ABSTRACT
Magnetic hyperthermia (MHT) is a therapy that uses the heat generated by a magnetic material for cancer treatment. Magnetite nanoparticles are the most used materials in MHT. However, magnetite has a high Curie temperature (Tc~580 °C), and its use may generate local superheating. To overcome this problem, strontium-doped lanthanum manganite could replace magnetite because it shows a Tc near the ideal range (42-45 °C). In this study, we developed a smart composite formed by an F18 bioactive glass matrix with different amounts of Lanthanum-Strontium Manganite (LSM) powder (5, 10, 20, and 30 wt.% LSM). The effect of LSM addition was analyzed in terms of sinterability, magnetic properties, heating ability under a magnetic field, and in vitro bioactivity. The saturation magnetization (Ms) and remanent magnetization (Mr) increased by the LSM content, the confinement of LSM particles within the bioactive glass matrix also caused an increase in Tc. Calorimetry evaluation revealed a temperature increase from 5 °C (composition LSM5) to 15 °C (LSM30). The specific absorption rates were also calculated. Bioactivity measurements demonstrated HCA formation on the surface of all the composites in up to 15 days. The best material reached 40 °C, demonstrating the proof of concept sought in this research. Therefore, these composites have great potential for bone cancer therapy and should be further explored.
ABSTRACT
This study evaluated the gene expression profile of the human adipose-derived stem cells (hASCs) grown on the Biosilicate® /F18 glass (BioS-2P/F18) scaffolds. hASCs were cultured using the osteogenic medium (control), the scaffolds, and their ionic extract. We observed that ALP activity was higher in hASCs grown on the BioS-2P/F18 scaffolds than in hASCs cultured with the ionic extract or the osteogenic medium on day 14. Moreover, the dissolution product group and the control exhibited deposited calcium, which peaked on day 21. Gene expression profiles of cell cultured using the BioS-2P/F18 scaffolds and their extract were evaluated in vitro using the RT2 Profiler polymerase chain reaction (PCR) microarray on day 21. Mineralizing tissue-associated proteins, differentiation factors, and extracellular matrix enzyme expressions were measured using quantitative PCR. The gene expression of different proteins involved in osteoblast differentiation was significantly up-regulated in hASCs grown on the scaffolds, especially BMP1, BMP2, SPP1, BMPR1B, ITGA1, ITGA2, ITGB1, SMAD1, and SMAD2, showing that both the composition and topographic features of the biomaterial could stimulate osteogenesis. This study demonstrated that gene expression of hASCs grown on the scaffold surface showed significantly increased gene expression related to hASCs cultured with the ionic extract or the osteogenic medium, evidencing that the BioS-2P/F18 scaffolds have a substantial effect on cellular behavior of hASCs.
