INTRODUCTION: Magnetic nanoparticles (NPs) represent a tool for use in magnetic resonance imaging (MRI)-guided thermoablation of tumors using an external high-frequency (HF) magnetic field. To avoid local overheating, perovskite NPs with a lower Curie temperature (T c) were proposed for use in thermotherapy. However, deposited power decreases when approaching the Curie temperature and consequently may not be sufficient for effective ablation. The goal of the study was to test this hypothesis. METHODS: Perovskite NPs (T c =66°C-74°C) were characterized and tested both in vitro and in vivo. In vitro, the cells suspended with NPs were exposed to a HF magnetic field together with control samples. In vivo, a NP suspension was injected into a induced tumor in rats. Distribution was checked by MRI and the rats were exposed to a HF field together with control animals. Apoptosis in the tissue was evaluated. RESULTS AND DISCUSSION: In vitro, the high concentration of suspended NPs caused an increase of the temperature in the cell sample, leading to cell death. In vivo, MRI confirmed distribution of the NPs in the tumor. The temperature in the tumor with injected NPs did not increase substantially in comparison with animals without particles during HF exposure. We proved that the deposited power from the NPs is too small and that thermoregulation of the animal is sufficient to conduct the heat away. Histology did not detect substantially higher apoptosis in NP-treated animals after ablation. CONCLUSION: Magnetic particles with low T c can be tracked in vivo by MRI and heated by a HF field. The particles are capable of inducing cell apoptosis in suspensions in vitro at high concentrations only. However, their effect in the case of extracellular deposition in vivo is questionable due to low deposited power and active thermoregulation of the tissue.
- MeSH
- ablace přístrojové vybavení metody MeSH
- indukovaná hypertermie metody MeSH
- kontrastní látky * chemie farmakokinetika MeSH
- magnetická rezonanční tomografie přístrojové vybavení metody MeSH
- magnety MeSH
- nádorové buněčné linie MeSH
- nanočástice * chemie MeSH
- oxid křemičitý chemie MeSH
- oxidy chemie MeSH
- potkani Wistar MeSH
- sloučeniny vápníku chemie MeSH
- suspenze MeSH
- teplota MeSH
- titan chemie MeSH
- xenogenní modely - testy antitumorózní aktivity MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Silicate paints containing photocatalytically active TiO2 and ZnO nanoparticles were formulated. The photocatalytic efficiency of coatings was evaluated as a change in absorbance of Orange II solutions. The agar plate method was used for evaluation of antimicrobial properties of coatings. The effectiveness of the coatings was demonstrated using Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus bacteria and Aspergillus niger and Penicillium chrysogenum fungi. A slightly better photocatalytic effect was found in the coatings containing TiO2 nanoparticles than in those with ZnO. The antimicrobial activity of coatings containing nano-TiO2 was negligible. The silicate coatings containing 7.5 vol.% of ZnO nanoparticles showed an excellent antimicrobial activity against all tested bacteria and fungi Aspergillus niger; they partly inhibited also the Penicillium chrysogenum growth. Statistically significant differences between the control coatings and those with ZnO nanoparticles were found using the Rank-sum test.
- MeSH
- antiinfekční látky toxicita MeSH
- Bacteria růst a vývoj účinky léků MeSH
- financování organizované MeSH
- houby růst a vývoj účinky léků MeSH
- klinické laboratorní techniky trendy využití MeSH
- nanočástice mikrobiologie toxicita využití MeSH
- nátěrové hmoty toxicita využití MeSH
- oxid zinečnatý chemie toxicita MeSH
- oxidy chemie toxicita MeSH
- protézy a implantáty mikrobiologie využití MeSH
- silikáty chemie toxicita MeSH
- statistika jako téma MeSH
- titan chemie toxicita MeSH
- ultrafialové záření MeSH
- zdravotnické prostředky mikrobiologie MeSH
