Size and shape-dependent effects of the iron oxide nanoparticles in biomedical applications: T2-relaxation, hyperthermia, magnetic properties and cytotoxicity

Magnetic nanoparticles (MNP) attract particular interest for usage in different  biomedical branchs, such as targeted drug delivery, magnetic resonance imaging and magnetic hyperthermia. Widespread use of magnetite... [ view full abstract ]

Magnetic nanoparticles (MNP) attract particular interest for usage in different  biomedical branchs, such as targeted drug delivery, magnetic resonance imaging and magnetic hyperthermia. Widespread use of magnetite nanoparticles in biomedicine became possible due to their magnetic properties, low toxicity and biodegradability. It is also known that the shape and size of the MNP can affect their magnetic and structural properties. Thus the aim of the study is to reveal the effect of particles shape on magnetic and contrast properties and cytotoxicity towards the PC3 and LNCaP prostate cancer cell lines.

The following forms of particles were obtained by method of high-temperature thermal decomposition: spherical, cubic, octahedral, hexagonal and tetragonal prisms, plates. X-ray phase analysis confirmed the presence of the inverse spinel phase in all samples.

The cytotoxicity of nanoparticles has been tested on human PC3 and LNCaP cell lines. Cell survival with the addition of MNP suspensions in concentration varying from 2.5 to 50 μg/ml was 80-100%, except octahedral and cubic particles, which demonstrated slightly higher cytotoxicity on LNCaP culture.

Temperature change measurements of MNP suspensions from the exposition time under an external magnetic field (H = 95 Oe, f = 100 kHz) resulted in the following values of the temperature: nanoplates - 99° C, hexagonal prisms - 60° C, spheres - 41° C, octahedrons - 40° C.

It was shown that the hexagonal prisms possess the greatest coercive force and saturation magnetization. Nanoplates of the smallest size had low toxicity and the highest T2-contrast, which makes them promising MNP for targeted drug delivery and MRI. They also showed higher heating temperature under magnetic field and can find application in hyperthermia.

The authors gratefully acknowledge the support of the Ministry of Education and Science of the Russian Federation (grant № 14.578.21.0201 (RFMEFI57816X0201)).