Development of Adhesive, Bioactive and Antibacterial Titania Sol-Gel Coating on Titanium Substrate by Dip-Coating Technique

Round 1

Reviewer 1 Report

Dear Authors,

you describe the application of silver doped titania sol-gel coatings with and without hydroxyapatite on titanium samples. The morphology of the coatings is investigated by SEM, the adhesion by a tape test, the bioactivity in simulated body fluid and the antibacterial activity against escherichia coli. The results of this simple study are clearly represented, but some details have to be explained more exactly.

Some details should be improved:

1)In the abstract and the introduction the indices of the chemical formulars have to be set down.

2)introduction, line 52/53:

„not to use more than 1.6 ppm Ag“..regarding to what? The coating composition? Please explain this more exactly!

3)In the experimental the SEM-EDS-analysis is missed!

4) Experimental, line 67:

ref.(20-21), but ref.21 is missed in the references an ref.20 is incomplete!

5) Experimental, line 79:

please explain CFU !

6) Experimental, line 98-100, tape test:

here the number of the the ASTM-test should be noted! In the abstract it is not necessary!

7) Fig.2: The EDS results are very small, hard to discover.

8) Fig.3: The „needle-like crystals“ one can not find!

9) The conclusions should be a bit more extensive! Please give more specific information about your results!

 

 

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

below are my remarks and questions:

- All the comments are listed in the paper.

- Improve the English language and style.

- What is the thickness of the coatings?

- In order to see the advantages of the dip-coting method the measurement should be made with coatings obtained by some other method.

- Many citations are incorrect formatted.

 

Best regards

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The paper aims to describe the devolpment of a coatings containig silver and HA, tested for bioactvity and antibacterial properties, to be used for metallic materials.

However I have lot of concerns about the structure of the article and the contents.

• The aim of the study sounds not so innovative to me, and in the introduction section authors do not provide sufficient evidences of the scientific issue that such study should address. Surely, the field of coatings, able to guarantee implants biocompatibility and to prevent the onset of bacterial infection, is a challenge in the medical practice, but it's not clear the novelty and the improvement that the coating evaluated and the techniques used should provide. References are insufficient and not recent enough.
• In the introduction, you refer to "ethical reasons" for the use of SBF. What do you mean? The use of SBF can be surely useful for a first evaluation, but the use of preclinical model is still necessary to assess biocompatibility, activity and antibacterial efficacy of such implants.
• In the experimental part, samples have been grinded to homogenize surface. How did you assessed this?
• As for antibacterial study, did you use a material with proven antibacterial efficacy as control? 
• Why did you use E. Coli for antibacterial test? Considering the possible application in the orthopaedic field, you should discuss such choice considering other options more common in the prosthetic infection (e.g. S. Aureus)
• How did you evaluate the antibacterial effect of the tested samples? 
• No comparison and discussion with other similar studies (employing the same techniques for coating realization, similar materials or experimental set up) are reported. Limits in the results provided by the use of SBF are not described.

 

 

Author Response

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Round 2

Reviewer 2 Report

The revised manuscript significantly improved.

Author Response

Dear reviewer, 

thank you very much fot the positive review of the corrected manuscript.

Your sincerely

Diana Horkavcová

Reviewer 3 Report

The authors answered the questions . However, I still have few observations to point out:

• Despite the answer provided to my question, I still think that the absence of a positive control in the antibacterial efficacy study is something that,  if not recoverable with further experiments to be included in the paper, it must at least be discussed as a limitation of the study as it cannot compare the results obtained, albeit good, with a reference. Please add a statmente about this in the discussion section.
•  About the use of E. Coli for antibacterial test, I think that the bibliographic reference cited by the authors as response to my request should be added in the text as well as a statement about the possibility to perform further study with bacterial strains most frequently found in peri-prosthetic infection.
• The answer given about the absence of comparison with other studies is a very good point, and I think that adding these considerations in the paragraph of conclusion, emphasising the differences in methodology used, can give further strength to your work.

 

Author Response

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Author Response File: Author Response.docx