Review Reports

Round 1

Reviewer 1 Report

·         In the abstract, the characterizations and the results obtained should be given rather than general information.

·         The number of replications of drug release experiments should be mentioned, and SD values ​​should be given.

·         “At acidic pH, both PDA NPs and gentamicin are positively charged because of the protonation of amine groups. Thereby, gentamicin molecules easily escape from PDA because of the repulsive forces.”, “the release mechanism of G-PDA NPs is also influenced by the structural behavior of the PDA at different pH conditions.” Scheme-1 can be drawn for similar explanation sentences. Giving the molecular behavior at different pHs using formulas will make the study more remarkable.

·         169h or 168h? Both are used in the text.

·         Figure S2. , Figure S3, Figure S4. It should be mentioned that the images are the result of which analysis and what they are made for.

·         The sentence should be changed to: "Figures 4A, 5A and 6A show the fitting of drug release data at pH 7.4, 5, and 3, respectively, in the Ritger-Peppas and Higuchi model."

·         An expression such as “As shown in the Figure S2, Figure S3, Figure S4” can be added to the sentence mentioned in Figure S2, Figure S3, and Figure S4 in the manuscript.

·         The conclusion part can be shortened. The results obtained should be given by emphasizing the importance of the study.

 

·         The names of the x-axes of the graphs in Figure 4B, Figure 5B, and Figure 6B must be the same.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The article studies the drug loading and release behavior using the antibiotic gentamicin as a model drug into polydopamine nanoparticles (PDA NPs). The manuscript is very well presented, written and explains in details the drug release system. All the data presented supported the hypothesis that the PDA NPs are stable and can release the gentamicine at lower pHs mainly due to electrostatic interactions between the system compounds. I recommend the paper publication after the asnwer of some questions pointed:

- I do not know if it is due to a Journal style, but the lines 91-97 should be placed in the Conclusions, in my opinion.

- Biologically, these release systems are indeed relevant? I ask it because they need a abrupt decrease in pH by the bacterial infection to release the drug content, which can not be achieve in a in vivo approach. Also, as the first hours of release, it is expected that the antibiotic acts against the bacteria, which consequently can slow down the pH decrease. I'd like to know the authors' comments.

- A drug delivery system can be driven, at the same time, by two kinetic models? Even though they are well-fitted, it should be interesting to choose one of them.

Minor points:

Line 12 - "reactive in nature, acquired..."

Line 111 - 1 M

Line 113 - 3,500

Line 116 and 252 - verify excess of spaces before "MilliQ water" and "These models"

Line 126 - homogenize "gentamicine" not "Gentamicine"

Line 127 - "which was well.."

Line 138 - "PBS (0.1 M)"

Author Response

Please see the attachment

Author Response File: Author Response.pdf