Low toxicity superparamagnetic magnetite nanoparticles: One-pot facile green synthesis for biological applications

- Uniform magnetite nanoparticles coated with PVA was synthesized.
- It was not necessary to use a special atmosphere during the synthesis.
- The expected superparamagnetic behavior was confirmed.
- Coated nanoparticles exhibited low cytotoxicity against BHK lines.
- Preliminary assessment of nanoparticles in vivo effects were investigated.

Superparamagnetic magnetite nanoparticles have been synthesized by a highly reproducible polyvinyl alcohol (PVA)-based modified sol-gel process using water as the only solvent. The synthesis method has proven to be effective, time and cost saving and environmental friendly, resulting in PVA-coated magnetite nanoparticles as direct product from the synthesis, without any special atmosphere or further thermal treatment. X-ray diffraction and transmission electron microscopy revealed that the biocompatible PVA-coating prevents the nanoparticle agglomeration, giving rise to spherical crystals with sizes of 6.8 nm (as-cast) and 9.5 nm (heat treated) with great control over size and shape with narrow size distribution. Complementary compositional and magnetic characterizations were employed in order to study the surface chemistry and magnetic behavior of the samples, respectively. Cytotoxicity endpoints including no observed adverse effect concentration (NOAEC), 50% lethal concentration (LC50) and total lethal concentration (TLC) of the tested materials on cell viability were determined after 3, 24 and 48 h of exposure. The PVA coating improved the biocompatibility of the synthesized magnetite nanoparticles showing good cell viability and low cytotoxicity effects on the MTT assay performed on BHK cells. Preliminary assessment of nanoparticles in vivo effects, performed after 48 h on Balb/c mice, exposed to a range of different sub-lethal doses, showed their capacity to penetrate in liver and kidneys with no significant morphological alterations in both organs.