The Reversible Transformation of a Vesicular Aggregate in Response to a pH Oscillation

Round 1

Reviewer 1 Report

The research paper titled "Reversible Transformation of a Vesicular Aggregate in Response to pH Oscillation" by Shimada and colleagues highlights the pH oscillation response of vesicular aggregates. While the study is commendable and exhibits moderate novelty in the reported research, I have identified several areas for improvement to enhance the overall quality and address specific scientific concerns.

1.     The introduction should explicitly state the novelty of the work. Authors are encouraged to clearly articulate the unique contributions of their research.

2.     On page 2 of 13, Figure 1 presents an issue where the scale of the image is located outside the image, deviating from conventional presentation standards. It is recommended to place scale values inside the image for all figures, including bright field and confocal images.

3.     The manuscript should address the observed polydispersity in vesicle sizes, as evident in Figure 1. Authors should acknowledge and discuss this aspect, providing context by referring to similar systems investigated in previous studies.

4.     The first line of the abstract, "The transformation of amphiphilic molecular assemblies in response to chemical oscillations is fundamental in biological systems," requires further clarification and additional citations to support the statement.

5.     To strengthen the study, the authors are encouraged to conduct additional morphology studies using techniques such as TEM, SEM, and AFM. Including data from dynamic light scattering and electrophoretic light scattering measurements for size and zeta-potential would provide valuable insights into the vesicles' characteristics.

6.     Discussion of the manuscript is short and incomplete; author should elaborate the discussion and can compare it with previous studies/research with similar systems.

Author Response

Thank you for the review. Please see the attachement.

Author Response File: Author Response.pdf

Reviewer 2 Report

This manuscript describes pH-dependent changes of DDMABr vesicles where the pH-changes are triggered by a chemical oscillation. This is a fundamentally interesting question but also of ample importance for the understanding of biological systems. The authors used for their investigations the bromate-sulfite system and did their investigations in pure water but also in phosphate buffer, where they observed substantially different behaviour. The investigations are described very clearly and the authors did work very carefully by addressing well the potential pitfalls in doing such rather complex experiments. However, there still remain a number of open questions that should be addressed in a revision of this manuscript.

The most important one is the fact that it is never explained where the pH-dependence of the systems comes from. The DDMABr as vesicle forming surfactant should be inert to pH effects, so where do the changes as a function of pH come from? Here definitely a good explanation is required.

In Fig. 2b it is unclear to me why one does not see the effect of adding Nasulfite after 1000-1200 s? Or are these plots not directly related to the ones shown in Fig. 2a?

To Fig. 4a it should be explained where the substantial darkening of the aggregates seen for longer times for 0.5 M come from.

For Fig. 6 it should be clarified what t = 0 s means. According to Fig. 5a for the first 100 s nothing should happen but here one sees substantial changes for shorter times that should be before the addition of Nasulfite.

Apart from these comments that should become clarified within a revision of the manuscript, I think that this manuscript deserves publication.

Author Response

Thank you for the review. Please see the attachement.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Authors have significantly improved the manuscript, so recommend to publish in this journal. However, it would be good for the readers if authors include one sction of the conclusions of the study.