We have produced an innovative, theranostic material based on FePt/SiO2/Au hybrid nanoparticles (NPs) for both, photo-thermal therapy and magnetic resonance imaging (MRI). Furthermore, a new synthesis approach, i.e., Au double seeding, for the reparation of Au nanoshells around the FePt/SiO2 cores, is roposed. The photothermal and the MRI response were first demonstrated on an aqueous suspension of hybrid FePt/SiO2/Au NPs. The cytotoxicity together with the internalization mechanism and the intracellular fate of the hybrid NPs were evaluated in vitro on a normal (NPU) and a half-differentiated cancerous cell line (RT4). The control samples as well as the normal cell line ncubated with the NPs showed no significant temperature increase during the in vitro photo-thermal treatment (ΔT ( 0.8 °C) and thus the cell viability remained high (∼90%). In contrast, due to the high NP uptake by the cancerous RT4 cell line, significant heating of the sample was observed (ΔT = 4 °C) and, consequently, after laser irradiation the cell viability dropped significantly to ∼60%. These results further confirm that the hybrid FePt/SiO2/Au NPs developed in the scope of this work were not only efficient but also highly selective photo-thermal agents. Furthermore, the improvement in the contrast and the easier distinction between the healthy and the cancerous tissues were clearly demonstrated with in vitroMRI experiments, proving that hybrid NPs have an excellent potential to be used as contrast agents.
COBISS.SI-ID: 30987559
The first one-step synthesis of dumbbell-like gold–iron oxide nanoparticles has been reported here. Surface functionalization with a biocompatible chitosan matrix allowed us to obtain a novel targetable diagnostic and therapeutic tool. Such system enables both, novel and non-invasive photoacoustic imaging (PAI) and photothermal therapy (PTT).
COBISS.SI-ID: 29014055
In this investigation, we have produced an innovative material based on FePt/SiO2/Au hybrid nanoparticles that exhibit a combination of photothermal and magnetic properties as a basis for a local hypothermia treatment. The magnetic cores of FePt exhibit the superparamagnetic properties necessary for biomedical purposes, while the gold nanoshells absorb light in the near-infrared range, because of their semicontinuous nature and the nanoparticle clustering, as predicted by our modeling. The as-prepared hybrid FePt/SiO2/Au nanoparticles were irradiated with a low-energy laser (λ = 808 nm) in a water suspension, which resulted in a photothermal effect and a temperature increase of 10 °C during the 10 min of irradiation. Furthermore, the results of experiments performed on a suspension of hybrid nanoparticles in a flow of water confirmed that they can be magnetically manipulated and retained at a targeted location under realistic dynamic conditions. This dual magnetic and optical effect makes the FePt/SiO2/Au hybrid nanoparticles excellent candidates for photothermal cancer treatments, with the added bonus of being able to magnetically extract the particles after their use.
COBISS.SI-ID: 28708903
The value of the magnetization has a strong influence on the performance of nanoparticles that act as the contrast agent material for MRI. In this article, we describe processing routes for the synthesis of FePt nanoparticles of different sizes, which, as a result, exhibit different magnetization values. “Single-core” FePt nanoparticles of different sizes (3–15 nm) were prepared via one-step or two-step synthesis, with the latter exhibiting twice the magnetization (m(1.5T) = 14.5 emu/g) of the nanoparticles formed via the one-step synthesis (m(1.5T) ( 8 emu/g). Furthermore, we propose the synthesis of “multi-core” FePt nanoparticles by changing the ratio between the two surfactants (oleylamine and oleic acid). The step from smaller “single-core” FePt nanoparticles towards the larger, “multi-core” FePt nanoparticles ()20 nm) leads to an increase in the magnetization m(1.5T) from 8 to 19.5 emu/g, without exceeding the superparamagnetic limit. Stable water suspensions were prepared using two different approaches: (a) functionalization with a biocompatible, zwitterionic, catechol ligand, which was used on the FePt nanoparticles for the first time, and (b) coating with SiO2 shells of various thicknesses. These FePt-based nanostructures, the catechol- and SiO2-coated “single-core” and “multi-core” FePt nanoparticles, were investigated in terms of the relaxation rates. The higher r2 values obtained for the “multi-core” FePt nanoparticles compared to that for the “single-core” ones indicate the superiority of the “multi-core” FePt nanoparticles as T2 contrast agents. Furthermore, it was shown that the SiO2 coating reduces the r1 and r2 relaxation values for both the “single-core” and “multi-core” FePt nanoparticles. The high r2/r1 ratios obtained in our study put FePt nanoparticles near the top of the list of candidate materials for use in MRI.
COBISS.SI-ID: 29092647
Nanomaterials conjugated or complexed with biological moieties such as antibodies, polymers or peptides appear to be suitable not only for drug delivery but also for specific cancer treatment. Here, biocompatible iron oxide magnetic nanoparticles (MNPs) with or without a silica shell coupled with lentiviral vectors (LVs) are proposed as a combined therapeutic approach to specifically target gene expression in a cancer mouse model. MNPs and LVs strictly interacted and transduced cells in vitro as well as in vivo, with no toxicity or inflammatory responses. By injecting LV-MNPs complexes intravenously, green fluorescent protein (GFP) resulted in a sustained long-term expression. Furthermore, by applying a magnetic field on the abdomen of intravenous injected mice, GFP positive cells increased in livers and spleens. In liver, LV-MNPs were able to target both hepatocytes and non-parenchymal cells, while in a mouse model with a grafted tumor, intra-tumor LV-MNPs injection and magnetic plaque application next to the tumor demonstrated the efficient uptake of LV-MNPs complexes with high number of transduced cells and iron accumulation in the tumor site. More important, LV-MNPs with the application of the magnetic plaque spread in all the tumor parenchyma and dissemination through the body was prevented confirming the efficient uptake of LV-MNPs complexes in the tumor. Thus, these LV-MNPs complexes could be used as multifunctional and efficient tools to selectively induce transgene expression in solid tumor for therapeutic purposes.
COBISS.SI-ID: 30651687