Biofabricated Aluminium Oxide Nanoparticles Derived from Citrus aurantium L.: Antimicrobial, Anti-Proliferation, and Photocatalytic Efficiencies
Round 1
Reviewer 1 Report
Comments:
Biofabricated Aluminium oxide nanoparticles derived from 2 Citrus aurantium L.: Antimicrobial, Anti-proliferation and Photocatalytic efficiencies
1. Write the genus names and species names in the italic form such as Citrus aurantium, Staphylococcus aureus, Staphylococcus epidermis etc.
2. The antimicrobial efficiencies data in the abstract and results and discussion section data are not matching. Correct it.
3. In the abstract “Al2O3” change to “Al2O3”.
4. In the abstract “In this study, Al2O3 NPs were found to have an average crystallite size was 28 nm in the XRD and 322 nm in the UV spectrum, and peaks at 406 and 432 in the FT-IR spectra, which were ascribed to the stretching of aluminium oxide.” – modify the sentence appropriately.
5. Introduction is too short, so increase the introduction part.
6. Write down all the chemicals used in the experiment and include them in the manuscript.
7. In the Synthesis of aluminium oxide nanoparticles section- “A solution of 0.5 M potassium aluminium sulphate is diluted in 100 mL of double distilled water”. What is the meaning of it? whether the author diluted the 0.5 M potassium aluminium sulphate solution or prepared 0.5 M potassium aluminium sulphate solution by dissolving an appropriate amount of potassium aluminium sulphate in 100 mL distilled water.
8. “2 g of sodium hydroxide should be gradually added to the zinc acetate solution”- what is the concentration or quantity of zinc acetate solution?
9. Why the author used zinc acetate solution? Where did the author use the above-prepared potassium aluminium sulphate solution?
10. How PH was maintained 12. write in detail, so others can repeat the experiment, it will increase your citation.
11. By taking note of all the above points, rewrite the Synthesis of aluminium oxide nanoparticles again.
12. In line 97 “35°C” change to “35 °C”. check for typo errors.
13. How was the UV-vis absorption spectroscopy experiment carried out? Measured for solids or dilution solution?
14. In the UV-vis absorption section, the author mentioned UV-vis spectroscopy and photoluminescence spectroscopy were used to demonstrate the optical property of the biofabricated Al2O3 NPs at room temperature. Where is the photoluminescence data in the manuscript?
15. In FTIR measurement, which method did you use to analyze it?
16. Photocatalytic experiment was not clear. Write in detail how much Methylene blue and catalyst are used and what source of light is used for degradation.
17. The author should increase the quality of the manuscript by elaborating results and discussion and citing more references and comparing your results with others work.
Author Response
As per your suggestion has been carried out.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The contribution is original & sound. It reports on bio-engineered nanoscaled Al2O3 using Citrus aurantium peel extract as aneffective chelating agent. The reported results are comprehensive & complementary in support of the various discussions within the manuscript as well as the draw conclusions. Hence, this contribution is recommended for publication once the following Precisions (P), Corrections (C) & Recommendations (R) are considered and addressed each & All:
PCR-0:
Considering the large optical bandgap of Al2O3 polymorphs ranging in between 5.1 to 6 eV, how can the photocatalytic response can bw explained as sustained by Figure 7!!!!!!!!!!!. This is an unexpected response!!!!!!!!!!!!!!
PCR-1:
While the reported results are sound , the authors have ommitted to discuss the mechanism of the biosynthesis or at at least highlight the major likely potential phytocompounds involved in the chelation reduction process of the Al precursor. In this regard, the authors are encouraged to refer to the following publications that they should included in their discussion & add them in their reference section:
(i)ZnO nanoparticles via Moringa oleifera green synthesis: Physical properties & mechanism of formation, N Matinise, XG Fuku, K Kaviyarasu, N Mayedwa, Applied Surface Science 406, 339-347(2017)
(II)Biosynthesis of iron oxide (Fe2O3) nanoparticles via aqueous extracts of Sageretia thea (Osbeck.) and their pharmacognostic properties, AT Khalil, M Ovais, I Ullah, M Ali, ZK Shinwari, Green Chemistry Letters and Reviews 10 (4), 186-201(2017)
(iii)Green synthesis of nickel oxide, palladium and palladium oxide synthesized via Aspalathus linearis natural extracts: physical properties & mechanism of formation, N Mayedwa, N Mongwaketsi, S Khamlich, K Kaviyarasu, N Matinise, ... Applied Surface Science 446, 266-272(2018),
PCR-2:
It is established that alumina polymorphs' band gap values range from 5.54 eV to about 6.41 eV. Hence, it would havde been ideal to deduce the optical bandgapo of the current Al2O3 nanoparticles using the Tau's approximation!
PCR-3:
One should correct "2.3. Synthesize of aluminium oxide nanoparticles" as "2.3. Synthesis of aluminium oxide nanoparticles"
PCR-4:
In the EDAX chemical spectrum of of Figure 2(b), there are 2 intense peaks unidentified? they are located at the vicinity of approximately 2.85keV and 3.9keV. what are they?
PCR-5:
Figures 5 & 6 confirm both the antibacterial effectiveness of the bioengineered Al2O3 against several species. I|t would be sound to compare such a sound response to recent tly published literature on standard nano-oxides such as Fe2O3 & CeO2. In this regard, the authors are encouraged to refer to the following publications that they should included in their discussion & add them in their reference section:
(i)Ditlopo, N., Sintwa, N., Khamlich, S. et al. From Khoi-San indigenous knowledge to bioengineered CeO2 nanocrystals to exceptional UV-blocking green nanocosmetics. Sci Rep 12, 3468 (2022). https://doi.org/10.1038/s41598-022-06828-x
PCR-6:
While the reported results are sound , the authors have ommitted to discuss the mechanism of the biosynthesis or at at least highlight the major likely potential phyto-compounds involved in the chelation reduction process of the Al precursor. In this regard, the authors are encouraged to refer to the following publications that they should included in their discussion & add them in their reference section:
(i)ZnO nanoparticles via Moringa oleifera green synthesis: Physical properties & mechanism of formation, N Matinise, XG Fuku, K Kaviyarasu, N Mayedwa, Applied Surface Science 406, 339-347(2017)
(II)Biosynthesis of iron oxide (Fe2O3) nanoparticles via aqueous extracts of Sageretia thea (Osbeck.) and their pharmacognostic properties, AT Khalil, M Ovais, I Ullah, M Ali, ZK Shinwari, Green Chemistry Letters and Reviews 10 (4), 186-201(2017)
(iii)Green synthesis of nickel oxide, palladium and palladium oxide synthesized via Aspalathus linearis natural extracts: physical properties & mechanism of formation, N Mayedwa, N Mongwaketsi, S Khamlich, K Kaviyarasu, N Matinise, ... Applied Surface Science 446, 266-272(2018)
PCR-7
In view of the multifunctional photocaltaly & antibacterial responses exhbited by the Al2O3 bio-engineered using Citrus aurantium peel extract. Would it be possible to using this natural extract to bio-engineer other nanoscaled oxides such as VO2, CuO, Fe2O3,NiO, ZrO2 & others,...... It would be sound to include such a foresight discussion at the end section of the manuscript just before the conclusion section. In this regard, the authors are encouraged to refer to the following publications that they should included in their discussion & add them in their reference section:
(i)Stalling behaviour of chloride ions: a non-enzymatic electrochemical detection of α-Endosulfan using CuO interface
SS Rathnakumar, K Noluthando, AJ Kulandaiswamy, JBB Rayappan, ... Sensors and Actuators B: Chemical 293, 100-106(2019)
Author Response
As per your suggestion has been carried out.
Author Response File: Author Response.pdf
Reviewer 3 Report
The work seems interesting regarding its results and suggested production methods. However, there are some major points that the authors should clarify before acceptance.
The major points have been stated as follows:
1. I'm not a specialist in English grammar, but here something is wrong. The language of the manuscript is not well understood. the manuscript should be proofread linguistically and presented to a specialist to rewrite many paragraphs
2. L 14, 17, 18, 21 and 28: Pls, replace "Al2O3" with " Al2O3"
3. L 27 : Pls, Add and complete the sentence…..were utilized to assess the morphology, structural and optical properties of Al2O3 NPs
4. L 21 and L22 need to be rewritten "In this study, Al2O3 NPs were found to have an average crystallite size was 28 nm in the XRD 21 and 322 nm in the UV spectrum, and peaks at 406 and 432 in the FT-IR spectra, which were ascribed 22 to the stretching of aluminium oxide". The abstract contain errors, and for sure they are badly explained
5. L64 As far as I understand, the authors use potassium aluminium sulphate as precursor for aluminium ions, what the authors mean in this sentence: " gradually added to the zinc acetate 64 solution"? From a chemical point of view, this sentence should be removed as a compromising error, because potassium aluminium sulphate was used as precursor for aluminium ions....
6. L65 4 g of sodium hydroxide was then gradually added after that????. Why add sodium hydroxide again????
7. There is no evidence on the antibacterial effect (no photos for the inhibition zones).
8. The authors must Add more information on the antibacterial and antioxidant activity of biosynthesized Aluminium oxide nanoparticles in the introduction.
9. The methodology of antibacterial testing is not clearly described. What was tested? Plant extract? Nanoparticles? Together or separately? Gram- and gram+ bacteria should be distinguished in the methodology. what type of bacterial strain were used? The authors must verify the strains (such as ATCC or ECACC or other verified strains).
10. EDX analysis: where the weight and atomic percentage ratio for aluminium and oxygen?
11. It seems that the authors did not check the purity of their nanoparticles (by the way, was it performed with subsequent centrifugations? it is not clear from the text). It is important that the authors can provide a measurement of the purity of their product, especially considering the in vitro tests.
12. What is then the mechanism of the biosynthesis; is it a pre reduction of pure chaelation process?. It is necessary to at least propose the likely potential mechanism of the biosynthesis via the natural extarcts from the Citrus aurantium peel extract.
13. Please fully explain the statistical analysis in the working method.
14. Conclusions too short.
Author Response
As per your suggestion has been carried out.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The revised version has addressed the raised points. Hence it is recomended for publication as is.
Reviewer 3 Report
I believe this paper has been sufficiently improved and it is suitable to puplish in9i sustainability
