Biosynthesis of Zinc Oxide Nanoparticles Using Capparis spinosa L. Fruit Extract: Characterization, Biocompatibility, and Antioxidant Activity

Round 1

Reviewer 1 Report

Thanks for trusting me. The authors had a study on the cytotoxicity, antioxidant effect, and hemocompatibility of zinc oxide nanoparticles (ZnONPs) produced utilizing Capparis spinosa L. (C.spinosa L.) fruit extract as a powerful reducing agent. The subject is not novel in general. However, it include many valauble investigations for these nanoparticles. The scientific content level is good. The investigation methods are complete. The writing level is good generally. However, I had some major and minor concerns.

Majors:

The general line of the abstract is not so good. The authors should mention the importance of their study using potent backgrounds. Besides, some more recent and relevan studies (refernces) are needed to include.

Please remove the sentence"To our knowledge, the green synthesis of ZnO NPs using C.spinosa L. fruit extract and their antioxidant, and cytotoxicity properties are not well documented' from the introduction and add your main aims instead.

How the authors determined the mean size of nanoparticles from SEM image? It should be added.

Why the mean size from DLS, SEM  and Uv-visible methods are different? The reasons should be discuss.

The SEM image dose not show nanoparticles. How you claim the aggrigates are nanoparticles? I think the image can be changed.

What were the statistical methods for cytotaxicity and hemolysis methods?

Minors:

Please check for typo or grammatical errors.

Please add the numbers for main functional groups for FTIR.

Some minor typo errors.

Author Response

Dear Editor, and reviewers

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Biosynthesis of Zinc Oxide Nanoparticles using Capparis spinosa L. fruit extract: Their Characterizations, biocompatibility, and antioxidant activities”. Those comments are all really valuable and helpful in revising and improving our manuscript, as well as providing significant direction for our research. We carefully considered the comments and made changes that we hope will be approved. The revised sections of the document are highlighted in red. The followings are the main corrections in the manuscript and responses to the reviewers’ comments.

Reviewer #1:

 Comments and Suggestions for Authors

Thanks for trusting me. The authors had a study on the cytotoxicity, antioxidant effect, and hemocompatibility of zinc oxide nanoparticles (ZnONPs) produced utilizing Capparis spinosa L. (C.spinosa L.) fruit extract as a powerful reducing agent. The subject is not novel in general. However, it include many valuable investigations for these nanoparticles. The scientific content level is good. The investigation methods are complete. The writing level is good generally. However, I had some major and minor concerns.

Majors:

1. The general line of the abstract is not so good. The authors should mention the importance of their study using potent backgrounds. Besides, some more recent and relevan studies (references) are needed to include.

Author’s response:  Thank you for your comments: We have improved the general line of the abstract. Additionally, we emphasized the significance of our work by providing some additional recent and relevant findings in the introduction and discussion sections. (Please see the revised manuscript).

2. Please remove the sentence"To our knowledge, the green synthesis of ZnO NPs using C.spinosa L. fruit extract and their antioxidant, and cytotoxicity properties are not well documented' from the introduction and add your main aims instead.

Author’s response: Thank you for your valuable comments: The sentence has been removed and replaced with our main aims. (Please see the revised manuscript).

3. How the authors determined the mean size of nanoparticles from SEM image? It should be added.

Author’s response: Thank you for your valuable comments: the mean size of obtained nanoparticles was through FESEM  approximately calculated by measuring a few hundred of the particles using Image J software.

(Please see the revised manuscript).

4. Why the mean size from DLS, SEM  and Uv-visible methods are different? The reasons should be discuss.

Author’s response: Thank you for your comments: The diameter of the particles as determined by DLS is significantly larger than that of the SEM size analysis if the suspension is aggregated.

 DLS average sizes are larger than those determined from SEM images, which is most probably because ZnONPs observed in SEM were only seen on the surface of the agglomerates. In contrast, DLS measures the particles’ three-dimensional, which might include a biomolecular coating. Such discrepancy between SEM and DLS average size has been reported before and is related to the specifics of the method used.

The UV-vis absorption spectrum exhibits an absorption band at 374 nm that can be attributed to the intrinsic band-gap absorption of ZnO nanoparticles because of electron transfers from the valence band to the conduction band (O2p Zn3d). (Please see the revised manuscript)

5. The SEM image does not show nanoparticles. How you claim the aggrigates are nanoparticles? I think the image can be changed.

Author’s response: Thank you for your comments: Most ZnONPs were aggregated, according to the SEM image. the average particle size distribution of green ZnO NPs mainly around 37.493±2.205 nm According to our calculations using the "image J"  software. (Please see the revised manuscript)

Author Response File: Author Response.pdf

Reviewer 2 Report

The presented manuscript includes the study of biosynthesis of zinc oxide nanoparticles using Capparis spinosa L. fruit extract: their characterizations, biocompatibility, and antioxidant activities. 

The results of the work are presented on a good level but some questions and weak points should be mentioned. 

1. Please, do not use more than 3 references in one place (like [1-4], [5-10], [13-17], etc.). Either you should describe the differences.

2. Please make subsection “2.1 Materials and reagents”. There please mention all used reagents in your study. Mention their provider, composition, and purity.

3. Please show the exact planes in the XRD diffractogram (fig. 3), and mention the defined phases. Change “peak position (20)” to “2theta (degrees)”

4. Fig.4. Please highlight the waves mentioned in the text. It is a good practice to treat images.

5. Please, delete Fig.6. It gives almost nothing and makes your paper looks worst (this is the usual practice of some authors in low-impact journals, looks as worst as the stretching of images). Instead of EDS spectra write one sentence in the text if there is really something to describe or just leave Table 1 (same, if it is really needed). 

6. Particle size distribution and BET analysis are important for such kinds of experiments.

7. The novelty of the paper is not clear. What are the benefits of your ZnO NPs compared with those obtained by other approaches?

8. All obtained results have to be compared with published analogs.

Author Response

Dear Editor and Reviewers,

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Biosynthesis of Zinc Oxide Nanoparticles using Capparis spinosa L. fruit extract: Their Characterizations, biocompatibility, and antioxidant activities”. Those comments are all really valuable and helpful in revising and improving our manuscript, as well as providing significant direction for our research. We carefully considered the comments and made changes that we hope will be approved. The revised sections of the document are highlighted in red. The followings are the main corrections in the manuscript and responses to the reviewers’ comments.

Reviewer #2:

 The presented manuscript includes the study of biosynthesis of zinc oxide nanoparticles using Capparis spinosa L. fruit extract: their characterizations, biocompatibility, and antioxidant activities.

The results of the work are presented on a good level but some questions and weak points should be mentioned.

1. Please, do not use more than 3 references in one place (like [1-4], [5-10], [13-17], etc.). Either you should describe the differences.

Author’s response: Thank you for your comments: We have arranged and described each reference in the text. (Please see the revised manuscript).

2. Please make subsection “2.1 Materials and reagents”. There please mention all used reagents in your study. Mention their provider, composition, and purity.

Author’s response: Thank you for your comments: “2.1 Materials and reagents” has been added to the material and methods section (Please see the revised manuscript)

3. Please show the exact planes in the XRD diffractogram (fig. 3), and mention the defined phases. Change “peak position (20)” to “2theta (degrees)”.

Author’s response: Thank you for your valuable comments: The exact planes have been added to the XRD diffractogram (Figure 3). and "peak position (20)" has been changed to "2theta (degrees)". (Please see the revised manuscript).

4. 4. Please highlight the waves mentioned in the text. It is a good practice to treat images.

Author’s response: Thank you for your valuable comments: The waves that are mentioned in the text have been identified in the updated Figure 4. (Please see the revised manuscript).

5. Please, delete Fig.6. It gives almost nothing and makes your paper looks worst (this is the usual practice of some authors in low-impact journals, looks as worst as the stretching of images). Instead of EDS spectra write one sentence in the text if there is really something to describe or just leave Table 1 (same, if it is really needed).

Author’s response: Thank you for your comments: Thank you for your valuable comments: We have removed Figure 6. and also table 1. (Please see the revised manuscript).

6. Particle size distribution and BET analysis are important for such kinds of experiments.

Author’s response: Thank you for your comments: While the suggested idea of considering adding BET analysis as a test for such kinds of experiments, seems interesting in studies dealing with green synthesis, However, the present study is mainly focused on the characterization and in vitro Evaluation of cytotoxicity, Hemolysis, and Antioxidant Properties. Therefore, we believe that adding BET analysis of our green ZnO NPs remains to be done in future papers.

7. The novelty of the paper is not clear. What are the benefits of your ZnO NPs compared with those obtained by other approaches?

Author’s response: Thank you for your comments, to our knowledge, the synthesis of ZnO NPs using C.spinosa L. and their cytotoxicity, Hemolysis, and Antioxidant Properties are not well documented.  

This is the first study that investigates the effect of employing C.spinosa L fruit extract as an effective reducing agent for the green chemistry synthesis of ZnO NPs. This part could reflect the novelty of our study.

8. All obtained results have to be compared with published analogs.

Author’s response: Thank you for your comments: The results and discussion sections have been updated by Comparing the obtained results to published analogs. (Please see the revised manuscript).

Round 2

Reviewer 1 Report

It can be accepted. Thanks

Author Response

Dear Editor and Reviewers,

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Biosynthesis of Zinc Oxide Nanoparticles using Capparis spinosa L. fruit extract: Their Characterizations, biocompatibility, and antioxidant activities”. Those comments are all really valuable and helpful in revising and improving our manuscript, as well as providing significant direction for our research. We carefully considered the comments and made changes that we hope will be approved. The revised sections of the document are highlighted in red. The followings are the main corrections in the manuscript and responses to the reviewers’ comments.

Reviewer #1:

 Comments and Suggestions for Authors

Thanks for trusting me. The authors had a study on the cytotoxicity, antioxidant effect, and hemocompatibility of zinc oxide nanoparticles (ZnONPs) produced utilizing Capparis spinosa L. (C.spinosa L.) fruit extract as a powerful reducing agent. The subject is not novel in general. However, it include many valuable investigations for these nanoparticles. The scientific content level is good. The investigation methods are complete. The writing level is good generally. However, I had some major and minor concerns.

Majors:

1. The general line of the abstract is not so good. The authors should mention the importance of their study using potent backgrounds. Besides, some more recent and relevan studies (references) are needed to include.

Author’s response:  Thank you for your comments: We have improved the general line of the abstract. Additionally, we emphasized the significance of our work by providing some additional recent and relevant findings in the introduction and discussion sections. (Please see the revised manuscript).

2. Please remove the sentence"To our knowledge, the green synthesis of ZnO NPs using C.spinosa L. fruit extract and their antioxidant, and cytotoxicity properties are not well documented' from the introduction and add your main aims instead.

Author’s response: Thank you for your valuable comments: The sentence has been removed and replaced with our main aims. (Please see the revised manuscript).

3. How the authors determined the mean size of nanoparticles from SEM image? It should be added.

Author’s response: Thank you for your valuable comments: the mean size of obtained nanoparticles was through FESEM  approximately calculated by measuring a few hundred of the particles using Image J software.

(Please see the revised manuscript).

4. Why the mean size from DLS, SEM  and Uv-visible methods are different? The reasons should be discuss.

Author’s response: Thank you for your comments: The diameter of the particles as determined by DLS is significantly larger than that of the SEM size analysis if the suspension is aggregated.

 DLS average sizes are larger than those determined from SEM images, which is most probably because ZnONPs observed in SEM were only seen on the surface of the agglomerates. In contrast, DLS measures the particles’ three-dimensional, which might include a biomolecular coating. Such discrepancy between SEM and DLS average size has been reported before and is related to the specifics of the method used.

The UV-vis absorption spectrum exhibits an absorption band at 374 nm that can be attributed to the intrinsic band-gap absorption of ZnO nanoparticles because of electron transfers from the valence band to the conduction band (O2p Zn3d). (Please see the revised manuscript)

5. The SEM image does not show nanoparticles. How you claim the aggrigates are nanoparticles? I think the image can be changed.

Author’s response: Thank you for your comments: Most ZnONPs were aggregated, according to the SEM image. the average particle size distribution of green ZnO NPs mainly around 37.493±2.205 nm According to our calculations using the "image J"  software. (Please see the revised manuscript)

6. What were the statistical methods for cytotaxicity and hemolysis methods?

Author’s response: Thank you for your comments: One-way ANOVA was employed in the statistical method to assess group differences, and the Student t-test and Tukey's test were applied to compare the groups.  The data were displayed as the mean ± SD of triplicates. (Please see the revised manuscript)

Minors:

1. Please check for typo or grammatical errors.

Author’s response: Thank you for your comments: The manuscript has been carefully edited and revised for typos or grammatical errors. (Please see the revised manuscript)

2. Please add the numbers for main functional groups for FTIR.

Author’s response: The FTIR data have been updated and the main functional group numbers have been included. (Please see the revised manuscript)

Author Response File: Author Response.pdf

Reviewer 2 Report

all comments were addressed

Author Response

Dear Editor and Reviewers,

Thank you for your letter and for the reviewers’ comments concerning our manuscript entitled “Biosynthesis of Zinc Oxide Nanoparticles using Capparis spinosa L. fruit extract: Their Characterizations, biocompatibility, and antioxidant activities”. Those comments are all really valuable and helpful in revising and improving our manuscript, as well as providing significant direction for our research. We carefully considered the comments and made changes that we hope will be approved. The revised sections of the document are highlighted in red. The followings are the main corrections in the manuscript and responses to the reviewers’ comments.

Reviewer #2:

 The presented manuscript includes the study of biosynthesis of zinc oxide nanoparticles using Capparis spinosa L. fruit extract: their characterizations, biocompatibility, and antioxidant activities.

The results of the work are presented on a good level but some questions and weak points should be mentioned.

1. Please, do not use more than 3 references in one place (like [1-4], [5-10], [13-17], etc.). Either you should describe the differences.

Author’s response: Thank you for your comments: We have arranged and described each reference in the text. (Please see the revised manuscript).

2. Please make subsection “2.1 Materials and reagents”. There please mention all used reagents in your study. Mention their provider, composition, and purity.

Author’s response: Thank you for your comments: “2.1 Materials and reagents” has been added to the material and methods section (Please see the revised manuscript)

3. Please show the exact planes in the XRD diffractogram (fig. 3), and mention the defined phases. Change “peak position (20)” to “2theta (degrees)”.

Author’s response: Thank you for your valuable comments: The exact planes have been added to the XRD diffractogram (Figure 3). and "peak position (20)" has been changed to "2theta (degrees)". (Please see the revised manuscript).

4. 4. Please highlight the waves mentioned in the text. It is a good practice to treat images.

Author’s response: Thank you for your valuable comments: The waves that are mentioned in the text have been identified in the updated Figure 4. (Please see the revised manuscript).

5. Please, delete Fig.6. It gives almost nothing and makes your paper looks worst (this is the usual practice of some authors in low-impact journals, looks as worst as the stretching of images). Instead of EDS spectra write one sentence in the text if there is really something to describe or just leave Table 1 (same, if it is really needed).

Author’s response: Thank you for your comments: Thank you for your valuable comments: We have removed Figure 6. and also table 1. (Please see the revised manuscript).

6. Particle size distribution and BET analysis are important for such kinds of experiments.

Author’s response: Thank you for your comments: While the suggested idea of considering adding BET analysis as a test for such kinds of experiments, seems interesting in studies dealing with green synthesis, However, the present study is mainly focused on the characterization and in vitro Evaluation of cytotoxicity, Hemolysis, and Antioxidant Properties. Therefore, we believe that adding BET analysis of our green ZnO NPs remains to be done in future papers.

7. The novelty of the paper is not clear. What are the benefits of your ZnO NPs compared with those obtained by other approaches?

Author’s response: Thank you for your comments, to our knowledge, the synthesis of ZnO NPs using C.spinosa L. and their cytotoxicity, Hemolysis, and Antioxidant Properties are not well documented.  

This is the first study that investigates the effect of employing C.spinosa L fruit extract as an effective reducing agent for the green chemistry synthesis of ZnO NPs. This part could reflect the novelty of our study.

8. All obtained results have to be compared with published analogs.

Author’s response: Thank you for your comments: The results and discussion sections have been updated by Comparing the obtained results to published analogs. (Please see the revised manuscript).

Author Response File: Author Response.pdf