Biointeractions of Mn-doped citrate-coated magnetite nanoparticles with HeLa cells: A cytotoxic evaluation

Magnetic nanoparticles (NPs) form a category of NPs that can be easily manipulated with a magnetic field. In the present study, superparamagnetic magnetite (Fe 3 O 4 ) NPs (MNPs) doped with manganese (Mn 2+) and coated with citric acid (CA) were synthesised via a cost-effective and simple co-precipitation method. The obtained nano powder was investigated using X-ray powder diffraction (XRD) spectroscopy, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM), UV–visible (UV–Vis) spectroscopy, and vibrating sample magnetometer (VSM). These analyses validate the successful integration of Mn 2+ ions into the magnetite structure, with only a minor effect on the lattice parameter value. Spectroscopic investigations revealed the composition of MNPs and the coating with citrate ions. Magnetic measurements confirmed that the synthesised MNPs exhibit superparamagnetic characteristics, displaying minimal remanence and coercivity. The cytotoxic effects were evaluated on HeLa cells using the MTT assay at concentrations ranging from 50 to 300 μg/mL. The results revealed a dose-dependent cytotoxicity for all MNPs combinations. Additionally, findings indicate that surface functionalization and ion doping significantly affect the biocompatibility of MNPs and enhance their potential for biomedical applications. • Mn-doped Fe 3 O 4 nanoparticles synthesised via co-precipitation with Mn 2+ substitution and citric acid coating. • Structural and optical properties studied using XRD, FTIR, SEM, UV–Vis, and Raman spectroscopy. • VSM measurements reveal superparamagnetic behaviour with high saturation magnetisation and negligible coercivity. • Cytotoxicity was assessed using the MTT assay on HeLa cells at concentrations ranging from 50 to 300 μg/mL. • Mn 2+ -doped, citrate-coated Fe 3 O 4 maintained over 85 % cell viability at 300 μg/mL after 24 h.