Revisiting Tetra-p-Sulphonated Porphyrin as Antimicrobial Photodynamic Therapy Agent

Round 1

Reviewer 1 Report

This report relates to use of photodynamic therapy for eradication of microorganisms. The text is generally adequate although there are instances where someone more familiar with English needs to provide a bit of editing. An early example is shown in line 27 where ‘able’ should be replaced by ‘capable’. Line 44, delete ‘as’. There are other examples throughout the text. Check spelling of ‘continuous’ (line 330). What are HSA biological structures (line 312)? Line 383 is in another language. 

As a review, this summarizes current knowledge relating to efficacy of some  photosensitizing agents on microbial targets. Something neglected is the effect of wavelength of excitation on efficacy. If treatment of infections is considered, wavelengths shorter than 600 nm penetrate tissues poorly. The major intent appears to be in the direction of viral eradication on surfaces (masks, suits, gloves) which is reasonable although use of other agents, e.g., ethanol, might be equally effective for some of these purposes. I don’t see how PDT is going to be useful for viral eradication in water and air (line 537).  

Author Response

Dear Reviewer,

Thank you for your evaluation and for the suggestions to improve the quality of my paper.

I will answer at your questions and corrections.

1. This report relates to use of photodynamic therapy for eradication of microorganisms. The text is generally adequate although there are instances where someone more familiar with English needs to provide a bit of editing.

I went through the whole article and corrected the sentences and expressions that did not seem correct in English.

2. An early example is shown in line 27 where ‘able’ should be replaced by ‘capable’.

Done

3. Line 44, delete ‘as’.

Done

4. There are other examples throughout the text. Check spelling of ‘continuous’ (line 330).

Done

5. What are HSA biological structures (line 312)?

HSA = Human serum albumine. I inserted in the text the explanation.

6. Line 383 is in another language. 

I checked and corrected. Thank you!

7. As a review, this summarizes current knowledge relating to efficacy of some  photosensitizing agents on microbial targets. Something neglected is the effect of wavelength of excitation on efficacy. If treatment of infections is considered, wavelengths shorter than 600 nm penetrate tissues poorly.

A short sub-chapter about the effect of excitation wavelength on the efficacy of some  photosensitizing agents on microbial targets has been included in the text. Also, the light sources chapter has been included in the text.

8. The major intent appears to be in the direction of viral eradication on surfaces (masks, suits, gloves) which is reasonable although use of other agents, e.g., ethanol, might be equally effective for some of these purposes. I don’t see how PDT is going to be useful for viral eradication in water and air (line 537).  

We have inserted some relevant paragraphs with specific references, explaining how photodynamic treatment (PDT), using photosensitizers, such as positively charged porphyrin, can help attenuate COVID-19, with potential activity, namely to disinfect surfaces, water and air. Unfortunately, due to limited work in this area, I only had to use the papers I found. My goal was not to develop wastewater treatment processes that effectively inactivate this virus. I discussed the potential use of this positively charged double-charged porphyrin to generate singlet oxygen during light irradiation, with longer activity than ethanol (highly volatile solvent). I wish I had been convincing in presenting this part of my paper.

Author Response File: Author Response.docx

Reviewer 2 Report

In the review entitled “REVISITING TETRA-p-SULPHONATED PORPHYRIN AS ANTIMICROBIAL PHOTODYNAMIC THERAPY AGENT,” the author describes not only the research area of the given title but also broad topics on antimicrobial photodynamic therapy - from the history of sunbathing healthcare in the ancient China, India, Egypt, or Greece to the future application of photodynamic therapy for a new COVID-19 treatment. It seems that the author pays too much attention to trifling details and misses the big picture. Overall, the manuscript is very rambling and difficult to follow. The topic is interesting but the manuscript does not communicate it well. Therefore, the author should rewrite the manuscript to concentrate on the main point of the discussion.

Author Response

Dear Reviewer,

I want to express my entire gratitude for your effort to read and useful comment my review.

I went through the whole article and corrected the sentences and expressions taking into account your suggestions.

I will present them in detail in the following below.

1. In the review entitled “REVISITING TETRA-p-SULPHONATED PORPHYRIN AS ANTIMICROBIAL PHOTODYNAMIC THERAPY AGENT,” the author describes not only the research area of the given title but also broad topics on antimicrobial photodynamic therapy - from the history of sunbathing healthcare in the ancient China, India, Egypt, or Greece to the future application of photodynamic therapy for a new COVID-19 treatment.

Thank you for your appreciation.

2. It seems that the author pays too much attention to trifling details and misses the big picture. Overall, the manuscript is very rambling and difficult to follow. The topic is interesting but the manuscript does not communicate it well. Therefore, the author should rewrite the manuscript to concentrate on the main point of the discussion.

I rearranged the whole paper text to make it clearer. I inserted new paragraphs or removed some vague or insignificant phrases. I also tried to emphasize the main aspect of this review: the use of positively charged double-charged sulfonated porphyrin as a photodynamic agent (including photophysical properties, photodynamic mechanisms, absorption/emission quenching, photodynamic activity on HSV-1) to eradicate SARS-CoV-2 (COVID-19) on surfaces.

I wish that this version of the work meets the requirements of the reviewer.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I find the revision improved in comparison with original submission. Therefore, I would recommend its publication, if the following issue is addressed by the author.

1) How many valence electrons does carbon have? 4 or 5? Recheck the structures of porphyrins in Figure 5.

Author Response

Dear Reviewer,

Thank you for your last suggestions to improve my paper quality.

Yes, indeed there are some mistakes in the carbon valence from Figure 5.

I redraw this figure checking the carbon's valences.

Thanks again.

Kind regards

R.Ion

Author Response File: Author Response.pdf