Synthesis and Characterization of Tb‐Doped Nanoferrites

Abstract

Tb3+‐substituted superparamagnetic iron‐oxide‐based nanoparticles (NPs) that can be promising for possible multimodal drug carrier and radiotherapy are presented. These NPs were obtained using a reverse micelle template method with controlled micelle size. The atomic ratio of Tb/Fe ions was found to be very close to that expected from the stoichiometry of the reagents used. Aqueous suspensions of Tb‐doped nanoferrites are emissive with emission peaks characteristic for the Tb3+ dopant. Time‐resolved fluorescence decay data revealed two populations occupying inequivalent matrix sites. Above 80 K the Tb‐doped nanoferrites were superparamagnetic, which is a prerequisite for their use as carriers in magnetic‐field‐driven targeted therapies. The incorporation of up to 15 at.% of Tb3+ in their core resulted in a decrease of magnetization. Nevertheless, this magnetization appears to be sufficient for their use as carriers in an external magnetic field, and, of equal importance, stable isotope 159Tb3+ could be replaced by radioactive 161Tb3+, yielding multimodal NPs, suitable for conjugated therapies such as radiotherapy and magnetothermal therapy, as well as targeted drug delivery.

Easy Synthesis and Characterization of Holmium-Doped SPIONs

“…85–90 pm radius, and there is a large ionic radii mismatch for Ho 3+ (104 pm) as compared to Fe 3+ (78.5 pm) ions that are to be replaced in this lattice. However, the literature data [ 35 ] and our results for SPIONs modified with Tb (106 pm) [ 33 ] indicate that such replacement is possible, at least for terbium cations, requiring local lattice distortion and favouring incorporation of these ions into octahedral and surface sites. On the other hand, most ferrites are ferrimagnetic, i.e., part of magnetic moments of the constituent ions are antiparallel, partially compensating for the overall magnetic moment of SPIONs.…”

“…Substitution with ions with an ionic radius similar to Fe 3+ (0.785 Å) [ 31 ] does not affect the magnetic behaviour of the doped SPIONs significantly, while the incorporation of lanthanide ions like Ho 3+ (1.01 Å) [ 32 ] with a large radius, ca. 30% larger than Fe 3+ , may lead to core anisotropy, crystallographic lattice alterations and a decrease in the magnetic properties due to the Fe(III) and Ho(III) ionic radii mismatch [ 33 , 34 ].…”

Trastuzumab Conjugated Superparamagnetic Iron Oxide Nanoparticles Labeled with 225Ac as a Perspective Tool for Combined α-Radioimmunotherapy and Magnetic Hyperthermia of HER2-Positive Breast Cancer

“…In addition to cyclic and linear ligands like DOTA, HEHA or DTPA, they were various types of nanoparticles like gadolinium vanadate nanocrystals [16], polymersomes [17], indium and lanthanum phosphates [18,19]. In our work as a carrier for 225 Ac, we proposed to use Superparamagnetic Iron Oxide-based Nanoparticles (SPIONs) where actinium similarly to lanthanides should be incorporated into their magnetic core [20]. SPIONs have attracted wide attention due to their unique properties originating from intrinsic magnetic properties (due to ferromagnetic iron), high surface area-to-volume ratio, and the ability to chemically modify their core composition and their surfaces.…”

Sensitization Mechanism of Alumina Aerogels: Introducing Gd3+ as a Sensitizing Ion to Enhance the Luminescence Intensity of Tb3+

“…Combined with SEM images (see below), it could be observed that the incorporation of Tb 3+ /Gd 3+ had a great influence on the microstructure of Al 2 O 3 aerogel matrix. In addition, the doping of the sensitizing ion Gd 3+ did not change the crystal structure of Al 2 O 3 : Tb 3+ , suggesting that the ionic radius of Tb 3+ and Gd 3+ were similar, [24,25] and they occupied the crystal lattice site of Al 2 O 3 at the same time. These results indicated that the rare earth metal ions and the Al 2 O 3 aerogel matrix have strong binding force with Al 2 O 3 aerogel matrix, and the as‐prepared phosphor material had good physical and chemical stability.…”