Zn doped iron oxide nanoparticles with high magnetization and photothermal efficiency for cancer treatment.

Magnetic nanoparticles (NPs) are powerful agents to induce hyperthermia in tumours upon the application of an alternating magnetic field or an infrared laser. Dopants have been investigated to alter different properties of materials. Herein, the effect of zinc doping into iron oxide NPs on their magnetic properties and structural characteristics has been investigated in-depth. A high temperature reaction with autogenous pressure was used to prepare iron oxide and zinc ferrite NPs of same size and morphology for direct comparison. Pressure was key in obtaining high quality nanocrystals with reduced lattice strain (27% less) and enhanced magnetic properties. Zn0.4Fe2.6O4 NPs with small size of 10.2 ± 2.5 nm and very high saturation magnetisation of 142 ± 9 emu gFe+Zn-1 were obtained. Aqueous dispersion of the NPs showed long term magnetic (up to 24 months) and colloidal stability (at least 6 d) at physiologically mimicking conditions. The samples had been kept in the fridge and had been stable for four years. The biocompatibility of Zn0.4Fe2.6O4 NPs was next evaluated by metabolic activity, membrane integrity and clonogenic assays, which show an equivalence to that of iron oxide NPs. Zinc doping decreased the bandgap of the material by 22% making it a more efficient photothermal agent than iron oxide-based ones. Semiconductor photo-hyperthermia was shown to outperform magneto-hyperthermia in cancer cells, reaching the same temperature 17 times faster whilst using 20 times less material (20 mgFe+Zn ml-1vs. 1 mgFe+Zn ml-1). Magnetothermal conversion was minimally hindered in the cellular confinement whilst photothermal efficiency remained unchanged. Photothermia treatment alone achieved 100% cell death after 10 min of treatment compared to only 30% cell death achieved with magnetothermia at clinically relevant settings for each at their best performing concentration. Altogether, these results suggest that the biocompatible and superparamagnetic zinc ferrite NPs could be a next biomaterial of choice for photo-hyperthermia, which could outperform current iron oxide NPs for magnetic hyperthermia.

Large-scale aqueous synthesis of Cu(In,Ga)Se2 nanoparticles for photocatalytic degradation of ciprofloxacin.

Environmentally friendly synthesis of Cu(In,Ga)Se2 (CIGS) nanoparticles (NPs) is pivotal for producing sustainable photocatalytic compounds to be applied in the remediation of contaminants of emerging concern from water. To this end, we herein report an aqueous synthesis of CIGS NPs, followed by annealing, to give access to phase-pure CIGS crystals with chalcopyrite structure and no signs of secondary phases. Morphological and compositional characterization revealed NPs with an average size of 10-35 nm and uniform distribution of Cu, In, Ga, and Se elements. In addition, the first aqueous large-scale synthesis of CIGS NPs is developed by up-scaling the synthesis procedure, resulting in 5 g of highly crystalline nanoparticles exhibiting an ideal optical band gap of 1.14 eV. The as-synthesized NPs proved the ability to remove 71 and 83% of a contaminant of emerging concern, ciprofloxacin (CIP), under ultraviolet (UV) and visible (Vis) radiations, respectively.