Innovative Skin Product O/W Emulsions Containing Lignin, Multiwall Carbon Nanotubes and Graphene Oxide Nanoadditives with Enhanced Sun Protection Factor and UV Stability Properties

Round 1

Reviewer 1 Report

It is recommended that the authors provide more details regarding the statistical analyses of their results, and support their results to show if the changes in SPF, viscosity or stability factors are statistically significant.

In terms of study design, it is recommended that the authors provide more description of the effects of used nanoadditives on appearance and consumers acceptance criteria of a nanocosmetics preparation, either include it in the design of the study or provide more comprehensive discussion in the manuscript.

Improvement of writing, with a focus on grammatical errors is recommended. There are also minor spell-checks required, for example:

• page 2 line 43 the correct word for 'comerical' seems to be 'commercial'
• page 2 line 64 'containg' should be corrected
• page 3 line 95, the following sentence needs modification 'Moreover, many articles in the literature confirm the use of MWCNTs are excellent UV filters'
• page 3 line 110, do authors mean 'stearic acid' by 'steatic acid' or it is correct in the current format of writing?
• page 4 line 137 'nto'
• page 5 line 146 '5×10-3 mg/mL'

Author Response

We would like to thank the reviewer for his time and fair comments.

Author Response File: Author Response.docx

Reviewer 2 Report

This report “applnano-1519521” entitled “Innovative Skin Product O/W Emulsions Containing Lignin, Multiwall Carbon Nanotubes, and Graphene Oxide Nanoadditives with Enhanced SPF and UV Stability Properties” is by Nikolaos Nikolaidis and group. This report is interesting and written well. It is clear and state forward. This report has the potential to contribute significantly to the literature and industrial development. I recommend this report after minor revision.

Specific comments:

• In title, state full form of SPF
• Abstract, summed up in one paragraph, includes biocompatibility results and state future implications
• Line 60; space before as, “tubes (MWCNTs)as”
• Line 63-64; provide the reference
• 2. Preparation of the Emulsions; if possible consider Kraft LGN combination with GO and MWCNTs.
• Perform biocompatibility assessment for the product prototypes.
• Suggest how to control the tone if GO and CNTS are used, it must be a black color emulsion.
• Results and discussion; present this section with subsections, it will be easier to follow, readers of the journal would appreciate.
• Table 4. 72 h irradiation section is not visible.
• Conclusions; revise this section, conclude results for lignin combination with GO and MWCNTs, mention future implications.

Author Response

We would like to thank the reviewer for his time and fair comments.

Author Response File: Author Response.docx

Reviewer 3 Report

This is a study about O/W emulsions containing lignin, multiwall carbon nanotubes and graphene oxide nanoadditives with enhanced SPF and UV stability properties. It could be interesting for the readership of applied nano. However, the following issues should be addressed before it can be considerred for the publication.

1. There are so many compositions in this emulsion. The author should add one scheme to show the structure of the emulsion.
2. Several recent studies (doi.org/10.1016/j.actbio.2020.08.042; doi.org/10.1016/j.colsurfb.2021.111604; doi.org/10.1021/acs.biomac.1c00581) related to different methods for preparation of stable emulsions are encouraged to be included in the introduction.
3. What is the size of the emulsion? Some DLS or TEM results need to be shown.
4. The mechanism for the stability of the emulsion has to be discussed in details.

Author Response

We would like to thank the reviewer for his time and fair comments.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

accept