title: ZnFe2O4 nanoparticles as radiosensitizers in radiotherapy of human prostate cancer cells.
abstract: Nanoparticles of high-Z elements exhibit stronger photoelectric effects than soft tissues under gamma irradiation. Hence, they can be used as effective radiosensitizers for increasing the efficiency of current radiotherapy. In this work, superparamagnetic zinc ferrite spinel (ZnFe2O4) nanoparticles were synthesized by a hydrothermal reaction method and used as radiosensitizers in cancer therapy. The magnetic nanoparticles showed fast separation from solutions (e.g., ~1 min for 2 mg mL(-1) of the nanoparticles in ethanol) by applying an external magnetic field (~1T). The ZnFe2O4 nanoparticles were applied in an in vitro radiotherapy of lymph node carcinoma of prostate cells (as high radioresistant cells) under gamma irradiation of (60)Co source. The nanoparticles exhibited no significant effects on the cancer cells up to the high concentration of 100 μg mL(-1), in the absence of gamma irradiation. The gamma irradiation alone (2Gy dose) also showed no significant effects on the cells. However, gamma irradiation in the presence of 100 μg mL(-1) ZnFe2O4 nanoparticles resulted in ~53% inactivation of the cells (~17 times higher than the inactivation that occurred under gamma irradiation alone) after 24h. The higher cell inactivation was assigned to interaction of gamma radiation with nanoparticles (photoelectric effect), resulting in a high level electron release in the media of the radioresistant cells. Our results indicated that ZnFe2O4 nanoparticles not only can be applied in increasing the efficiency of radiotherapy, but also can be easily separated from the cell environment by using an external magnetic field after the radiotherapy.
authors.affiliation: Department of Physics, Payame Noor University (PNU), P.O. Box 19395-3697, Tehran, Iran; Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Meidanchi
authors.affiliation: Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran, Iran; Institute for Nanoscience and Nanotechnology, Sharif University of Technology, P.O. Box 14588-89694, Tehran, Iran. Electronic address: oakhavan@sharif.edu.
authors.forename: Omid
authors.initials: O
authors.lastname: Akhavan
authors.affiliation: Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Samideh
authors.initials: S
authors.lastname: Khoei
authors.affiliation: Department of Physics, Payame Noor University (PNU), P.O. Box 19395-3697, Tehran, Iran; Computational Physical Sciences Research Laboratory, School of Nano-Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), PO Box 19395-5531, Tehran, Iran.
authors.forename: Ali A
authors.initials: AA
authors.lastname: Shokri
authors.affiliation: Department of Medical Physics, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Hajikarimi
authors.affiliation: Department of Cardiology, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Nakisa
authors.initials: N
authors.lastname: Khansari
mesh_terms: D006801:Humans; D008297:Male; D053768:Metal Nanoparticles; D008855:Microscopy, Electron, Scanning; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use*
chemical_list: D011838:Radiation-Sensitizing Agents
keywords: Nanoparticles; Radioresistant cancer cells; Radiosensitizers; Radiotherapy; Zinc ferrite spinels