Doxorubicin-Loaded Silica Nanocomposites for Cancer Treatment

Round 1

Reviewer 1 Report

In this manuscript, Popova et al, addressed the “Doxorubicin-loaded silica nanocomposites for cancer treatment”. Having examined the manuscript, I note that though it discusses some interesting observations, to be considered for MDPI Coatings, the following are some of the comments that the authors might find useful for future submission. This manuscript is addressing the importance of  nylon coated silica nanoparticle drug delivery systems for doxorubicin for effective anticancer treatment. This type of manuscript is extremely valuable at the community and global level.

General comments

1.     The title is appropriately captured and manuscript is well written.

2.     It would be more interesting if the authors performed in vivo safety and anti-cancer efficacy studies

Author Response

Thank you for the valuable suggestions and comments. We have carefully examined the comments and suggestions and revised the manuscript accordingly. We presented the word file with track changes. Please find as follows the responses to the comments. Please note that all the comments are bold-faced, and the authors' reply follows immediately below the comments.

It would be more interesting if the authors performed in vivo safety and anti-cancer efficacy studies.

Thank you for your suggestion. It will be the next step of our work. However, in this paper we have focused on chemical part, physical characterization, and first biocompatibility experiment.

Reviewer 2 Report

The experimental procedures were well designed and conducted. Some comments for the authors follow.

item 2.2. insert the samples that were analyzed DOX/SiNPs and DOX/SiNPs-Nylon

 

it would be interesting to show whether the coating influences the stability of the formulation. Detail in item 2.5 the time used in carrying out the experiment and the criterion for classifying the nanoparticles as stable or unstable.

Author Response

Thank you for the valuable suggestions and comments. We have carefully examined the comments and suggestions and revised the manuscript accordingly. We presented the word file with track changes. Please find as follows the responses to the comments. Please note that all the comments are bold-faced, and the authors' reply follows immediately below the comments.

item 2.2. insert the samples that were analyzed DOX/SiNPs and DOX/SiNPs-Nylon

We have inserted some text. See section 2.2.

it would be interesting to show whether the coating influences the stability of the formulation.

Thank you for your comments. The SiNPs-Nylon stable in aquous for a half of the year. We have added some comments in Section 3.2.

Detail in item 2.5 the time used in carrying out the experiment and the criterion for classifying the nanoparticles as stable or unstable.

Thank you for your comments. We have added some stability criteria in Section 2.5.

Reviewer 3 Report

In this study, Popova et al. developed doxorubicin (DOX)-loaded silica nanoparticles (SiNPs) and SiNPs-Nylon nanocomposites for cancer treatment. They characterized SiNP nanocomposites via TEM, DLS analysis, and stability tests. Then, they investigated the release kinetics and cytotoxicity of DOX-loaded SiNP nanocomposites. This work demonstrates the capacity of SiNPs as a DOX nanocarrier and shows their potential as a cancer therapeutics, but there are several issues that should be addressed before publication as noted below.

Major issues

Zeta-potential measurement can imply changes in the surface status of SiNPs so it is crucial evidence for demonstrating the surface modification of SiNPs. It is suggested to include zeta-potential measurement after introducing Nylon and DOX to SiNPs.

Please specify the sample size for in vitro release tests and cell viability assay in the captions of Figures 5-7. Also, statistical analyses should be done to identify the significance of changes.

SiNPs-DOX has lower IC50 than SiNPs-Nylon-DOX and it does not seem that Nylon modification improves the function of nanocomposites. Nylon may improve the drug loading capacity but IC50 is more important to reduce the dose of DOX and the subsequent side effects. Please discuss the rationale for using Nylon.

Minor issues

In Figure 5C and 5D, SiNPs and SiNPs-Nylon show different sensitivity to temperature changes. Please discuss the reason why the release kinetics of SiNPs-Nylon is not significantly affected by temperature.

SiNPs and SiNPs-Nylon reduce the cell viability at the doses higher than 11 μg/ml, which is unusual for other silica nanoparticles. Please discuss the reason.

In Figures 5-7, x-and y- axes should have ticks.

In cell viability tests, it is mentioned that PBS was used for the control groups. It is not clear whether the authors used pure PBS, which is not proper for cell culture for 48 h, or a PBS-added medium. Please clearly state it.

There are some typos that can be confusing. For example, Figure 2 in Table 1 should be corrected to Figure 1 and cell viliabilility in Figure 6 should be corrected.

 

 

Author Response

Thank you for the valuable suggestions and comments. We have carefully examined the comments and suggestions and revised the manuscript accordingly. We presented the word file with track changes. Please find as follows the responses to the comments. Please note that all the comments are bold-faced, and the authors' reply follows immediately below the comments.

Zeta-potential measurement can imply changes in the surface status of SiNPs so it is crucial evidence for demonstrating the surface modification of SiNPs. It is suggested to include zeta-potential measurement after introducing Nylon and DOX to SiNPs.

Thank you for your suggestion. We have inserted zeta-potential in Table 1 and inserted in section 3.3. after Dox loading.

Please specify the sample size for in vitro release tests and cell viability assay in the captions of Figures 5-7. Also, statistical analyses should be done to identify the significance of changes.

We have added the data in figures caption. In Figures 5-7 the data presented with errors showing the possible differences between values.

SiNPs-DOX has lower IC50 than SiNPs-Nylon-DOX and it does not seem that Nylon modification improves the function of nanocomposites. Nylon may improve the drug loading capacity but IC50 is more important to reduce the dose of DOX and the subsequent side effects. Please discuss the rationale for using Nylon.

SiNPs-DOX and SiNPs-Nylon-DOX has almost the same per DOX concentration (Table 4). It means that for this experiment we take different amounts of nanoparticles. Per NPs, the SiNPs-Nylon-DOX has lower IC50 value due to the higher Dox-loading capacity. For patient treatment, the drug concentration construction usually presented in µg/mL. In this way, Nylon coating provide higher drug-loading and more essential anticancer properties. Moreover, according to Figure 5, SiNPs-Nylon-DOX is more stable at pH 7.4, which means low drug release in human plasma. The pH lowering in cancer cells will lead to the drug release in cancer treatment. For SiNPs-DOX, some of the drug will release in plasma lead to the toxicity.

In Figure 5C and 5D, SiNPs and SiNPs-Nylon show different sensitivity to temperature changes. Please discuss the reason why the release kinetics of SiNPs-Nylon is not significantly affected by temperature.

Thank you for your suggestion. We have added some discussion in Section 3.4.

SiNPs and SiNPs-Nylon reduce the cell viability at the doses higher than 11 μg/ml, which is unusual for other silica nanoparticles. Please discuss the reason.

Thank you for your suggestion. We have high drug-loading capacity. In this way, we have low IC50 values.

In Figures 5-7, x-and y- axes should have ticks.

Thank you for your comments. We have revised the figures.

In cell viability tests, it is mentioned that PBS was used for the control groups. It is not clear whether the authors used pure PBS, which is not proper for cell culture for 48 h, or a PBS-added medium. Please clearly state it.

Thank you for your comments. We have added the information in Figure caption and experimental part.

There are some typos that can be confusing. For example, Figure 2 in Table 1 should be corrected to Figure 1 and cell viliabilility in Figure 6 should be corrected.

Thank you for your comments. We have done the text corrections.

Reviewer 4 Report

I would like to recommend this manuscript for publication after minor revision:

 

1.     When all abbreviations in the text appear for the first time, the full name shall be marked in front.

2.     Figure 1, why are the scalebars of the control samples in the figure different and very random, because the multiple of the control images are different? It is recommended to unify the image multiples as much as possible.

3.     Figure 5-7, the legend should be modified with (mean±SD, N=?)

4.     For the cell experiment, a fluorescent characterization is suggested as the reference perform < Ru Xu, Kun Zhang, Jiaheng Liang, Feng Gao, Jingan Li, Fangxia Guan. Hyaluronic acid/polyethyleneimine nanoparticles loaded with copper ion and disulfiram for esophageal cancer. Carbohydrate Polymers 2021; 261: 117846.>.

5.     For the Introduction, it is suggested to briefly introduce the potential effect of this nanoparticles on colorectal cancer < Xiaojing Sun, Zhonghua Xue, Aqeela Yasin, Yingkun He, Yaru Chai, Jingan Li, Kun Zhang, Colorectal Cancer and Adjacent Normal Mucosa Differ in Apoptotic and Inflammatory Protein Expression, Engineered Regeneration 2 (2022) 279-287.>.

Author Response

Thank you for the valuable suggestions and comments. We have carefully examined the comments and suggestions and revised the manuscript accordingly. We presented the word file with track changes. Please find as follows the responses to the comments. Please note that all the comments are bold-faced, and the authors' reply follows immediately below the comments.

When all abbreviations in the text appear for the first time, the full name shall be marked in front.

Thank you for your comments. We have done the text corrections.

Figure 1, why are the scalebars of the control samples in the figure different and very random, because the multiple of the control images are different? It is recommended to unify the image multiples as much as possible.

Thank you for your comments. We have revised Figure 1.

Figure 5-7, the legend should be modified with (mean±SD, N=?)

Thank you for your comments. We have revised Figure caption.

For the cell experiment, a fluorescent characterization is suggested as the reference perform < Ru Xu, Kun Zhang, Jiaheng Liang, Feng Gao, Jingan Li, Fangxia Guan. Hyaluronic acid/polyethyleneimine nanoparticles loaded with copper ion and disulfiram for esophageal cancer. Carbohydrate Polymers 2021; 261: 117846.>.

Thank you for your suggestion. According to the work above, for such fluorescence characterization, we should modify our nanoparticles with fluorescence dye. We haven’t done it yet. It will be the next step of our work for an extensive cell experiment.  

For the Introduction, it is suggested to briefly introduce the potential effect of this nanoparticles on colorectal cancer < Xiaojing Sun, Zhonghua Xue, Aqeela Yasin, Yingkun He, Yaru Chai, Jingan Li, Kun Zhang, Colorectal Cancer and Adjacent Normal Mucosa Differ in Apoptotic and Inflammatory Protein Expression, Engineered Regeneration 2 (2022) 279-287.>.

Thank you for your suggestion. We have revised the Introduction section.