Mechanical and Biological Properties of Magnesium- and Silicon-Substituted Hydroxyapatite Scaffolds

Round 1

Reviewer 1 Report

The authors designed ion-substituted hydroxyapatite scaffols, in particular, they doped with magnesium and silicon ions, to improve  the bone regeneration process.  Experiments have been done carefully, with samples in triplicates to ensure reproducibility and attempt to verify statistical significance. This study confirms that  HA-Si and HA-MgSi scaffolds induce osteogenic differentiation of bone marrow mesenchymal stem cells. I recommend the publication of this manuscript in the present form. 

Author Response

thank you for recommending  this manuscript for publication

Reviewer 2 Report

This study demonstrates the mechanical and biological properties of magnesium and silicon substituted hydroxyapatite scaffolds. Overall, the manuscript is well written, and the evaluations are well conducted. However, some revisions may be required.

1. Figure 5. It seems that the addition of  magnesium and silicon may increased the brittleness of the scaffolds. I suggest the authors should provide images of the compression test.
2. The authors should provide with  the results of the significance test in some of the graphs.
3. Figure 9. The quality of the fluorescence images should be enhanced.
4. Figure 9. It would be helpful to the readers if quantitative results of the fluorescence images were provided.

Author Response

1. Figure 5. It seems that the addition of  magnesium and silicon may increased the brittleness of the scaffolds. I suggest the authors should provide images of the compression test.

Thank you for the comment. We have inserted the compression test image in inset of figure 5

2. The authors should provide with  the results of the significance test in some of the graphs.

Thank you for the comment. We have inserted results of the significance test

3. Figure 9. The quality of the fluorescence images should be enhanced.

Thank you for the comment. The quality of the fluorescence image has enhanced

4. Figure 9. It would be helpful to the readers if quantitative results of the fluorescence images were provided.

Thank you for the comment. At the moment we are not able to provide quantitative result. If you want, we can delete figure 9 considering that the microscopy images do not add significant information.

Reviewer 3 Report

The manuscript submitted by Padmanabhanand co-workers is about the Mechanical and biological properties of HA-MgSi scaffolds.

Authors tested the nanosheets with different fungi strains and proved their antifungal activity with several techniques including microscopy characterizations. Moreover, compared the effectivity of the nanosheets with other nanomaterials showing that MoSe2/Chitosan works better as antifungal.

This work is interesting in the field and the manuscript is well structured, however, there are some items that need to be addressed before this work is suitable for publication:

• Scale bars in Figure 1 should be bigger.
• Authors should include the TEM image of HA-MgSi in Figure 1.
• In Figure 2, what is the figure caption of Figure 2c?
• Scale bars in Figure 4 should be bigger and clear.
• What is PU in line 246?
• Authors should keep the same sequence of colors for samples from Figure 2 in the rest of figures.
• Authors should include statistical analysis to Figure 7 and Figure 8.
• The format of Figure 6, Figures 8, Figure 10 and Figure 11 should be as Figure 7.
• Authors should include the profile release of Ca, P, Mg and Si ions in each sample.
• What is the influence of ions release in the mechanical and biological results?

Author Response

1. Scale bars in Figure 1 should be bigger.

Thank you for the comment. Scale bar changed and unit is mentioned in the figure caption

2. Authors should include the TEM image of HA-MgSi in Figure 1.

Thank you for the comment. We haven’t synthesized HA-MgSi powder. We used HA-Mg and Ha-Si powder to make the HA-MgSi scaffold

3. In Figure 2, what is the figure caption of Figure 2c?

Thank you for the comment. The reviewer mentioned about figure 3. We corrected in the manuscript

4. Scale bars in Figure 4 should be bigger and clear.

Thank you for the comment. Scale bar modified

5. What is PU in line 246?

Thank you for the comment. PU is polyurethane. We introduced abbreviation in experiment section

6. Authors should keep the same sequence of colors for samples from Figure 2 in the rest of figures.

Thank you for the comment. We have changed color of the graphic figures

7. Authors should include statistical analysis to Figure 7 and Figure 8.

Thank you for the comment. Included statistical analysis

8. The format of Figure 6, Figures 8, Figure 10 and Figure 11 should be as Figure 7.

Thank you for the comment. corrected

9. Authors should include the profile release of Ca, P, Mg and Si ions in each sample.

What is the influence of ions release in the mechanical and biological results?

Thank you for the comment. In this study we are not conducted the ion release study. In future study we will do

Reviewer 4 Report

1. Line 107 - How many tests were done? According which standard?
2. Figure 5 – mean values?
3. Figure 6 – In the case of HA-MgSi the standard deviation is high. Did the authors consider further testing?
4. Line 103 – How was r0 obtained?
5. Line 192 – Why not use, for example, Anova test?
6. For 28 days the standard deviation is high, so the conclusions may be questionable.
7. Figure 7 – With such a high standard deviation for some experiments, is just 3 tests enough? I do not think.
8. Figure 9 – No perceptible. Perhaps the authors can identify in the figure what they want to show.
9. Why do some references appear without an identification number?
10. Why choose these mechanical tests? Based on what?
11. With poor discussion with open literature, all the conclusions can be questionable.

Author Response

1. Line 107 - How many tests were done? According which standard?

Thank you for the comment. In the next line we have mentioned about the number of samples tested for each batch. “Six samples for each scaffolds batch were tested to obtain the stress at failure (σ_max) and the results were expressed as average value ± sd.”

2. Figure 5 – mean values?

Thank you for the comment. Mean values is represented and mentioned in the text.

3. Figure 6 – In the case of HA-MgSi the standard deviation is high. Did the authors consider further testing?

Thank you for the comment. Six samples were tested and we noticed this large scattering of weight loss value at more than 2 week of degradation study.

4. Line 103 – How was r0 obtained?

Thank you for the comment. We used the theoretical density of hydroxyapatite5. 5. Line 192 – Why not use, for example, Anova test?

Thank you for the comment.  We used Student’s t test

6. For 28 days the standard deviation is high, so the conclusions may be questionable.

Thank you for the comment. Its true

7. Figure 7 – With such a high standard deviation for some experiments, is just 3 tests enough? I do not think.

Thank you for the comment. We have tested six samples for each batch

8. Figure 9 – No perceptible. Perhaps the authors can identify in the figure what they want to show.

Thank you for the comment. If you want, we can delete figure 9 considering that the microscopy images do not add significant information.

9. Why do some references appear without an identification number?

Thank you for the comment.  It’s a book chapter

10. Why choose these mechanical tests? Based on what?

Thank you for the comment. We have cited the reference

11. With poor discussion with open literature, all the conclusions can be questionable.

Thank you for the comment. Discussion improved with citing relevant references

Round 2

Reviewer 3 Report

There are typos in scale bars of Figure 4.

The scale bars in Figure 9 are not visible.

Author Response

There are typos in scale bars of Figure 4.

Thank you for the comment. Rectified

The scale bars in Figure 9 are not visible.

thank you for the comment. we introduced scale bar

Reviewer 4 Report

Authors should try to explain why for 28 days the standard deviation is high.

Author Response

Authors should try to explain why for 28 days the standard deviation is high.

Thank you for your comment. we have added a sentence in the manuscript

"At 28 days, the reported weight loss and compression strength showed larger scattering from the mean value, which may be due to rapid loss of ions from the ceramic strut at longer incubation time and it varied from sample to sample."