br As can be seen from
As can be seen from Fig. 5(b) and (c), the calcium and phosphorous ion concentration for control sample (only SBF, without any immersed sample) presented no significant changes. It can be concluded that no precipitation of calcium or phosphorous ions has been happened during immersion experiments. There was a significant increase in the pH value of the SBF solution by increasing iron content in the structure of the immersed samples (Fig. 4(d)). The releasing of Fe ions in SBF solution generated OH– [25,26], which could greatly increase the pH value of the SBF and ex-ceed the physiological pH range. The high release of Fe and significant
changes of the pH value could strongly affect viability, growth, and cohesion of the SCH 58261 on the surface of implants . Therefore, mag-netite could not provide a desirable environment for cells.
After bioactivity properties, next we study the biocompatibility of the synthesized HT materials.
3.4. In vitro cell proliferation
A key requirement of materials for tissue engineering application is their biocompatibility as well as their ability to support cellular growth and proliferation. After removal of cancer tumors from bone tissue, the defect and cavity should be filled with a material that should first prevent the growth of cancer cells and then support tissue regeneration. Magnetite has been extensively studied for engineering constructs that can induce hyperthermia in response to a magnetic field [28–31]. However, its biocompatibility has not been impressive and has limited its widespread use. Here, we compared the biocompatibility of mag-netite powder with the prepared HT and 0.2Fe-HT powders.
Human mesenchymal stem cells (hMSCs) were seeded in 48-well plates (15,000 cells/well) containing 50 mg of powder each (the best amount of powder to cover the bottom of wells perfectly). The viability and metabolic activity of the cells were assessed using Live/Dead and PrestoBlue assays, respectively. The Live/Dead assay results are de-picted in Fig. 6 where the live and dead cells are shown in green and red color, respectively. The results show the growth of cells over the 7 days of culture period in HT and 0.2Fe-HT as well as the control well plate. The cells cultured in wells containing 50 mg of magnetite showed low viability. Another interesting point in Fig. 5 was the adhesion of cells to the HT and 0.2Fe-HT powder. As can be seen, magnetite does not support cellular adhesion on its surface and could have a potentially negative impact on the morphology and adhesion of human
Fig. 6. Live and dead staining of hMSCs incubated with PBS (control) and seeded on magnetite, HT and 0.2Fe-HT powders in different days. Live and dead cells are presented in green and red color, respectively. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Fig. 7. Live and dead staining of tumor Saos-2 cells incubated with PBS (control) and seeded on magnetite and 0.2Fe-HT powders in different days. All samples were exposed to AMF with 45.2 G field strength. Live and dead cells are presented in green and red color, respectively. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Fig. 8. (a) Metabolic activity of hMSCs-seeded on magnetite, HT and 0.2Fe-HT powder at different times post-seeding. (b) Viability of hMSCs seeded on HT, 0.2Fe-HT and magnetite samples reported by dividing the live cell count by the total cell count. (c) Schematic shows the illustration of hMSCs culturing on the samples to evaluate their tissue engineering abilities. (d) Metabolic activity of Saos-2 cells-seeded on magnetite and 0.2Fe-HT powders as well as control sample when exposed to AMF at different times post-seeding. (e) Viability of Saos-2 cells seeded on HT, 0.2Fe-HT and magnetite samples when exposed to an alternating magnetic field, reported by dividing the live cell count by the total cell count. (f) Schematic figure shows how Saos-2 cells culture on the samples to evaluate their hyperthermia abilities. RFU stands for relative fluorescence units. (*p < 0.05, **p < 0.01, ***p < 0.001, ns stands for not significant).