Fabrication of PVTF/COL Composite Films and Its Impact on Osteogenic Differentiation
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis paper presents a work on the preparation of, Poly (vinylidene fluoride trifluoro ethylene) PVTF/(collagen)COL composite films by using adhesive polydopamine (PDA), which is known for its excellent biocompatibility and wet adhesion properties. It is known that Polyvinylidene fluoride (PVDF) is an electroactive material and known for its excellent piezoelectricity and biocompatibility property. Also, in bones, collagen is the most prevalent, constituting over 90% of the organic mass, primarily secreted by osteoblasts.
The aim of This study is to present a novel and effective approach for surface modification of PVTF and explores its potential applications in Guided Bone Regeneration, GBR. Here, it was found that collagen modification shifted the surface potential of PVTF to a positive value, which enhanced hydrophilicity, and preserved the piezoelectric and mechanical properties of PVTF. On the other hand, it was observed that the bioactivity of the composite films was significantly improved, while promoting adhesion, proliferation, and osteogenic differentiation of bone marrow-derived stem cells (BMSCs) on it.
It is also known that Periodontitis is an infection and inflammation caused by anaerobic bacterial colonies in the oral environment, which can damage the gum and tooth-supporting tissues. The ideal treatment for periodontitis involves reconstructing the complex structure of periodontal tissue, including dental bone, alveolar bone, periodontal ligaments, and gingival tissue.
So that, here the surface topography and average roughness of the composite films were studied by field-emission scanning electron microscope and atomic force microscope in tapping mode respectively. Tensile and puncture strength of films were tested using the Universal Testing Machine. Bone marrow mesenchymal stem cells were isolated from the tibiae of three-week-old male Sprague-Dawley rats.
According to the above summary, I like this work, which gave highly important results with nice pictures, and with qualitative explanation. However, here one expects some quantitative parameters, for example in Figure 6.a the strain-stress curve must be used to produce the shear modulus for different films, and then results has to be used to explained why the different parameters were produced, for the different films.
Author Response
Comments 1：However, here one expects some quantitative parameters, for example in Figure 6.a the strain-stress curve must be used to produce the shear modulus for different films, and then results has to be used to explained why the different parameters were produced, for the different films.
Response 1：Thank you very much for the comments. By using the stress-strain curve in Figure 6.a, we calculated the tensile strength of the composite film and conducted relevant comparisons and analyses in the manuscript. Due to the application site being the alveolar bone, this study mainly focuses on mechanical properties that are more representative of the application, such as tensile strength and puncture strength. In contrast, the representativeness of shear modulus is not as strong.
Reviewer 2 Report
Comments and Suggestions for AuthorsI reviewed your manuscripts carefully and felt yours presented solid experimental work and valuable results in the field. However, some careful revisions seem to be needed to improve clarity and highlight novelty, and you should polish the manuscript's language and figures. Concretely speaking, I would like you to revise the following points.
#1; Introduction part:
#1-1: Please elaborate more clearly on what is novel in this study compared to previous PVTF or collagen-based GBR membrane studies.
#1-2: Please add the table or bullet-point comparison of your composite vs. previously reported GBR membranes.
#2: Materials and Methods: #2-1: Please clarify how the polarization strength (D33 = 20) was determined and standardized for all samples. Also, explain how this value relates to other reported values in the literature.
#2-2: In section 2.2, describe more clearly how the collagen concentration was selected (1, 2, and 3 mg/mL). Is there a rationale based on physiological relevance or previous GBR membrane studies?
#3; Results and Discussion:
#3-1: Please clarify and emphasize the comparative mechanical strength data in section 3.3. While the authors rightly compare tensile and puncture strength with commercial products, a more precise conclusion on whether the proposed composite can outperform existing membranes in clinical handling would be helpful.
#3-2: In section 3.4, the ALP results are promising. However, adding a figure comparing ALP activity statistically across groups (including control) could strengthen the discussion.
#3-3: The debate on collagen’s impact on bioactivity is comprehensive. Still, it would be beneficial to include a sentence acknowledging that collagen degradation in vivo could affect long-term performance and whether any biodegradation testing was considered or planned.
#4; Figures and Tables:
#4-1: Please improve the resolution and labeling of Figures 2, 3, 5, and 6. Some figure parts are not distinguishable, and axis labels could be enlarged for better readability.
#4-2: Consider adding a summary figure/table comparing mechanical, surface potential, and biocompatibility properties across PVTF, PP, and PPC1–3 to help readers grasp the material improvement at a glance.
#5; Language and Style:
The manuscript contains several grammatical and typographical errors (e.g., “et al.” misused, inconsistent verb tenses, run-on sentences). Please consider professional language editing or proofreading to improve clarity and readability.
#6: Conclusions
The conclusion would benefit from a more focused statement emphasizing the practical translational potential of PVTF/COL membranes in clinical GBR applications. Also, include one or two future perspectives (e.g., in vivo testing or long-term mechanical stability under physiological conditions).
Overall, the English is understandable, but improvements are required. Numerous grammatical issues, awkward phrasing, and inconsistencies in terminology may hinder reader comprehension. I recommend that the authors seek assistance from a native English speaker or use professional language editing services before publication.
Author Response
Thanks for sending us these comments. These comments are very helpful to improve this manuscript.
Comments 1-1：Please elaborate more clearly on what is novel in this study compared to previous PVTF or collagen-based GBR membrane studies.
Response 1-1：We have added some detailed instruction in the revised manuscript Line 55-64, Line 82-84 and Line 96-101.
Comments 1-2：Please add the table or bullet-point comparison of your composite vs. previously reported GBR membranes.
Response 1-2：We have added a bullet-point comparison table in the revised manuscript Line 95.
Comments 2-1：Please clarify how the polarization strength (D33 = 20) was determined and standardized for all samples. Also, explain how this value relates to other reported values in the literature.
Response 2-1：Previous studies has shown that polarized PVTF could promote osteogenic differentiation of stem cells, with the sample polarized to D33 = 15 exhibiting the best effect[Acta Biomaterialia 74 (2018) 291-301]. Since collagen has relatively weak piezoelectric properties, its inclusion in the composite may reduce the overall electrical properties. Therefore, in this study, PVTF was first polarized to D33 = 20 during the material processing stage. We have added it in the revised manuscript Line 120-124.
Comments 2-2：In section 2.2, describe more clearly how the collagen concentration was selected (1, 2, and 3 mg/mL). Is there a rationale based on physiological relevance or previous GBR membrane studies?
Response 2-2：When the concentration was higher than 3 mg/ml, the collagen solution becomes highly viscous, making it challenging to perform relevant experimental operations. Therefore, this study selected collagen solution with concentration of 1, 2, and 3 mg/ml for the following experiment. The relevant physiological or research-based rationale need further in-depth exploration.
Comments 3-1：Please clarify and emphasize the comparative mechanical strength data in section 3.3. While the authors rightly compare tensile and puncture strength with commercial products, a more precise conclusion on whether the proposed composite can outperform existing membranes in clinical handling would be helpful.
Response 3-1：The oral environment is extremely complex. And the specific gold standard for GBR application still requires further clinical research. Therefore, the comparison of mechanical strength results can indicate that the prepared membrane is sufficient to meet the common clinical application needs and has some advantages over collagen membranes. We have added this in the revised manuscript Line 333-342.
Comments 3-2：In section 3.4, the ALP results are promising. However, adding a figure comparing ALP activity statistically across groups (including control) could strengthen the discussion.
Response 3-2：In this study, BMSCs on film surface were first lysed using cell lysate. Then the total protein content and total ALP activity in the lysate were obtained using assay kits, detailed methods can be seen in Section 2.6. After calculation, the final unit ALP activity value was obtained, so there are no relevant staining images available.
Comments 3-3：The debate on collagen’s impact on bioactivity is comprehensive. Still, it would be beneficial to include a sentence acknowledging that collagen degradation in vivo could affect long-term performance and whether any biodegradation testing was considered or planned.
Response 3-3：We have added relevant discussion in the revised manuscript Line 375-379.
Comments 4-1：Please improve the resolution and labeling of Figures 2, 3, 5, and 6. Some figure parts are not distinguishable, and axis labels could be enlarged for better readability.
Response 4-1：We have adjusted the format of some figures and used clearer figures in the revised manuscript.
Comments 4-2：Consider adding a summary figure/table comparing mechanical, surface potential, and biocompatibility properties across PVTF, PP, and PPC1–3 to help readers grasp the material improvement at a glance.
Response 4-2：We have added a summary table in the manuscript Line 386.
Comments 5：Consider adding a summary figure/table comparing mechanical, surface potential, and biocompatibility properties across PVTF, PP, and PPC1–3 to help readers grasp the material improvement at a glance.
Response 5：We carefully checked and corrected possible grammar and formatting errors in the manuscript.
Comments 6：The conclusion would benefit from a more focused statement emphasizing the practical translational potential of PVTF/COL membranes in clinical GBR applications. Also, include one or two future perspectives (e.g., in vivo testing or long-term mechanical stability under physiological conditions).
Response 6：We have added relevant discussion in the revised manuscript Line 408-412.
Reviewer 3 Report
Comments and Suggestions for AuthorsI have only the following formal comments on the submitted article:
1. The abstract needs to be shortened to max. 200 words, at the end of the abstract, state the main results of the article as well as the measured values/data, and also modify the expression - handleability and et al.
2. The figures need to be renumbered in the text - figure 7 is missing
3. Figures 2, 3, 4, 5, 6, 8 - Their resolution is relatively low, which may affect the readability of the details. If possible, it is recommended to use a higher quality. Also, the round brackets in the figure descriptions should be replaced with square brackets, e.g. (Mpa) to [Mpa]
4. Texts in figures - Some axis descriptions (e.g. in Figure 6) are relatively small, which may make them difficult to read. I recommend increasing the font size in the graphs and ensuring contrast between the text and the background.
5. The conclusion should be written in points, it is necessary to divide it into specific points that will correspond to the measured results. The specific measured values ​​and their percentage comparison should be mentioned in the conclusions.
6. The introduction should be supplemented with citations that deal with various types of polymer composites and their applications in biomedicine. It may be useful to mention PA6 and PA12 composites as an example. For example, Comprehensive review: technological approaches, properties, and applications of pure and reinforced polyamide 6 (PA6) and polyamide 12 (PA12) composite materials.
7. In the discussion, it is also necessary to expand the citations on the possibilities of improving the mechanical properties of composites.Comprehensive review: Optimization of epoxy composites, mechanical properties, & technological trends
Author Response
Thanks for sending us these comments. These comments are very helpful to improve this manuscript.
Comments 1: The abstract needs to be shortened to max. 200 words, at the end of the abstract, state the main results of the article as well as the measured values/data, and also modify the expression - handleability and et al.
Response 1: We have adjusted the abstract to meet the above requirements and corrected expression errors in the revised manuscript Line 15-29.
Comments 2: The figures need to be renumbered in the text - figure 7 is missing
Response 2: We have renumbered the figures in the revised manuscript.
Comments 3: Figures 2, 3, 4, 5, 6, 8 - Their resolution is relatively low, which may affect the readability of the details. If possible, it is recommended to use a higher quality. Also, the round brackets in the figure descriptions should be replaced with square brackets, e.g. (Mpa) to [Mpa]
Response 3: We have corrected the incorrect format and used clearer images in the revised manuscript.
Comments 4: Texts in figures - Some axis descriptions (e.g. in Figure 6) are relatively small, which may make them difficult to read. I recommend increasing the font size in the graphs and ensuring contrast between the text and the background.
Response 4: We have enlarged the text in the relevant figures to make it more readable in the revised manuscript.
Comments 5: The conclusion should be written in points, it is necessary to divide it into specific points that will correspond to the measured results. The specific measured values ​​and their percentage comparison should be mentioned in the conclusions.
Response 5: We have summarized the specific performance changes of the material and drawn conclusions point by point in the revised manuscript Line 388-412.
Comments 6: The introduction should be supplemented with citations that deal with various types of polymer composites and their applications in biomedicine. It may be useful to mention PA6 and PA12 composites as an example. For example, Comprehensive review: technological approaches, properties, and applications of pure and reinforced polyamide 6 (PA6) and polyamide 12 (PA12) composite materials.
Response 6: We have added relevant discussions in the revised manuscript Line 55-64.
Comments 7: In the discussion, it is also necessary to expand the citations on the possibilities of improving the mechanical properties of composites. Comprehensive review: Optimization of epoxy composites, mechanical properties, & technological trends
Response 7: We have added relevant discussions in the revised manuscript Line 333-344.
