Antibacterial and Antifungal Activity of Novel Synthesized Neodymium-Substituted Cobalt Ferrite Nanoparticles for Biomedical Application
, Mohammad Azam Ansari 1,*, Mohammad A. Alzohairy 2, Mohammad N. Alomary 3, B. Rabindran Jermy 4, Raheem Shahzad 5, Neda Tashkandi 4 and Zainab Hassan Alsalem 1Round 1
Reviewer 1 Report
Dear author,
Congratulations on the results of your findings. There are a few things for you to consider.
In the title, consider changing Newly to Novel or Sonochemically. Newly is ok too. In the abstract and manuscript, do superscript and subscript all chemical formulae e.g. Cu2+ and CoNdxFe2. Line 30 change "a first report" to "the first report" In line 46, add in citation for extensively studied nanocrystalline ferrites. In line 51, add in "a" before "few strategies" Line 53, add in change "the change" to "any change". Line 79, add in amount of NaOH. Line 83, add in more details about centrifuge proces. Line 87, all brands and models should be in brackets. In line 82, remove "Further, the mixed...." as this has been reported in synthesis section. Instead, move the spectrophotometer from line 114 here. In line 109, in future, do fix the sonication time. In line 134, put PBS in brackets. In line 151, the sentence could be revised to "Agglomeration was also observed due to the magnetic nature of the product." In line 156, consider changing costless cost effective. Consider decreasing the scale in Fig 2A and 2B to be more suitable for the particle size. Consider increasing contrast for Fig 5A. Fig 5A caption, remove the repeated "The".
Author Response
Thank you reviewer for your comments, As per reviewer suggestions, all the correction has been done.
The changes in text have been made in red font, Fig 5A has also been modified.
Reviewer 2 Report
The manuscript entitled "Antibacterial and Antifungal Activity of Newly Synthesized Neodymium (Nd)-substituted Cobalt Ferrites Nanoparticles for Biomedical Application" deals with the evaluation of Neodymium substituted cobalt ferrites nanoparticle's evaluation as future candidates as both antibacterial and antifungal agents.
The subject is of high interest but the physico-chemical characterisation of the newly obtained materials needs major improvements. The manuscript cannot be accepted in this form. See comments below:
2.2 Instrumentation:
The authors state that: "The morphological, elemental and microstructural analyses of the products were analyzed by scanning electron microscopy (SEM, FEI Titan G2) equipped with energy-dispersive X-ray spectroscopy (EDX)"(pg2 lines 88-90) but to the best of my knowledge the equipment mentioned is a transmission electron microscope that can be operated also in STEM mode but it is not a scanning electron microscope.
3.1 Structural and morphological analysis along with EDX and Elemental mapping
Figure 1. What reference file was used for indexing the Co spinel ferrite crystalline phase? for the sample X=0.15 (blue line) I can se a quite well evidenced signal before the peak assigned to (220) peak that is less visible for the sample with x =0.20 an undepictable for the other two samples and that is why I do not agree wit the statement of the authors: "All the compositions exhibited the indexed peaks of Co spinel ferrite without presence of any secondary phase" (pg 4 lines 141-143)
at line 147 (pg4) the authors state that calculated average crystallite sizes are listed in table 1, table that I could not find in the manuscript!
Figure 2A The SEM images presented for the sample x=0.0 and x=0.1 are one and the same!
The agglomeration obtained from the TEM images (Figure 2B) i do not think that is due to magentic nature of the samples I think is related to the TEM sample preparation. What method was used? If the suspension drop casting was used this effect may appear when drying the grid for example.
The EDX spectra and the elemental maps were obtained on TEM or SEM equipment? why is not presented the actual electron image of the area investigated? The two images presented for oxygen of the two samples are again identical that is not possible....
Figure 3, optical density graph for S aureus the incubation times should be presented chronologically because it creates confusion.
Author Response
The manuscript entitled "Antibacterial and Antifungal Activity of Newly Synthesized Neodymium (Nd)-substituted Cobalt Ferrites Nanoparticles for Biomedical Application" deals with the evaluation of Neodymium substituted cobalt ferrites nanoparticle's evaluation as future candidates as both antibacterial and antifungal agents.
The subject is of high interest but the physico-chemical characterisation of the newly obtained materials needs major improvements. The manuscript cannot be accepted in this form. See comments below:
2.2 Instrumentation:
Comments: The authors state that: "The morphological, elemental and microstructural analyses of the products were analyzed by scanning electron microscopy (SEM, FEI Titan G2) equipped with energy-dispersive X-ray spectroscopy (EDX)"(pg2 lines 88-90) but to the best of my knowledge the equipment mentioned is a transmission electron microscope that can be operated also in STEM mode but it is not a scanning electron microscope.
Response: Thank you reviewer for this suggestion. The instrument utilized for SEM and TEM analysis has been corrected in our revised version.
3.1 Structural and morphological analysis along with EDX and Elemental mapping
Figure 1. What reference file was used for indexing the Co spinel ferrite crystalline phase? for the sample X=0.15 (blue line) I can see a quite well evidenced signal before the peak assigned to (220) peak that is less visible for the sample with x =0.20 an undepictable for the other two samples and that is why I do not agree wit the statement of the authors: "All the compositions exhibited the indexed peaks of Co spinel ferrite without presence of any secondary phase" (pg 4 lines 141-143)
at line 147 (pg4) the authors state that calculated average crystallite sizes are listed in table 1, table that I could not find in the manuscript!
Response: Thank you. X-ray diffraction pattern of all samples were analysed for peaks matching Co spinel ferrite using FullProf Program, Rietveld analysis. The program confirmed the purity and also matched the profile corresponding to pure spinel ferrites. Therefore, we like to retain the statement without modifications. The average crystallite size is in the range of 9-16 nm. The sentence has been revised.
Figure 2A The SEM images presented for the sample x=0.0 and x=0.1 are one and the same!
Response: We like to thank the reviewer for the important suggestion. The SEM image for x=0.1 has been inserted in the revised version.
The agglomeration obtained from the TEM images (Figure 2B) i do not think that is due to magentic nature of the samples I think is related to the TEM sample preparation. What method was used? If the suspension drop casting was used this effect may appear when drying the grid for example.
Response: Thank you reviewer. The samples for TEM were prepared by dropping particle dispersions onto carbon-coated Cu grids and air-dried before mounting onto the microscope. However, the agglomeration observed in present study is usually expected for this type of magnetic nanoparticles. In order to prevent agglomeration, synthesis technique has to be modified using specific medium like sodium dodecyl sulfate (NaDS)/oleic acid or microwave assisted synthesis [1].
K. Maaz, Arif Mumtaz, S.K. Hasanain, Abdullah Ceylan, Synthesis and magnetic properties of cobalt ferrite (CoFe2O4) nanoparticles prepared by wet chemical route, Journal of Magnetism and Magnetic Materials 308 (2007) 289–295.
The EDX spectra and the elemental maps were obtained on TEM or SEM equipment? why is not presented the actual electron image of the area investigated? The two images presented for oxygen of the two samples are again identical that is not possible....
Respnse: The EDX spectra was recorded using SEM equipment. The error in experimental part has been modified in our revised version. The images of area investigated are of entire range of SEM images (Figure 2A). There is a variation in cps value to oxygen but the difference is too low for significant variation for the images. However, the intensity of Nd appears higher with x = 0.2 than 0.1.
Figure 3, optical density graph for S aureus the incubation times should be presented chronologically because it creates confusion.
Response: Thank you reviewer for this observation, fig has been changed
The English language has been improve through out the manuscript.
Reviewer 3 Report
The synthesis of different families of cobalt ferrite nanoparticles and the search of possible technological applications for the resulting materials is not a new subject. The use of these nanoparticles for biomedical applications is also not a new idea.
However, the research shown in this manuscript seems to indicate that the authors have obtained new and interesting results with some value and possibilities of being finally applied in the field of biomedical technologies. The characterization techniques chosen for the development of the study have been very adequate and the material has been satisfactorily characterized. The presentation of the results is also correct and successful.
In the opinion of this reviewer, the most innovative aspects of this research are related with the improvement of the antibacterial and antifungal ability of cobalt ferrite nanoparticles by using neodymium as a substitution agent into cobalt ferrite matrix.
However, this reviewer believes that the authors could improve the quality and scientific interest of this work taking into account some issues closely related to this research:
Make a brief comparison between the advantages and limitations of the sonochemical method and other conventional synthesis methods reported by the scientific literature. It would be interesting not just to cite other preparation methods of modified cobalt ferrite nanoparticles (i.e. sol-gel method and the method of co-precipitation, etc), but also briefly describe the different structural characteristics and the resulting properties of the modified cobalt ferrite nanoparticles as a function of the synthesis method used to obtain these materials without forgetting the benefit of being able to modulate thee characteristics for possible technological applications.
The following list of bibliographical references could be interesting to try to improve the contents of the Introduction and the Discussion of Results of this paper.
Preparation methods:
Avazpour, L., Shokrollahi, H., Toroghinejad, M.R., Zandi Khajeh, M.A., Effect of rare earth substitution on magnetic and structural properties of Co1-xREx Fe2O4 (RE: Nd, Eu) nanoparticles prepared via EDTA/EG assisted sol-gel synthesis, (2016) Journal of Alloys and Compounds, 662, pp. 441-447.
Nikumbh, A.K., Pawar, R.A., Nighot, D.V., Gugale, G.S., Sangale, M.D., Khanvilkar, M.B., Nagawade, A.V., Structural, electrical, magnetic and dielectric properties of rare-earth substituted cobalt ferrites nanoparticles synthesized by the co-precipitation method,(2014) Journal of Magnetism and Magnetic Materials, 355, pp. 201-209.
Routray, K.L., Saha, S., Sanyal, D., Behera, D., Role of rare-earth (Nd 3+ ) ions on structural, dielectric, magnetic and Mossbauer properties of nano-sized CoFe 2 O 4 : Useful for high frequency application
(2019) Materials Research Express, 6 (2), art. no. 026107,
Xavier, S., Thankachan, S., Jacob, B.P., Mohammed, E.M., Structural and electrical properties of neodymium substituted cobalt ferrite nanoparticles, (2015) IOP Conference Series: Materials Science and Engineering, 73 (1), art. no. 012093, .
Biomedical Aplications:
Amiri, S., Shokrollahi, H., The role of cobalt ferrite magnetic nanoparticles in medical science, (2013) Materials Science and Engineering C, 33 (1), pp. 1-8.
Sanpo, N., Berndt, C.C., Wen, C., Wang, J., Transition metal-substituted cobalt ferrite nanoparticles for biomedical applications, (2013) Acta Biomaterialia, 9 (3), pp. 5830-5837.
Hathout, A.S., Aljawish, A., Sabry, B.A., El-Nekeety, A.A., Roby, M.H., Deraz, N.M., Aly, S.E., Abdel-Wahhab, M.A., Synthesis and characterization of cobalt ferrites nanoparticles with cytotoxic and antimicrobial properties. (2017) Journal of Applied Pharmaceutical Science, 7 (1), pp. 86-92. Cited 6 times.
Samavati, A., F. Ismail, A., Antibacterial properties of copper-substituted cobalt ferrite nanoparticles synthesized by co-precipitation method
(2017) Particuology, 30, pp. 158-163
Maksoud, M.I.A.A., El-Sayyad, G.S., Ashour, A.H., El-Batal, A.I., Elsayed, M.A., Gobara, M., El-Khawaga, A.M., Abdel-Khalek, E.K., El-Okr, M.M., Antibacterial, antibiofilm, and photocatalytic activities of metals-substituted spinel cobalt ferrite nanoparticles, (2019) Microbial Pathogenesis, 127, pp. 144-158
Ashour, A.H., El-Batal, A.I., Maksoud, M.I.A.A., El-Sayyad, G.S., Labib, S., Abdeltwab, E., El-Okr, M.M., Antimicrobial activity of metal-substituted cobalt ferrite nanoparticles synthesized by sol–gel technique, (2018) Particuology, 40, pp. 141-151.
Author Response
The synthesis of different families of cobalt ferrite nanoparticles and the search of possible technological applications for the resulting materials is not a new subject. The use of these nanoparticles for biomedical applications is also not a new idea.
However, the research shown in this manuscript seems to indicate that the authors have obtained new and interesting results with some value and possibilities of being finally applied in the field of biomedical technologies. The characterization techniques chosen for the development of the study have been very adequate and the material has been satisfactorily characterized. The presentation of the results is also correct and successful.
In the opinion of this reviewer, the most innovative aspects of this research are related with the improvement of the antibacterial and antifungal ability of cobalt ferrite nanoparticles by using neodymium as a substitution agent into cobalt ferrite matrix.
However, this reviewer believes that the authors could improve the quality and scientific interest of this work taking into account some issues closely related to this research:
Make a brief comparison between the advantages and limitations of the sonochemical method and other conventional synthesis methods reported by the scientific literature. It would be interesting not just to cite other preparation methods of modified cobalt ferrite nanoparticles (i.e. sol-gel method and the method of co-precipitation, etc), but also briefly describe the different structural characteristics and the resulting properties of the modified cobalt ferrite nanoparticles as a function of the synthesis method used to obtain these materials without forgetting the benefit of being able to modulate thee characteristics for possible technological applications.
The following list of bibliographical references could be interesting to try to improve the contents of the Introduction and the Discussion of Results of .this paper
Response: We would like to thank the reviewer for the important suggestions and for providing the references. The manuscript has been modified using the given references
Preparation methods:
Avazpour, L., Shokrollahi, H., Toroghinejad, M.R., Zandi Khajeh, M.A., Effect of rare earth substitution on magnetic and structural properties of Co1-xREx Fe2O4 (RE: Nd, Eu) nanoparticles prepared via EDTA/EG assisted sol-gel synthesis, (2016) Journal of Alloys and Compounds, 662, pp. 441-447.
Nikumbh, A.K., Pawar, R.A., Nighot, D.V., Gugale, G.S., Sangale, M.D., Khanvilkar, M.B., Nagawade, A.V., Structural, electrical, magnetic and dielectric properties of rare-earth substituted cobalt ferrites nanoparticles synthesized by the co-precipitation method,(2014) Journal of Magnetism and Magnetic Materials, 355, pp. 201-209.
Routray, K.L., Saha, S., Sanyal, D., Behera, D., Role of rare-earth (Nd 3+ ) ions on structural, dielectric, magnetic and Mossbauer properties of nano-sized CoFe 2 O 4 : Useful for high frequency application
(2019) Materials Research Express, 6 (2), art. no. 026107,
Xavier, S., Thankachan, S., Jacob, B.P., Mohammed, E.M., Structural and electrical properties of neodymium substituted cobalt ferrite nanoparticles, (2015) IOP Conference Series: Materials Science and Engineering, 73 (1), art. no. 012093, .
Biomedical Aplications:
Amiri, S., Shokrollahi, H., The role of cobalt ferrite magnetic nanoparticles in medical science, (2013) Materials Science and Engineering C, 33 (1), pp. 1-8.
Sanpo, N., Berndt, C.C., Wen, C., Wang, J., Transition metal-substituted cobalt ferrite nanoparticles for biomedical applications, (2013) Acta Biomaterialia, 9 (3), pp. 5830-5837.
Hathout, A.S., Aljawish, A., Sabry, B.A., El-Nekeety, A.A., Roby, M.H., Deraz, N.M., Aly, S.E., Abdel-Wahhab, M.A., Synthesis and characterization of cobalt ferrites nanoparticles with cytotoxic and antimicrobial properties. (2017) Journal of Applied Pharmaceutical Science, 7 (1), pp. 86-92. Cited 6 times.
Samavati, A., F. Ismail, A., Antibacterial properties of copper-substituted cobalt ferrite nanoparticles synthesized by co-precipitation method
(2017) Particuology, 30, pp. 158-163
Maksoud, M.I.A.A., El-Sayyad, G.S., Ashour, A.H., El-Batal, A.I., Elsayed, M.A., Gobara, M., El-Khawaga, A.M., Abdel-Khalek, E.K., El-Okr, M.M., Antibacterial, antibiofilm, and photocatalytic activities of metals-substituted spinel cobalt ferrite nanoparticles, (2019) Microbial Pathogenesis, 127, pp. 144-158
Ashour, A.H., El-Batal, A.I., Maksoud, M.I.A.A., El-Sayyad, G.S., Labib, S., Abdeltwab, E., El-Okr, M.M., Antimicrobial activity of metal-substituted cobalt ferrite nanoparticles synthesized by sol–gel technique, (2018) Particuology, 40, pp. 141-151.
Round 2
Reviewer 2 Report
The manuscript was improved from the previous version.
I have a few minor observations regarding this version of the manuscript
The legend for figure 2A appears twice, once where it should be and once on the third SEM image.
Figure 3. I think that is enough to present only the EDS spectra with the corresponding elemental quantification if no additional information can be depicted from the elemental mapping as the authors argue in the reply to my first report.
Author Response
Comments and Suggestions for AuthorsThe manuscript was improved from the previous version.
I have a few minor observations regarding this version of the manuscript
1- The legend for figure 2A appears twice, once where it should be and once on the third SEM image.
Reply: Yes, you are correct, there were two legends for Figure 2 A. In the revised manuscript it has been corrected.
Figure 3. I think that is enough to present only the EDS spectra with the corresponding elemental quantification if no additional information can be depicted from the elemental mapping as the authors argue in the reply to my first report.
Reply: AS per reviewer suggestion, only the EDS spectra has been shown for Figure 3 in the revised manuscript.
