Biocidal Coatings against Gram-Positive Bacteria from Linear and Branched Polycations: The Decisive Role of the Diffusion Coefficients of Macromolecules
, Valeria I. Marina 1,2, Anastasia V. Bolshakova 1, Anna K. Berkovich 1, Oksana A. Kuznetsova 3, Anastasia A. Semenova 3, Yulia K. Yushina 3, Dagmara S. Bataeva 3, Maria A. Grudistova 3 and Andrey V. Sybachin 1,*
Round 1
Reviewer 1 Report
This paper compares mechanical and antibacterial properties of the polymer films prepared from polycations with different structure and molecular weight. The swelling behavior, adhesion strength, wash-off resistance and antibacterial activity of the biocidal coatings were studied using a number of physical methods. The data obtained revealed the interdependencies between the above parameters, which can be helpful in the development of the novel biocidal coatings for food processing and packaging. The results are clearly presented and thoroughly discussed, while the conclusions are rather convincing and reliable. So, the paper can be recommended for publication in Coatings after correcting the axis labels in Fig. 2a.
Comments for author File: 
Comments.pdf
The overall level of the English language in the manuscript is rather high, but there are several grammatical errors within the text which should be corrected during a careful proofreading.
Author Response
The corrections were made.
We thank the Reviewer for the payed attention to our research.
Reviewer 2 Report
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Comments for author File: Comments.pdf
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Author Response
- The abstract is too long; it is exceeding the number of maximum words admitted (200 words).
Answer: Abstract was shortened to fit the requirements
- Line 55 – the bacteria should be written with italics; same for lines 90-91;
Answer: Correction was made
- Line 68 – space after the word ~polymers~.
Answer: Correction was made
- Lines 104-111 the text is not justified;
Answer: Correction was made
- The structure for PEI and PDADMAC should have the same font size (I suggest palatino linotype), and they should appear as recommended in the coatings template: (a) (b)
Answer: The Figures were redrawn and presented according to suggestion.
- The axes name for Figures 2a and 2 b, are too big in comparison with the content, also, the name of the y axe in Figure 2. a is not complete! Please center the axes' names!
Answer: Correction was made
- Figure 3, center the y axe;
Answer: Correction was made
- Delete the empty lines 292-295;
Answer: Correction was made
- Line 306 0 space after the word ~observed~;
Answer: Correction was made
- In Figures 4a and 4b the name of the axes are too large.
Answer: Correction was made
- Delete the free rows 305-306;
Answer: Correction was made
- Line 306 should be deleted;
Answer: Correction was made
13-15 What are the limitation of the study? .The coating procedure can be reproduced at a higher scale? What does it add to the subject area compared with other published material?
Answer: The upscaling of any laboratory research is the specific cost-required task. However, we have tested the application of the sprayer with electric pump and nozzle 0.15 cm to cover large areas of glass and ceramics on the floor and walls with protective polyelectrolyte coating. Now we study the optimal recipe consumption, the sizes of nozzles, pressure of pump and other details to upscale the lab research.
Here we investigate the properties of coatings of two types of polycations. The broad spectrum of molecular weights of samples allows us to determine the critical degrees of polymerization that are suitable for formation of coatings with fine mechanical and antibacterial properties. In order to direct compare of polycations with different architecture and chemistry the degree of polymerization or molecular weight are not the adequate parameters. We have estimated that diffusion coefficients of macromolecules could be used as this key parameter. Polymers with effective antibacterial properties but with short length are not suitable for the formation of protective biocide coatings.
In addition, the discussion section was expanded with analysis of the works in field of protective coatings.
- What is the composition of the microspheres? Are the ingredients included in the microsphere compatible with the ones used in this study? Have you verified if some ingredient from the microsphere is interfering with the biocide activity (is there any influence)?
Answer: The latex microspheres are conventional polystyrene latexes for phagocytosis. In our experiments, we use latexes to simulate interaction of bacteria membrane with polyelectrolyte coatings. For this purpose, the surface of latex was completely covered with lipid bilayer by procedure described in ref. 34. With the help of modified microspheres, we demonstrate the electrostatic adsorption of biomimetic membranes on polyelectrolyte coatings. So, these microspheres are not the part of biocidal coating, and their impact on biocide activity is out of scope of the research.
- High space between lines 486 and 487!
Answer: Correction was made
- Reference 34 is not complete!
Answer: Correction was made
- Self-citation is detected in the article (four articles are cited in the reference). Please verify if they need to be cited!
Answer: The generally accepted requirement for the regular article type of manuscript that level of self-citation should not exceed 20%. In our manuscript the level of self-cited articles less than 12%. Ref. 24,25,28 contain the information polycations of this very study and their antibacterial properties. Ref. 24, 34, 35 cite methodological details of the experiments. Ref. 46 cites the data on properties and biocide activity of hyperbranched polyelectrolyte with quaternary ammonium groups to compare them with the data about current objects of study.
We thank the Reviewer for the remarks, corrections and questions.
Reviewer 3 Report
Manuscript ID: coatings-2402120
Title: Biocide coatings against Gram-positive bacteria from linear and branched polycations. The decisive role of the diffusion coefficients of macromolecules
The paper entitled “Biocide coatings against Gram-positive bacteria from linear and branched polycations. The decisive role of the diffusion coefficients of macromolecules” by Andrey V. Sybachin and his coworker reported an interesting experimental and modelling discussion in the properties of branched polyethyleneimine (PEI) and linear polydiallyldimethylammonium chloride (PDADMAC) coatings with different molecular weights of polymers to determine their suitability as stable coatings with antibacterial properties against foodborne bacteria. The finding is significant in manipulating the coating technology for biological bacteria. Although the paper is not a pioneer work in biological interaction, it demonstrates the use of simple biocide coatings on treat surface through various techniques forming a film.
This manuscript should be revised according to the following comments:
1. This article needs to try to draw a schematic diagram representing the core of this research. In particular, it is necessary to further link the meaning of these pictures. Please improve the content of this section.
2. The Abstract part is too tedious to read. Please modify it.
3. The interaction between materials and organisms is very important in this paper. Please add to this part of the discussion.
4. The manuscript should include a more thorough background on related works in literatures. Although the manuscript has cited several papers, it did not cover many references reporting new developments, such as those in Coatings 2023, 13(4), 766; Coatings 2023, 13(3), 582; ACS Applied Bio Materials 2019, 2, 11, 4801–4811; ACS Applied Bio Materials 2022, 5, 1073–1083; Polymers 2023, 15(4), 1047.
5. Overall, it is recommended for publication in the Coatings after the major revisions.
Author Response
- This article needs to try to draw a schematic diagram representing the core of this research. In particular, it is necessary to further link the meaning of these pictures. Please improve the content of this section.
Answer: The Graphical Abstract was added
- The Abstract part is too tedious to read. Please modify it.
Answer: Abstract was shortened to fit the requirements
- The interaction between materials and organisms is very important in this paper. Please add to this part of the discussion.
Answer: The discussion section was broadened with the required data.
- The manuscript should include a more thorough background on related works in literatures. Although the manuscript has cited several papers, it did not cover many references reporting new developments, such as those in Coatings 2023, 13(4), 766; Coatings 2023, 13(3), 582; ACS Applied Bio Materials 2019, 2, 11, 4801–4811; ACS Applied Bio Materials 2022, 5, 1073–1083; Polymers 2023, 15(4), 1047.
Answer: The suggested references were used in discussion section.
Round 2
Reviewer 3 Report
The MS was properly revised according to the reviewers' suggestions. I recommend its publication without any further changes.
