Synthesis and Characterization of Bioactive Magnetic Nanoparticles from the Perspective of Hyperthermia Applications

Round 1

Reviewer 1 Report

The authors prepared iron oxide nanoparticles for hyperthermia applications from wormwood. Characterizations of these nanoparticles were conducted. This work is interesting and can be published after a revision of the following points.

 1. There is no experimental results prove that the magnetic nanoparticles are “superparamagnetic”. Of course，these nanoparticles are “magnetic”. I suggest a revision of the word “superparamagnetic” in the title and the text to “magnetic”.

2. Line 97, “manly” might be “mainly”? please check.

3.Line 137, “none of them did not evaluate”, delete “did not“？ Please check

 4. Line 157&268, ”Phisicochemical and physiochemical“ might be ”Physicochemical“? Please confirm.

 5. The main chemical reaction equations for the formation of the iron oxide nanoparticles during preparation should be provided.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Elena-Alina Moacă and colleagues' work is devoted to the synthesis of magnetic iron oxide nanoparticles using a new 'green' approach. In this approach, a plant extract of wormwood was used, which allowed, in particular, to control the size of the obtained nanoparticles. The magnetic and structural properties of the nanoparticles were studied and their influence on the efficiency parameter of magnetic hyperthermia SAR was determined. The work is interesting and well-organized, thus I recommend it for publication after considering the comments and answers to the questions listed below. 

1) Why did the authors use a ratio Fe3+:Fe2+ of 2.7 instead of the 2 (which corresponds to the stoichiometry of magnetite) usually used in the literature?

2) Which amount of bases were added to the plant extract and salt solution? What were the pH values before and after the addition of the bases to the salts and extract solutions? There is any difference in the pH level of leaf and stem extracts?

3) How were the nanoparticles washed from residual organics?

4) line 198: "...the inverse spinel structure of cubic magnetite..." please add "or maghemite". 

5) Please, enlarge the captions (all small text notes) on figures 3 and 4.

6) line 261: "Thermal decomposition of all magnetic nanoparticles...", in my view, there is no decomposition of magnetic particles but of organic content in samples.

7) line 304: "...presence of carbon in all samples is due to the tape...". Could the carbon be residual organics?

8) The authors refer to the particle sizes as determined by TEM, but no elaborated data are provided. If it is possible, please, indicate the average value of the particle size and polydispersity.

9) Lines 358-363 actually repeat what was already said in lines 333-342.

10) Same with lines 371-375, which repeat the discussion of EDX results.

11) Figure 11A and Table 2: Please, use one system of units, SI or CGS. Now the magnetization is in units of emu/g (CGS), whereas the field strength values are in A/m (SI). Simple change emu/g -> Am^2/kg.

12) Please, provide more informative relative values Mr/Ms in Table 2 instead of absolute values of residual magnetization Mr.

13) Please, check the text for minor typos and errors in English, for example:

line 97: manly -> mainly 

line 105: obtain -> obtained

line 291: shows -> show

line 334: confirms -> confirm

line 513:  morphologies -> morphology; was -> were 

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The authors presented the paper "Synthesis and characterization of bioactive superparamagnetic nanoparticles for hyperthermia applications"

1) Much more fresh 2-3 years paper should be presented in the Introduction section to show the area perspectives. There are a number of papers in 2022 about, for example, magnetic nanoparticles and hyperthermia in MDPI publisher or elsewhere. For example, see Magnetochemistry J. The references for cancer area is not new, too. For example, the references 2-9 may be changed on the recent review papers.

2) The authors proposed the use of their nanoparticles for hyperthermia applications. However, nanoparticles have to be used in the human organism. I don't see any investigations about stability, toxicity, etc. I recommend presenting any stability studies in water or an organism like conditions (pH, cell media, plasma, etc.). Nanoparticles may form some coating in organism media, which may lead to other hyperthermia effect.  I understand, that the authors discuss the synthesis and properties. However, some discussion in the Results and Discussion section should be added that your system will work with relevant references. 

3) The novelty and limitation of the work have to be added into the Conclusion section and the Abstract. There are many papers about magnetic nanoparticles for hyperthermia effect. Text editing of these sections may improve the significance of the paper.

4) Title. What the authors mean on the bioactivity. Specify, bioactivity is a broad word.

The authors haven't shown any biological experiments. In this way, I recommend to change by adding the word as a perspective for hyperthermia or smth. like this. But it is on your consideration.

Minor comment

NH4OH should be changed to NH3aq as in the ammonia solution only ~1% of NH4+ and OH- ions.

Figure 12 shows the bad linear correlation. Why it happens?

Figure 13B has bad resolution. I recommend dividing it into several pictures.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

Thank you for the revised paper.

Author Response

With great pleasure. We also thank you for reviewing our manuscript.

All the best!