Morphology and Properties of Electrospun PCL and Its Composites for Medical Applications: A Mini Review

Round 1

Reviewer 1 Report

The proof offers a good review on morphology and properties of electro spun PCL and

3 its composites for medical applications, based on 83 references. Such review paper is particularly useful to "make a break" in the rapid evolution of manufacturing technologies and approaches of electrospinning technique for medical applications. A focus is proposed more specifically on mechanical and morphology of electrospun nanofibers. Good examples are extracted from the state of the art to discuss on metrology key factors, including mechanical, morphology and biocompatibility behaviors, in relation to chemical properties of polymeric materials and electrospinning parameters. The major part of the proof deals with manufacturing processes to have full control of composition and nanostructure of the materials.

The paper can be [published after considering the following comments:

-       Ref. 83 is listed as Ref [1] after the ref. [82]

-       There are a lot of works in the field involving fabrication of electrospun fibers on metallic surfaces (as a biocompatible layers) or electrospun nanofibers embedded by metallic and/or carbon-based nanomaterials. These hybrid nanofibers have huge impact on different applications including biomedical applications of such nanofibers.

Also, using PCL electrospun nanofibers as coating layer for metallic implants is something that authors need to consider in their review paper.

 

Author Response

Reviewer 1

 

Question/Input

The proof offers a good review on morphology and properties of electro spun PCL and

3 its composites for medical applications, based on 83 references. Such review paper is particularly useful to "make a break" in the rapid evolution of manufacturing technologies and approaches of electrospinning technique for medical applications. A focus is proposed more specifically on mechanical and morphology of electrospun nanofibers. Good examples are extracted from the state of the art to discuss on metrology key factors, including mechanical, morphology and biocompatibility behaviors, in relation to chemical properties of polymeric materials and electrospinning parameters. The major part of the proof deals with manufacturing processes to have full control of composition and nanostructure of the materials.

The paper can be [published after considering the following comments:

-       Ref. 83 is listed as Ref [1] after the ref. [82]

Answer

Noted and corrected, thank you very much.

There are a lot of works in the field involving fabrication of electrospun fibers on metallic surfaces (as a biocompatible layers) or electrospun nanofibers embedded by metallic and/or carbon-based nanomaterials. These hybrid nanofibers have huge impact on different applications including biomedical applications of such nanofibers.

Also, using PCL electrospun nanofibers as coating layer for metallic implants is something that authors need to consider in their review paper.

Answer

Thank you with such valuable point(s) raised above for an improvement of the overall manuscript.   Table 4 addresses different nanofillers, component systems, biomedical applications and the average diameters of the electro-spun PCL/fiber nanocomposite. Amongst this nanofillers in Table 4, metals/hybrid systems (highlighted in Table 4) such as Ti (coated), Nanodiamond, ZnO, reduced graphene etc. were investigated and their results are tabulated in Table 4. Furthermore, because we wrote a mini review, only recent article/studies were added in this section/Table. Once again, thank you very much with valuable point(s) for an improvement of the manuscript.

Author Response File: Author Response.pdf

Reviewer 2 Report

I have revised this review manuscript focused on the development of electrospun PCL fiber-based materials for biomedical applications. The auhtors have compiled a nice amount of research but they lack to provide a detail explanation of the progress and state of these material in the field of the study. Please carefully consider the following points:

Please revise the English language and expressions along the manuscript. See, for instance, the sentence in the abstract: "Combining the inherent properties of the PCL with the characteristic of a nanofibrous structures, results in a promising material that can BE suitable for different applications, including the biomedical applications". Or the sentence: "Figure 1 demonstrates the number of annual publications related to the electrospinning of polymeric fibres, which shows that since 2003, the number of the annual publications related to “electrospinning”, has grown from between 10-3000 and ~243 (for the year 2018) for electrospinning of + PCL alone."

Please check the style of the figure captions.

Electrospinning and then also "electrospun" is habitually a single word. Please check literature and modify it in the whole text.

I suggest authors to include a few previous reviews on the use of electrospining for active and bioactive applications in section 2.

Section 5 should be fully explained in the text. As this is the core of the article and the main topic of the review, the authos failed to provide a very complete and detailed information about the development of PCL materials by electrospinning and the resultant biomedical devices and articles. Authors are encouraged to further explain the provided information with examples, images, data, promising results, drawbacks, etc. of the most relevant studies. This constitutes the basis of the article and the information at this moment is only supported by a paragraph and a table.

Section 6 describes the mechanical properties of the electrospun PCL materials. Since these materials are composed of fibers and the porosity of the mats is extremely high, their mechanical properties are habitually very poor. The added information is then unaccurate and authors should describe the actual properties and limitations of these materials. I also recommend to include some mechanical data to replace the column "Reason" (similar to Table 3).

Author Response

Reviewer 2

Question/input

I have revised this review manuscript focused on the development of electrospun PCL fiber-based materials for biomedical applications. The authors have compiled a nice amount of research but they lack to provide a detail explanation of the progress and state of these material in the field of the study. Please carefully consider the following points:

Please revise the English language and expressions along the manuscript. See, for instance, the sentence in the abstract: "Combining the inherent properties of the PCL with the characteristic of a nanofibrous structures, results in a promising material that can BE suitable for different applications, including the biomedical applications". Or the sentence: "Figure 1 demonstrates the number of annual publications related to the electrospinning of polymeric fibres, which shows that since 2003, the number of the annual publications related to “electrospinning”, has grown from between 10-3000 and ~243 (for the year 2018) for electrospinning of + PCL alone."

Answer                           

 

Thank you for noting such an important fact, the above sentence (s) has been corrected. Please check the highlighted paragraph on page 1.

 

Question/input

Please check the style of the figure captions.

Answer

The style of Figure captions has been corrected; please see the highlighted Figures from 1 to 5 in the manuscript.

Question/input

Electrospinning and then also "electrospun" is habitually a single word. Please check literature and modify it in the whole text.

Answer

It has been corrected as electrospun according to the literature, thank you once again with a valuable point.

 

Question/input

I suggest authors to include a few previous reviews on the use of electrospining for active and bioactive applications in section 2.

A paragraph on bioactive and active studies on PCL was added in section 2 as suggested by the reviewer. Please check a new paragraph on page 4 lines 115 to line 141. 

Question/input:

 

Section 5 should be fully explained in the text. As this is the core of the article and the main topic of the review, the authors failed to provide a very complete and detailed information about the development of PCL materials by electrospinning and the resultant biomedical devices and articles. Authors are encouraged to further explain the provided information with examples, images, data, promising results, drawbacks, etc. of the most relevant studies. This constitutes the basis of the article and the information at this moment is only supported by a paragraph and a table.

Answer

The reviewer highlighted important parameters such as images and data which were missing in this review. An expanded text on biomedical application together with data and images/Figures were added. Figure 4 and 5 together with their text for biomedical applications were added on page 10 and 11.

Question/input

Section 6 describes the mechanical properties of the electrospun PCL materials. Since these materials are composed of fibers and the porosity of the mats is extremely high, their mechanical properties are habitually very poor. The added information is then unaccurate and authors should describe the actual properties and limitations of these materials. I also recommend to include some mechanical data to replace the column "Reason" (similar to Table 3).

Answer

Thank you once again with a valuable point(s). Table 4 (Different solvent systems, mechanical properties of the electrospun PCL/fiber composites) under the heading: Mechanical properties and observations describe the actual properties obtained by various studies and furthermore the subsection “reason” was replaced by mechanical properties and observation in Table 4.  Thank you once again with valuable inputs for an improvement of the overall manuscript

Round 2

Reviewer 2 Report

The authors have sucessfully corrected the different questions arised during the revision and the quality of the manuscript has improved. I have only noticed that the word "electrospinning" and "electrospun" is written either in one or two words and therefore it is still no homogeneuos along the text (please see for instance the title). I recomend to amend these expresion and also the English style and then accept the manuscript in its present form.

Author Response

Question/input

The authors have sucessfully corrected the different questions arised during the revision and the quality of the manuscript has improved. I have only noticed that the word "electrospinning" and "electrospun" is written either in one or two words and therefore it is still no homogeneuos along the text (please see for instance the title). I recomend to amend these expresion and also the English style and then accept the manuscript in its present form.

Answer:

Thank you once again to the reviewer for recognizing that electrospun and electrospinning are not consistent in the text. That has been noted and corrected.  Minor English mistakes has been noted and corrected. Please check highlighted red text for corrections. Thank you once again for your input in improving the manuscript. 

Author Response File: Author Response.docx