increasing the temperature of tumor tissue leads to damage or death of cancer cells with the least amount of side effects on healthy tissues [2,3]. In 1957, Gilchrist and colleagues frst studied the use of MNPs in cancer treatment [4]. The induction heating effciency of MNPs is measured in terms of SAR. SAR is essential for the clinical ap- plications of MNPs and should be as high as possible because the higher the SAR, the fewer nanoparticles that should be injected into the pa- tient’s cancerous tissue. MNPs for hyperthermic applications must have specifc characteristics such as biocompatibility with low cytotoxicity, appropriate nanoparticle size (N.P.s), and SAR within the tolerable human range [5,6]. Researchers have extensively investigated the sur- face modifcation of magnetic nanoparticles, their composition, shape, and the effects of particle size on the amount of SAR in recent years [7–11]. Among magnetic nanoparticles, magnetite (Fe 3 O 4 ) is the most commonly used material in magnetic hyperthermia experiments due to its chemical stability [12], magnetization and advanced sensitivity [13], and biocompatibility [14]. Magnetic properties can be changed by changing the structure, size, and morphology of Fe 3 O 4 nanoparticles. The morphology of Fe 3 O 4 is complicated to control due to the complexity of its inherent inverse spinel structure [15]. Modifying the surface of MNPs with biocompatible materials is desirable to achieve colloidal dispersion [16]. These biocompatible surface coatings can provide an outer protective layer on the surface of MNPs to facilitate proper binding to surface receptors in tumor sites [17]. Halloysite nanotubes (HNTs) include low toxicity structure, green properties, high thermal and mechanical stability, and microporous properties [18]. HNTs with rod geometry and non-intertwined properties are easily dispersed in solutions or polymer matrices [19]. HNTs are naturally occurring aluminosilicate clay minerals with promising applications in many high-tech felds. HNTs have a mainly hollow tubular structure with a diameter of 50–70 nm and a length of 200–1000 nm. HNTs are a dominant mineral in newly formed volcanic ash soil and the early weathering product of lateritic soil, widespread worldwide. HNTs are created by rolling up the kaolinite plates, so they have a formula of Al 2 Si 2 O 5 (OH) 4 ⋅nH 2 O similar to kaolinite [20]. The structure of HNTs features a main tubular morphology with the Al-OH layer composing inside the tubes and the Si-O outside. Due to the empty tubular structure, HNTs have been recognized as a ‘green’ and environmentally available container for encapsulation of active agents in the area application of medical and chemical industries. The advantages of HNTs include elongated shape, empty lumen, high adsorption ability, ease of * Corresponding author. E-mail address: S_tabarmaleki@physics.iust.ac.ir (S. Tabar Maleki). Contents lists available at ScienceDirect Inorganic Chemistry Communications journal homepage: www.elsevier.com/locate/inoche https://doi.org/10.1016/j.inoche.2022.110000 Received 12 July 2022; Received in revised form 5 September 2022; Accepted 11 September 2022