No abstract

Magnetic Fe3O4 nanoparticles (NPs) and their surface modification with therapeutic substances are of great interest, especially drug delivery for cancer therapy, including boron-neutron capture therapy (BNCT). In this paper, we present the results of boron-rich compound (carborane borate) attachment to previously aminated by (3-aminopropyl)-trimethoxysilane (APTMS) iron oxide NPs. Fourier transform infrared spectroscopy with Attenuated total reflectance accessory (ATR-FTIR) and energy-dispersive X-ray analysis confirmed the change of the element content of NPs after modification and formation of new bonds between Fe3O4 NPs and the attached molecules. Transmission (TEM) and scanning electron microscopy (SEM) showed Fe3O4 NPs’ average size of 18.9 nm. Phase parameters were studied by powder X-ray diffraction (XRD), and the magnetic behavior of Fe3O4 NPs was elucidated by Mössbauer spectroscopy. The colloidal and chemical stability of NPs was studied using simulated body fluid (phosphate buffer—PBS). Modified NPs have shown excellent stability in PBS (pH = 7.4), characterized by XRD, Mössbauer spectroscopy, and dynamic light scattering (DLS). Biocompatibility was evaluated in-vitro using cultured mouse embryonic fibroblasts (MEFs). The results show us an increasing of IC50 from 0.110 mg/mL for Fe3O4 NPs to 0.405 mg/mL for Fe3O4-Carborane NPs. The obtained data confirm the biocompatibility and stability of synthesized NPs and the potential to use them in BNCT.

NiFe nanocrystalline films were formed onto Au film via pulsed electrolyte deposition with variable time of relaxation between the sequential pulses. Analysis of anomalous non-liner changes in the NiFe film structure showed the implementation of three mechanisms, resulting in "layer-by-layer", "layer-plus-island", or "island" growth. The change of the interpulse relaxation time provides the possibility to realize all three different mechanisms. The grown NiFe films may have different morphology. The ultrathin NiFe films have nanosized grains and exhibit high uniformity of structure, the films may be also combined of less that 10 nm nanoscale grains and their conglomerates, typically, about 50 nm in size, and, additionally, the film structure, consisting of isolated magnetic islands can be realized. The phenomenological explanation of the different mechanisms was obtained using atomic-force-microscopy (AFM) approach. It has been demonstrated that the growth mechanism can be controlled by nanocrystallites conglomeration, which is accelerated with increasing the relaxation time. The origin of the conglomeration process is mainly associated with high surface energy of nanosized grains.

BaFe12−xGaxO19 hexaferrites were synthesized via the usual ceramic technology; with an increase in x, the unit cell and magnetic parameters monotonically decrease.