Preparation of Nanoparticle-Loaded Microbubbles via an Electrohydrodynamic Atomization Process

Round 1

Reviewer 1 Report

Title: “Preparation of Nanoparticle Loaded Microbubbles via Electrohydrodynamic Atomization Process”

In this research article, the authors have reported the one-step preparation of nanoparticle loaded microbubbles by coaxial electrohydrodynamic atomization technology for the first time. The authors used Bovine serum protein (BSA) as the model material of bubble shell layer to study the effect of the loading of nanoparticles on the stability of microbubbles. The results indicated that the concentration of nanoparticles has a significant impact on the stability of microbubbles, and only loading a proper amount of nanoparticles is useful to improve the stability of microbubbles. The authors showed the size distributions of microbubbles at different gas/liquid flow rates. The results also showed that nanoparticle loaded microbubbles with size distribution in the range of 120-200 μm can be prepared under the optimal conditions. The authors have given concise introduction about the microbubbles. The authors also explained the conventional methods for the preparation of microbubbles. The morphology and size of microbubbles at different time points were observed by optical microscope with real-time photography function. Various photos were taken with the microscope and Nano Measurer software was used to analyze the size of microbubbles from the taken photos. Overall, the manuscript was well written, and all the references are in proper format. This research article can be published in “Applied Sciences” without any revision. Page 3, line 97: Please replace “hell layer” with “shell layer”.

Author Response

This research article can be published in “Applied Sciences” without any revision. Page 3, line 97: Please replace “hell layer” with “shell layer”.

Response: The authors would like to thank the reviewer for the good comments and careful reading. The typo “hell layer” has been corrected as “shell layer”.

Reviewer 2 Report

Title: Preparation of Nanoparticle Loaded Microbubbles via Electrohydrodynamic Atomization Process

Author: Xin-Bin Nie, Yong Wang, Xiong Ran, Ji-Chuan Wu, Ran Wei, Wei-Cheng Yan

Manuscript ID: applsci-1654749

Recommendation: Publish after minor revisions

Comment: The manuscript by Nie et al. uses the electrohydrodynamic atomization method to prepare SiO₂-loaded microbubbles. The authors found that the stability of the nanoparticle-loaded microbubbles was improved. The stability improvement depends on the concentration of nanoparticles and spray process conditions (e.g., voltage). It is to the authors credit to first report the nanoparticle-microbubble complexes by electrohydrodynamic atomization method, thus this can be published in applied science. Nonetheless, a few comments listed below need to be addressed:

1. Will high electric filed affect the stability of SiO₂ nanoparticles (i.e., shape)? This can be tested by running a negative control without producing any microbubbles.

2. Page 3, Line 127, change to “Figures 2-3 show …”

3. In Figure 2, I guess the red circles are for indicating the merge of microbubbles phenomena. However, I would think red arrows pointing from neighbor small bubble to the merged centered bubble will be clearer to indicate an Oswald ripening process.

4. In Figure 3, first, it seems that, with the SiO₂ NPs encapsulated, the microbubbles size becomes non-uniform, compare to the one shown in Figure 2. Why is this?;

Second and the most important, there is a lack of strong evidence proving the presence of SiO2 nanoparticles inside the microbubbles.

Third, what is the nanoparticle encapsulation efficiency in the bubble? What is the fraction of nanoparticles freed in the suspension?

5. Figure 4 is missing error bar and a longer time maybe referred as the difference of N/N0 was small in 15 min.

6. Page 7, Line 187, it is generally accepted that the charge on the surface will make the bubble more stable due to the repulsion force. The author should make this point clear in related sentences. See references: Nano Lett. 2022, 22, 612−621; and Angew. Chem. Int. Ed. 2022, 61, e202112995.

7. Can the authors map the distribution of nanoparticles inside the microbubbles? Since the core is full of gas, and I may guess that the solid SiO₂ sticks near the inner BSA shell layer, which stabilizes the shell structure and lowers the surface tension.

8. The take home message from Figure 7 is unclear. Should the readers care the initial size of the microbubbles (at time 0) as a function of particle concentration or the time-dependent size changes? Those detailed messages should be included in the caption.

9. Page 8, Lines 226-229, the sentence is repeating experimental observations (i.e., enhanced stability or lowered interfacial tension) without explaining the exact underlying mechanism, thus losing connection to the conclusion draw from previous sentences (same page, Lines 217-219). The logic flow should be simple: as encapsulating the nanoparticles, the size of the microbubbles increased, and this reduces the surface tension according to the classical Laplace equation.

Comments for author File: Comments.docx

Author Response

Please see the attachment

Author Response File: Author Response.docx

Reviewer 3 Report

Review for

The level of originality of the paper is high. The literature review and proposed methodology are properly discussed and compared to the previous studies.

In this paper, authors used 37 sources, containing both historical and fundamental works, as well as the latest scientific research on this topic. But the literature review can be structured. The papers discussed many points of this study. Please, discuss these papers.

TRIPLE BOTTOM LINE AND CORPORATE SOCIAL RESPONSIBILITY PERFORMANCE INDICATORS FOR RUSSIAN COMPANIESWEB OF SCIENCE

Authors:  Varyash, Igor; Mikhaylov, Alexey; Moiseev, Nikita; Aleshin, Kirill

Published:Sep 2020 in Entrepreneurship and Sustainability Issues

DOI: 10.9770/JESI.2020.8.1(22)

INVESTIGATING THE RELATION OF GDP PER CAPITA AND CORRUPTION INDEXWEB OF SCIENCE

Authors:  Moiseev, Nikita; Mikhaylov, Alexey; Varyash, Igor; Saqib, Abdul

Published:Sep 2020 in Entrepreneurship and Sustainability Issues

DOI: 10.9770/JESI.2020.8.1(52)

The introduction section has benefit from having a clearer structure of what to expect in the paper. Furthermore, the author(s) would benefit from being more concise in their writing, as much of the content was redundant and overemphasized. While it is good practice to assume the reader has no prior knowledge of the content, a topic and/or discussion does not need to be explained over and over again if it is stated both adequately and appropriately once.

Some conclusions contribute to the study of the problem. The author does not formulate the problem itself – it makes impossible to analyse the contribution of the paper. The aim or the question of the paper (or even the hypothesis of the author) are formulated.

Overall, it is very clear to grasp understanding of the manuscript and content in its current state. I strongly advise using hypothesis points to articulate and/or express material in scientific writing. Publication of this piece seems likely in any reputable scientific periodical after a correction in the writing of the manuscript.

Table 1. is important to explore the specifics. Some conclusions can contribute to the study of the problem.

Authors need to add more details on the range of simulation considered in this work should be clearly outlined within the abstract. The current statements are vague and too general to get an idea of the work that have been accomplished.

The paper possesses a proper form of well-structured and readable technical language of the field and represents the expected knowledge of the journal`s readership.

There are minor errors in English, but this does not affect the general nature of the work. The current study brings many new to the existing literature or field. For one, the author(s) seem to have a good grasp of the current literature on their topic area (i.e., recent literature and seminal texts relevant to their study is not cited/referenced).

Author Response

We thank the reviewer for the comments. We have carefully read the comments and we think the reviewer may attached the wrong comments. The comments seem to be not applicable to this work, for instance, the reviewer ask for adding the following references in the introduction section which are totally not related to the present study:

1. TRIPLE BOTTOM LINE AND CORPORATE SOCIAL RESPONSIBILITY PERFORMANCE INDICATORS FOR RUSSIAN COMPANIESWEB OF SCIENCE

Authors:  Varyash, Igor; Mikhaylov, Alexey; Moiseev, Nikita; Aleshin, Kirill

Published:Sep 2020 in Entrepreneurship and Sustainability Issues

DOI: 10.9770/JESI.2020.8.1(22)

2. INVESTIGATING THE RELATION OF GDP PER CAPITA AND CORRUPTION INDEXWEB OF SCIENCE

Authors:  Moiseev, Nikita; Mikhaylov, Alexey; Varyash, Igor; Saqib, Abdul

Published:Sep 2020 in Entrepreneurship and Sustainability Issues

DOI: 10.9770/JESI.2020.8.1(52)