Iron oxide nanorods as a tool for the formation of tissue structures by magnetic field and laser irradiation

The use of magnetic nanorods under the action of a magnetic field or near-infrared laser radiation is a promising method for the formation of tissue structures. In particular, this is due to the high magnetisation of iron oxide-based nanorods and their low toxicity thanks to polymer coatings. The using of the thermal effect of laser exposure can solve the possibility of forming more complex tissue structures. The purpose of this study was the development of a method for the formation of tissue structures using nanorods under of magnetic fields and laser radiation in the near-infrared spectrum. Nanorods were prepared from Fe₃0₄ and coated with polyacrylic acid (Fe₃O₄@PAA). By transmission electron microscopy, the nanorods were characterized by an average thickness of 30 nm and an average length of 700 nm. The zeta potential of the particles: - 79 mV. The MTT test for cytotoxicity of the fibroblast cell line L929 was carried out and showed that the nanorods were non-toxic at concentrations ranging from 5-60 µg(Fe)/mL. IC50 was 135.7 µg/mL. After laser exposure (808 nm, 10 min) with dose of 31.5 µg(Fe)/mL Fe₃O₄@PAA MTT test showed almost total cell death. The data of double stained acridine orange and ethidium iodide confirmed the data of MTT test and showed that necrosis was the main cause of cell death after laser exposure. The possibility of forming cell structures by exposing cells with nanorods to a magnetic field has been shown. Thus, our synthesized Fe₃O₄@PAA could be used to form different cell structures from fibroblasts using a magnetic field, as well as changing the structure with near-infrared spectrum laser.