Comparison of Antimicrobial Activity of Chitosan Nanoparticles against Bacteria and Fungi
, Xiaomin Wang 1,†, Xunlian Guo 1,3,†, Ping Yang 1, Jinze Yu 1,4,*, Yuru Shui 1, Cunkun Chen 1,4, Xuanlin Li 1, Qinglian Xu 1, Lin Xu 1, Xiufang Bi 1,2 and Xiaocui Liu 1,2Round 1
Reviewer 1 Report
The authors presented their original research article referring to the antimicrobial activity of chitosan nanoparticles against bacteria (E. coli & S. aureus) and fungi (P. steckii & A. oryzae). The research was also preceded by a microscopic and thermogravimetric analysis of the obtained nanoparticles. The article is interesting itself, but I believe it should be improved before publication in the Coatings journal.
Materials & Methods section:
1. Subsection 2.5. - Don't you think that adding 5 ml of CSNPs in solution with acetic acid and water to 5 ml of the nutrient broth will result in twice dilution of the medium components? Shouldn't a nutrient broth be used instead of water to dilute the CSNPs?
2. In blank control why was the water used instead of broth?
3. Section 2.6. - Why bacteria with OD = 0.7 were used?
4. Line 171 - How much mycelia were used for the test? All of the flask/plate in which they were grown or some specific amount?
5. Line 186 - Isn't 37 C too much for moulds growth?
Other suggestions:
- Figure 1 caption should be corrected. Subitems (a, b, c, and d) should be added, and it should be added that the first from the left are CSNPs.
- In the description of Figure 3, the change in absorbance around 325 nm has not mentioned in the text.
- It seems to me that in the case of Figure 7 a statistical analysis should be done.
- I believe that the discussion in this article should be elaborated upon.
Minor suggestions:
- Line 157 - double "therefore"
- Table 1 - It should be MBC instead of MFC.
- The unit of conductivity should be mS·cm-1.
- References should be improved according to “Instruction for authors”.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this article Liu and coworkers evaluate the antimicrobial activity of chitosan nanoparticles.
Even if it is not a very original proposal, the study is exhaustive, and the synthesis of the chitosan nanoparticles seems to be easy and reproducible fot other teams interested in this topic. For these reasons we consider that this article deserves to be published with minor revisions.
1. In the introduction, a scheme of the chitosan structural unit could be useful for non-specialists readers.
2. In line 253, the auhtors state:
3. "It was found that the coordination inducing effect of CSNP could dissociate the Trp and Tyr residues groups on the peptide chain of the BSA molecule and increase the absorrption intensity"
4. This is a key point in the article. The authors should provide solid references about it.
5. In line 258, the authors state:
6. "This suggests that the BSA was not only on the surface of the nanoparticles but also distributed in the outer hydrophilic layer. Therefore, the BSA carrying capacity of the nanoparticles could be termed as EE"
7. The authors link the BSA carrying capacity with the encapsulation efficiency. This relationship between these two parameters should be clarified.
8. Table 1 can be deleted given that the values are exactly the same for MIC and MFC, and they are already mentioned in the discussion.
9. The authors recognize that a more detailed investigation into the mechanism involved in the antimicrobial action of the chitosan nanoparticles is required. Some perspectives and future work in this line, should be included.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The manuscript has been carefully improved.
I have one suggestion - the reference list should be corrected - please see line 50 ("[divya2017]").
