A Hydroalcoholic Gel-Based Disinfection System for Deteriogenic Fungi on the Contemporary Mixed Media Artwork Poesia by Alessandro Kokocinski

Round 1

Reviewer 1 Report

The article “A hydroalcoholic gel-based disinfection system for deteriogenic fungi on the contemporary mixed media artwork Poesia by Alessandro Kokocinski” presents the use of a new alcoholic hydrogel for the disinfection and removal of induced chromatic alterations in heritage materials. The effectiveness of the hydrogel was tested on a replication of a multimaterial collage by artist Alessandro Kokocinski, which was first characterized using various diagnostic and laboratory techniques. Results showed the hydrogel to be successful in removing and inhibiting fungal proliferation, as well as mitigating color changes caused by fungi, and could therefore potentially be applied more extensively to cultural heritage. The article is interesting and I believe the analytical approach is appropriate for the study of the artwork object of this work. However, there are some parts that in my opinion could use some improvement.

The abstract is concise and contains the information needed to describe the main findings. Please check the following sentence “pyrolysis coupled with gas-chromatography, and mass spectrometry” the way it is worked makes it look like these are two separate techniques instead of being a single, hyphenated technique.

Figure 1: it would be useful to see a color chart under the before and after pictures to better appreciate the differences.

Lines 123-124 “Moreover, pH measurements were carried out, to define the initial conservation status of the artwork and to monitor the effects of the cleaning and disinfection treatments” can the authors explain what to they mean with “define the initial conservation status of the artwork”?

Lines 190-198: I'm not a biologist, but I'm puzzled by the authors' decision to crush fungal biomasses. The control appears to only be made up of crushed mycelium and saline solution, with no fungal growth seen in Figure 8. What is the explanation for this?

Line 225 “vinyl polyacetate” please change it to “poly(vinyl acetate)” or “polyvinyl acetate”

Lines 244-249: I find this part confusing; can you explain the final concentration of spores/ml of the used suspension?

Lines 272-273 “Different blue pigments could give such a response, i.e., ultramarine blue, indigo, and cobalt blue” do you have a reference for this interesting information?

Lines 280-282 I find this part confusing, can you please rephrase it in a clearer way?

Lines 292-293 “When the IRFC response, the most probable pigments are artificial ultramarine blue and indigo” what do you mean with “when”?

From line 300 on, I have a couple of remarks on FTIR analysis discussion:

the paper does not provide any references to support the attribution of the FTIR absorptions detected in the polyesters, cellulose, or calcium carbonate. The signals are not analyzed in detail and this section may be more suitable for an internal report rather than a peer-reviewed publication.

Additionally, it appears that the absorptions marked in Figure 6 and subsequent figures are not discussed in detail in the text or presented in any tables. Some of these absorptions (such as 2514, 2239, 2142, and 2042 cm^-1 in Figure 6) may be spectral artifacts that are a result of the DRIFTS methodology chosen for analysis. In my experience, DRIFTS can sometimes be more difficult to interpret compared to other FTIR methods like transmission or ATR.

I think adding some arrows to indicate the fungal hyphae in Figure 9 would make a great addition to the paper. I understand that in the after treatment (B in figure 9) there are still some hyphae visible. Why didn’t’ the authors perform another swab sampling on the artwork after the treatment with the gels to verify the biocidal effect? Did the authors consider the possibility of verifying the biocidal effects of the gel through microbiological culture and/or ATP quantification?

Without any further analysis proving the fungicidal effects of the alcohols used in this study, is there any way to establish that the effect of the gels is indeed fungicidal and not just fungistatic?

Why did the authors decide to use only ethyl alcohol instead of a combination of alcohol and a biocide soluble in it (such as ortho phenylphenol for instance). In the introduction that authors state that “For the conservation of contemporary art, the alcoholic hydrogel studied here, proved to be a valid tool in cases where the polymeric composition of the artifacts makes it difficult to apply traditional chemical biocides, either for the risk of interference with some of the constituent components, or when the degradation of the artwork is in a very advanced state. Utilized in this case for the conservation of a mixed media collage, it is suitable for the restoration of different types of water-sensitive works of art” is there any published reference that list the drawbacks of using biocides soluble in alcohol with materials similar to the ones studied here?

I would argue that the effect of the hydrogels without alcohol should have been tested too to investigate the possible effect of the blank gels on the fungal colonization.

Finally, please check the numbering of the figures in the text.

Author Response

Dear Reviewer,

first of all, on behalf of all the authors, I would like to thank you for the careful revision work, for the positive comment to the paper, and for the suggestions aimed at improving the manuscript.

We made corrections, as requested, and also a further English revision.

In fact, this was performed in the previous step of submission by one of the author (Elisabeth Wicks) that is a native English speaker. Anyway, she made a further deep revision. We hope that now the English language is ok.

The replies to your comments, are supplied point by point in the attached file.

Thank you again, 

Sincerely, Claudia Pelosi (Corresponding author) 

Author Response File: Author Response.pdf

Reviewer 2 Report

I read your manuscript with considerable interest. The subject is vital, the manuscript is well-written, and the structure is sound. I only have some methodological and technological concerns:

- Why did the authors opt for the wet methods for microbial disinfection compared to physical treatment (UV, Plasma and electric discharge...)? 

- How many times can your method be applied to the same artistic fabric? 

- Did the authors test the microbial regrowth after inactivation? What if the infecting microorganism has a resistance form (spores)? Will your prepared gel disinfect them as well? 

- As alcohols can react with Ti, Fe and especially Ca, how are authors sure that the application of your method will not alter the atomic/molecular composition of the artistic sample?

- A synthetic figure in the discussion section should be added to illustrate the microbial inactivation mechanism. 

Author Response

Dear Reviewer,

first of all, on behalf of all the authors, I would like to thank you for the careful revision work, for the positive comment to the paper, and for the suggestions aimed at improving the manuscript.

We made corrections, as requested, and also a further English revision.

In fact, this was performed in the previous step of submission by one of the author (Elisabeth Wicks) that is a native English speaker. Anyway, she made a further deep revision. We hope that now the English language is ok.

The replies to your comments, are supplied point by point in the attached file.

Thank you again, 

Sincerely, Claudia Pelosi (Corresponding author)

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Congratulations to the authors for this nice work. I really enjoyed reading it.