Hyaluronic Acid-Based Biomaterials in Tissue Engineering: From Molecular Properties to Re-Generative Applications

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

• Lack of novelty

The manuscript does not demonstrate a clear or meaningful distinction from the numerous existing reviews on hyaluronic acid-based biomaterials, and its originality is not convincingly established.

• Overly descriptive content

The review primarily summarizes known information without sufficient critical evaluation or analytical depth, limiting its scientific contribution.

• Superficial treatment of key challenges

Important issues, including molecular weight effects, mechanical limitations, and clinical translation barriers, are addressed only briefly and without adequate critical discussion.

• Weak structure–function analysis

The connection between material properties, design strategies, and biological performance is not sufficiently developed.

• Outdated and incomplete literature coverage

Recent and high-impact studies are not adequately included, reducing the relevance of the review.

• Lack of synthesis and comparison

The manuscript does not provide meaningful integration or comparative analysis of the literature, which is essential for a high-quality review.

• What is the novelty of this review?
• Please provide the schematic representation of hyaluronic acid for applications.
• Check the keywords.
• Please include a comparative table summarizing tissue-engineering applications.
• What are the limitations of this review?
• The manuscript would benefit from improved organization and clearer transitions between sections.
• Language and phrasing require minor editing for clarity and readability.
• Some sections are overly general and could be made more concise and focused.

 

Comments on the Quality of English Language

• Lack of novelty

The manuscript does not demonstrate a clear or meaningful distinction from the numerous existing reviews on hyaluronic acid-based biomaterials, and its originality is not convincingly established.

• Overly descriptive content

The review primarily summarizes known information without sufficient critical evaluation or analytical depth, limiting its scientific contribution.

• Superficial treatment of key challenges

Important issues, including molecular weight effects, mechanical limitations, and clinical translation barriers, are addressed only briefly and without adequate critical discussion.

• Weak structure–function analysis

The connection between material properties, design strategies, and biological performance is not sufficiently developed.

• Outdated and incomplete literature coverage

Recent and high-impact studies are not adequately included, reducing the relevance of the review.

• Lack of synthesis and comparison

The manuscript does not provide meaningful integration or comparative analysis of the literature, which is essential for a high-quality review.

• What is the novelty of this review?
• Please provide the schematic representation of hyaluronic acid for applications.
• Check the keywords.
• Please include a comparative table summarizing tissue-engineering applications.
• What are the limitations of this review?
• The manuscript would benefit from improved organization and clearer transitions between sections.
• Language and phrasing require minor editing for clarity and readability.
• Some sections are overly general and could be made more concise and focused.

 

Author Response

1. Summary

Thank you very much for these valuable comments. We carefully revised the manuscript in response to all of the points raised.
To better establish the novelty of this review, we repositioned it as a more integrated and mechanistically oriented article linking HA molecular properties, chemical modification, receptor-mediated signaling, and tissue-engineering applications. We also added a dedicated section on the mechanistic links between HA physicochemical properties and cellular responses, and expanded the Discussion to more critically address molecular weight effects, mechanical limitations, degradation, and clinical translation challenges. To improve synthesis and comparison, we added summary tables on HA crosslinking methods, comparison with other natural polymers, and representative HA-based scaffolds across tissue-engineering applications. We also included a dedicated section on 3D bioprinting of HA-based bioinks and expanded the section on HA chemical modification to include more recent and relevant strategies. In addition, we added a schematic figure, updated the keywords, improved organization and transitions, and thoroughly edited the manuscript for language, clarity, and readability. We sincerely appreciate the reviewer’s suggestions, which significantly improved the quality of this review.

2. Comments and Suggestions for Authors
Comments 1: Lack of novelty: The manuscript does not demonstrate a clear or meaningful distinction from the numerous existing reviews on hyaluronic acid-based biomaterials, and its originality is not convincingly established.

Response 1: Thank you for this important comment. We agree that the originality of the previous version was not presented clearly enough. In the revised manuscript, we have repositioned this review to emphasize its distinctive contribution as an integrated and mechanistically oriented analysis, linking HA molecular properties, chemical modification strategies, receptor-mediated signaling, and tissue-engineering applications. Specifically, we have introduced a new section that establishes a mechanistic framework connecting HA physicochemical properties (e.g., molecular weight, matrix mechanics, and hydration) with cellular responses and biological outcomes. In addition, we have expanded the discussion of key challenges and incorporated comparative tables to enhance cross-study analysis and synthesis.

1. We believe these revisions significantly improve the conceptual depth and clearly distinguish this work from existing descriptive reviews. We have added Table 1. on page 8, line 306 and highlighted it in red. [Table 1. Hyaluronic acid crosslinking methods: representative reagents, reaction conditions, advantages and limitations.]
2. We have added Table 2. on page 13, line 430 and highlighted it in red. [Table 2. Brief comparison of hyaluronic acid with other natural polymers commonly used in tissue engineering.]
3. We have added Table 3. on page 15, line 445 and highlighted it in red. [Table 3. Representative HA-based scaffolds classified by tissue type: composition, cell type, key findings, limitations, and references.]
4. We added Section 5 on page 11, line 356-406 and high lighted it in red [5.MechanisticLinks Between HA Physicochemical Properties and Cellular Responses...]
5. We added Section 6 on page 12, line 407-429 and highlighted it in red. [6. Natural Polymer Comparison in Tissue Engineering...]
6. We added Section 7.5 on page 22, line 664-709 and highlighted it in red. [7.5 Bioprinting of HA-Based Bioinks...]

Comments 2: Overly descriptive content: The review primarily summarizes known information without sufficient critical evaluation or analytical depth, limiting its scientific contribution. Superficial treatment of key challenges Important issues, including molecular weight effects, mechanical limitations, and clinical translation barriers, are addressed only briefly and without adequate critical discussion.

Response 2: Thank you for this important comment. We agree that the previous version was overly descriptive and lacked sufficient critical evaluation. To address this issue, we have substantially revised the manuscript to incorporate a more analytical and critical perspective. Specifically, we added a dedicated section on the mechanistic links between HA physicochemical properties and cellular responses, and expanded the discussion of key challenges—including molecular weight–dependent effects, mechanical limitations, degradation behavior, immunomodulatory complexity, and barriers to clinical translation— throughout the manuscript rather than treating them briefly. In addition, Table 3 has been introduced to provide a structured comparison of representative HA-based scaffolds, including composition, cell types, key findings, and limitations. These revisions shift the manuscript from a descriptive summary to a more critical and integrative review.

1. We added Section 5 on page 11, line 356-406 and high lighted it in red.[5.MechanisticLinks Between HA Physicochemical Properties and Cellular Responses...]
2. We have added Table 3. on page 15, line 445 and highlighted it in red. [Table 3. Representative HA-based scaffolds classified by tissue type: composition, cell type, key findings, limitations, and references.]

Comments 3: Weak structure–function analysis: The connection between material properties, design strategies, and biological performance is not sufficiently developed.

Response 3: Thank you for this insightful comment. We agree that the structure–function relationship was not sufficiently developed in the previous version. In the revised manuscript, we have explicitly strengthened the connection between HA material properties, design strategies, and biological performance. Specifically, we clarified how parameters such as molecular weight, stiffness, viscoelasticity, degradation behavior, and hydration influence scaffold design (e.g., chemical modification and crosslinking) and ultimately determine cellular responses. A dedicated mechanistic section has been added to illustrate how these factors regulate receptor-mediated signaling, mechanotransduction, and tissue-specific outcomes. We believe these revisions substantially improve the structure–function analysis and enhance the conceptual coherence of the manuscript.

1. We have added Table 1. on page 8, line 306 and highlighted it in red. [Table 1. Hyaluronic acid crosslinking methods: representative reagents, reaction conditions, advantages and limitations.]
2. We added Section 5 on page 11, line 356-406 and highlighted it in red. [5. Mechanistic Links Between HA Physicochemical Properties and Cellular Responses...]

Comments 4: Outdated and incomplete literature coverage: Recent and high-impact studies are not adequately included, reducing the relevance of the review.
Response 4: Thank you for this valuable comment. We agree that the literature coverage required further updating and expansion. Accordingly, we have incorporated recent and high-impact studies across multiple sections, including HA chemical modification, degradation mechanisms, mechanistic structure–function relationships, 3D bioprinting, and tissue-engineering applications. These additions not only improve the timeliness of the manuscript but also strengthen its relevance and comprehensiveness.

1. We added Section 7.5 on page 22, line 664-709 and highlighted it in red. [7.5 Bioprinting of HA-Based Bioinks...]
2. We have added the relevant paragraph on page 5, line 190-197 and highlighted it in red. [HA degradation is mediated by a family of enzymes...]
3. We have added the relevant paragraph on page 5, line 205-213 and highlighted it in red. [For example, ultrasound-mediated degradation provides a convenient...]
4. We have added the relevant paragraph on page 7, line 277-293 and highlighted it in red. [Tyramine modification is an important and widely used strategy for HA functionalization...]
5. We have added Table 1. on page 8, line 301 and highlighted it in red. [Table 1. Hyaluronic acid crosslinking methods: representative reagents, reaction conditions, advantages and limitations.]

Comments 5: Lack of synthesis and comparison: The manuscript does not provide meaningful integration or comparative analysis of the literature, which is essential for a high-quality review. What is the novelty of this review? Please provide the schematic representation of hyaluronic acid for applications. Check the keywords. Please include a comparative table summarizing tissue-engineering applications. What are the limitations of this review? The manuscript would benefit from improved organization and clearer transitions between sections. Language and phrasing require minor editing for clarity and readability. Some sections are overly general and could be made more concise and focused.

Response 5: Thank you very much for these constructive and comprehensive comments. We agree that the previous version lacked sufficient synthesis, comparison, and a clearly defined novelty. In response, we have substantially revised the manuscript to improve its integration, analytical depth, and overall organization. First, we clarified the novelty by repositioning the review as a mechanistically oriented and integrative framework linking HA molecular properties, chemical modification, receptor-mediated signaling, and tissue- engineering applications. Second, we introduced comparative tables (Tables 1–3) and a graphical abstract to enhance cross-study comparison and visual clarity. Third, we improved manuscript organization by restructuring sections and adding clearer transitions to ensure logical flow. Finally, we revised the manuscript extensively for language clarity, conciseness, and readability. We sincerely appreciate the reviewer’s suggestions, which have significantly improved the quality, clarity, and scientific contribution of this review.

1.  We have added Table 1. on page 8, line 306 and high lighted it in red. [Table1.Hyaluronic acid crosslinking methods: representative reagents, reaction conditions, advantages and limitations.]
2. We have added Table 2. on page 13, line 430 and highlighted it in red. [Table 2. Brief comparison of hyaluronic acid with other natural polymers commonly used in tissue engineering.]
3. We have added Table 3. on page 15, line 445 and highlighted it in red. [Table 3. Representative HA-based scaffolds classified by tissue type: composition, cell type, key findings, limitations, and references.]
4. We added Section 5 on page 11, line 356-406 and high lighted it in red. [5.MechanisticLinks Between HA Physicochemical Properties and Cellular Responses...]
5. We added Section 6 on page 12, line 407-429 and highlighted it in red. [6. Natural Polymer Comparison in Tissue Engineering...]
6. We updated the keywords to hyaluronic acid; hydrogel modification; tissue engineering; regenerative medicine; HA binding receptor; 3D bioprinting (page 1, line 35-36).
7. We have thoroughly reviewed and revised the manuscript for grammar, wording, and overall language clarity.
8. We added a graphical abstract.

3. Additional clarifications

1. As substantial new content and mechanistic analysis have been incorporated, we have rewritten the Conclusion (page 24, line 749-782) and Abstract (page 1, line 18-34) section to better reflect the revised scope and key messages of the manuscript.

2. We have provided a list of abbreviations (page 25, line 792) to improve readability and consistency throughout the manuscript.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The presented review is devoted to hyaluronic acid-based biomaterials for tissue engineering and regenerative medicine. The authors summarize such topics as: synthesis, physicochemical properties, biodegradation, and biological functions of HA; chemical modification and crosslinking strategies for fabricating HA-based biomaterials; HA interactions with cell-surface receptors and associated signaling pathways; applications of HA-based scaffolds in bone, cartilage, blood vessel, and skin/soft tissue engineering.

Comments:

1. Page 2, lines 63-69. The extraordinary properties of HA should be mentioned to show the unique possibilities provided by HA. Otherwise there is no difference with other polysaccharides.
2. The manuscript lacks visual content. (1) different chemical structures of HA are missing (page 3, lines 91-95). (2) some general scheme, which explains the review structure and flow.
3. Pages 3-4. During discussion of HA Properties, Biological functions and Degradation there authors do not give information on how this or that factor affect the process, but just say that this or that could have an effect. So the discussion is too descriptive and requires some more specific information.
4. Figure 4 subpanels (a–k) are listed, but not all clearly described in text.
5. The summary tables are missing. Please add such tables as: Table 1: HA crosslinking methods (reagents, reaction conditions, advantages, limitations); Table 2: HA-based scaffolds by tissue type (composition, cell type, key findings, limitations).
6. Comparison with other natural polymers is missing. Brief comparison table (collagen, alginate, chitosan vs HA) would contextualize HA's unique advantages.
7. Discussion on 3D bioprinting is definitely missing. It was mentioned in references, but not properly elaborated within the text. However, this is a major emerging area for HA-based bioinks.
8. Proofread for typos – Examples:

Page 3: "HA synthetase" should be "HA synthase" (consistent with established nomenclature)

Page 10: "mixing HA with CS and ALG" – define abbreviations (chitosan, alginate)

Page 12: "non- treated" → "untreated"

Author Response

1. Summary

Thank you very much for these valuable comments. We have carefully revised the manuscript in response to all of the points raised. In the revised version, we have substantially improved the conceptual clarity, mechanistic depth, and overall organization of the manuscript. Specifically, we strengthened the Introduction and HA property sections to better highlight the unique features of HA, added new visual content including an updated Figure 1, and improved the overall structure and flow of the review.We also revised the sections on HA properties, biological functions, and degradation to provide more mechanistic and specific discussion rather than descriptive statements, and expanded the corresponding figure descriptions for better clarity. In addit ion, we added summary tables on HA crosslinking methods, comparison with other natural polymers, and representative HA-based scaffolds by tissue type. A dedicated section on 3D bioprinting of HA-based bioinks was also included. Finally, we thoroughly proofread the manuscript and corrected grammar, wording, abbreviations, and typographical issues throughout. We believe these revisions have significantly improved the scientific depth, clarity, and overall impact of the manuscript.

2. Point-by-point response to Comments and Suggestions for Authors
Comments 1: Page 2, lines 63-69. The extraordinary properties of HA should be mentioned to show the unique possibilities provided by HA. Otherwise there is no difference with other polysaccharides.

Response 1: Thank you for this valuable comment. We agree that the unique properties of HA were not sufficiently emphasized in the previous version, which may have made its distinction from other polysaccharides unclear. In the revised manuscript, we have strengthened the Introduction and the section on HA properties to better highlight the extraordinary features of HA, including its native presence in the mammalian extracellular matrix, non-sulfated glycosaminoglycan structure, exceptional water-binding capacity, viscoelasticity, space-filling behavior, and receptor-mediated biological activity through molecules such as CD44 and RHAMM. We also added a comparative discussion with other natural polymers to further clarify the distinctive advantages of HA in tissue engineering and regenerative medicine.

1. We have added the relevant paragraph on page2, line 63-80, and high lighted it in red. [Among natural polysaccharides, HA is particularly distinctive because it is a native...]

Comments 2: The manuscript lacks visual content. (1) different chemical structures of HA are missing (page 3, lines 91-95). (2) some general scheme, which explains the review structure and flow.

Response 2: Thank you for this helpful suggestion. We agree that the previous version lacked sufficient visual content to guide readers. In response, we revised Figure 1 to include the chemical structure of HA together with representative modification strategies and their biomedical relevance, thereby improving the clarity of structure–function relationships. In addition, we reorganized the manuscript to improve section flow and introduced a clearer schematic framework that outlines the progression from HA molecular properties to chemical modification, receptor interactions, and tissue-engineering applications.

1. We have added the relevant paragraph on page 4, line 136-146, and high lighted it in red. [Figure 1b illustrates the functional versatility of HA by summarizing its representative chemical bonding modes and their corresponding biomedical applications...]
2. We added Figure 1 on page 3, line 99-105.

Comments 3: Pages 3-4. During discussion of HA Properties, Biological functions and Degradation there authors do not give information on how this or that factor affect the process, but just say that this or that could have an effect. So the discussion is too descriptive and requires some more specific information.

Response 3: Thank you for this insightful comment. We agree that the previous version was overly descriptive. In response, we revised these sections to provide more mechanistic and quantitatively informed discussion rather than general descriptive statements. Specifically, we clarified how HA molecular weight influences receptor-mediated signaling and inflammatory responses, how physicochemical properties such as stiffness, viscoelasticity, and hydration regulate cell behavior and mechanotransduction, and how degradation processes generate bioactive HA fragments with distinct biological functions. Furthermore, we integrated these aspects into a dedicated section (“Mechanistic Links Between HA Physicochemical Properties and Cellular Responses”) to establish clearer connections between material properties and biological outcomes.

1. We have added the relevant paragraph on page 4, line 119-132 and high lighted it in red. [HA is highly hydrophilic because its repeating disaccharide units...]

2. Wehaveaddedtherelevantparagraphonpage5,line181-188andhighlighteditinred. [in cancer-related contexts, HA accumulation...]

3. We have added the relevant paragraph on page 5, line 190-197 and high lighted it in red. [HA degradation is mediated by a family of enzymes known as...]

4. We have added the relevant paragraph on page 5, line 199-213 and high lighted it in red. [Non-enzymatic degradation can be triggered by acidic or alkaline conditions...]

5. We added Section 5 on page 11, line 356-406 and highlighted it in red. [5. Mechanistic Links Between HA Physicochemical Properties and Cellular Responses...]

Comments 4: Figure 4 subpanels (a–k) are listed, but not all clearly described in text.
Response 4: Thank you for this careful comment. We agree that not all subpanels were clearly described in the previous version. In the revised manuscript, we have expanded the corresponding descriptions to explicitly interpret each subpanel and clarify its relevance to the overall findings. In addition, because a new Figure 1 was added during revision, the original Figure 4 has been renumbered as Figure 5 throughout the manuscript.

1. We have added the relevant paragraph on page 21, line 625-652 and high lighted it in red. [Delayed healing and excessive scar formation remain major challenges...]

Comments 5: The summary tables are missing. Please add such tables as: Table 1: HA crosslinking methods (reagents, reaction conditions, advantages, limitations); Table 2: HA-based scaffolds by tissue type (composition, cell type, key findings, limitations).
Response 5: Thank you for this helpful suggestion. We agree that summary tables are important for improving the clarity and practical value of the review. In the revised manuscript, we have added a summary table of HA crosslinking methods that includes representative reagents, reaction conditions, advantages, and limitations (Table 1). We also added a comparative table summarizing representative HA-based scaffolds for different tissue-engineering applications, including scaffold composition, cell type, key findings, and limitations. Because an additional comparison table was also introduced during revision, this tissue-engineering summary now appears as Table 3 in the revised manuscript. These additions provide structured comparison and significantly improve the accessibility, clarity, and practical value of the review.

1. We have added Table 1.on page 8, line 306 and high lighted it in red. [Table1. Hyaluronic acid crosslinking methods: representative reagents, reaction conditions, advantages and limitations.]

2. We have added Table 3. on page 15, line 445 and high lighted it in red. [Table3. Representative HA-based scaffolds classified by tissue type: composition, cell type, key findings, limitations, and references.]

Comments 6: Comparison with other natural polymers is missing. Brief comparison table (collagen, alginate, chitosan vs HA) would contextualize HA's unique advantages.
Response 6: Thank you for this valuable suggestion. We agree that a comparison with other commonly used natural polymers is important to better contextualize the distinctive advantages of HA. In the revised manuscript, we added a new comparative section and a summary table comparing HA with collagen, alginate, and chitosan in terms of their main advantages, limitations, and distinctive features in tissue engineering. This comparison is now presented as Table 2, and it helps clarify the unique value of HA as a native extracellular- matrix glycosaminoglycan with high hydration, viscoelasticity, and receptor-mediated biological activity. This addition strengthens the comparative perspective and further highlights the unique position of HA among natural biomaterials.

1. We added Section 6 on page 11, line 407-429 and highlighted it in red. [6. Natural Polymer Comparison in Tissue Engineering...]

2. We have added Table 2. on page 13, line 430 and highlighted it in red. [Table 2. Brief comparison of hyaluronic acid with other natural polymers commonly used in tissue engineering.]

Comments 7: Discussion on 3D bioprinting is definitely missing. It was mentioned in references, but not properly elaborated within the text. However, this is a major emerging area for HA-based bioinks.

Response 7: Thank you for this important comment. We agree that 3D bioprinting was insufficiently discussed in the previous version despite its growing importance in the field of HA-based biomaterials. In response, we added a dedicated section, “Bioprinting of HA-Based Bioinks,” to more fully discuss the role of HA in 3D bioprinting. In this section, we describe the rationale for using HA as a bioink component, the limitations of native HA, the need for chemical modification such as methacrylation, key material requirements including rheological behavior and printability, and recent tissue-engineering applications of HA-based bioinks. We believe this addition has significantly improved the completeness and timeliness of the review.

1. We added Section 7.5 on page 22, line 664-709 and highlighted it in red. [7.5 Bioprinting of HA-Based Bioinks...]

Comments 8: Proofread for typos – Examples:
Page 3: "HA synthetase" should be "HA synthase" (consistent with established nomenclature)
Page 10: "mixing HA with CS and ALG" – define abbreviations (chitosan, alginate)
Page 12: "non- treated" → "untreated"
Response 8: Thank you for your valuable suggestions. We have systematically reviewed and revised the manuscript for grammar, wording, and overall language clarity. In addition, we have provided a list of abbreviations to improve readability and consistency throughout the manuscript.

1. We added abbreviation table on page 25, line 792.

3. Additional clarifications

As substantial new content and mechanistic analysis have been incorporated, we have accordingly rewritten the Conclusion (page 24, line 749-782) and Abstract (page 1, line 18-34) section to better reflect the revised scope and major messages of the review.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Manuscript ID:　 jfb-4276795

Manuscript Title:

Hyaluronic Acid-Based Biomaterials in Tissue Engineering: From Molecular Properties to Re-generative Applications.

General Evaluation

This manuscript presents a comprehensive overview of hyaluronic acid (HA)-based biomaterials and their applications in tissue engineering and regenerative medicine. The topic is timely and relevant, given the increasing interest in HA-derived scaffolds, hydrogels, and biofabrication approaches. However, while the manuscript provides a wide scope of information, it remains largely descriptive and lacks the level of critical analysis expected for a high-quality review article. The discussion of existing literature is mainly summarized without sufficient comparison, synthesis, or extraction of key design principles. In particular, deeper mechanistic insights linking HA properties (e.g., molecular weight, crosslinking, stiffness, and degradation) to specific cellular responses are insufficiently addressed. Additionally, emerging areas such as 3D bioprinting and advanced biofabrication are only briefly mentioned and would benefit from more structured and in-depth discussion.

 

Overall, the manuscript has a solid foundation and compiles relevant literature; however, significant revisions are required to enhance its scientific depth, critical perspective, and clarity before it can be considered for publication.

Overall recommendation: Major Revision

 

1. The manuscript reads as a compilation of literature rather than a critical review. The authors should include comparative analysis, identify trends, and extract design principles for HA-based biomaterials.

 

2. The manuscript lacks mechanistic insight linking HA physicochemical properties (e.g., stiffness, molecular weight, degradation) to specific cellular responses. Incorporating pathways such as CD44-mediated signaling, mechanotransduction, and ECM mimicry would significantly strengthen the review.

 

3. Emerging technologies such as 3D bioprinting and HA-based bioinks are insufficiently covered. A dedicated section discussing fabrication strategies, printability, and structure function relationships is necessary.

 

4. The manuscript would benefit from summary tables comparing different HA modification strategies, crosslinking methods, and their resulting mechanical and biological properties.

 

5. The manuscript requires thorough English editing for grammar, clarity, and scientific precision.

 

6. In Section 2.4 (Degradation), ultrasonic treatment is briefly mentioned as a non-enzymatic degradation mechanism; however, relevant literature is not adequately cited. The authors are encouraged to include recent studies on ultrasonic degradation of HA to provide more detailed insight into this process.
   https://doi.org/10.3390/biom14050604

 

7. The current discussion of HA chemical modification is incomplete. Important and widely used approaches, such as tyramine-modified HA and enzymatic crosslinking systems (e.g., HRP/H₂O₂-mediated gelation) and photocroslinking , are not included. Incorporating these strategies would significantly improve the completeness and relevance of this review.
   https://doi.org/10.1002/adhm.202303787

 

 

 

 

Author Response

1. Summary

Thank you very much for these valuable comments. We have carefully revised the manuscript to address all of the concerns raised. In the revised version, we have substantially strengthened the manuscript by transforming it from a descriptive summary into a more critical, integrative, and mechanistically oriented review, by adding comparative analysis, emphasizing broader literature trends, and highlighting key design considerations for HA- based biomaterials. We also added a dedicated mechanistic section to better connect HA physicochemical properties, such as molecular weight, degradation, and matrix mechanics, with cellular responses including receptor-mediated signaling, mechanotransduction, and ECM mimicry. This section establishes a clearer structure–function framework linking material properties to biological outcomes. In addition, we included a dedicated section on 3D bioprinting of HA-based bioinks, added summary tables on HA crosslinking methods and representative HA-based scaffolds, expanded the Degradation section with recent literature on ultrasonic degradation, and revised the Chemical modification of HA section to include tyramine-modified HA, HRP/H2O2-mediated gelation, and photocrosslinking. Finally, the manuscript was thoroughly edited for English grammar, clarity, and scientific precision. We believe these revisions have significantly improved the conceptual depth, clarity, and overall scientific contribution of this review.

2. Point-by-point response to Comments and Suggestions for Authors
Comments 1: The manuscript reads as a compilation of literature rather than a critical review. The authors should include comparative analysis, identify trends, and extract design principles for HA- based biomaterials.

Response 1: Thank you for this important comment. We agree that the previous version was too descriptive and did not provide sufficient critical synthesis of the literature. In response, we revised the manuscript to substantially strengthen its analytical and integrative perspective, by adding comparative tables, a dedicated section on the mechanistic links between HA physicochemical properties and cellular responses, and expanding the discussion to explicitly connect molecular weight, degradation behavior, receptor interactions, and matrix mechanics with biological performance. We also emphasized broader trends across the literature and identified key design principles for HA-based biomaterials, such as balancing hydration, degradability, mechanical stability, and bioactivity according to the target tissue application.

1. These revisions transform the manuscript from a descriptive compilation into a more critical, mechanism-informed, and design-oriented review. We have added Table 1. on page 8, line 306 and highlighted it in red. [Table 1. Hyaluronic acid crosslinking methods: representative reagents, reaction conditions, advantages and limitations.]

2. We have added Table 2. on page 13, line 430 and highlighted it in red. [Table 2. Brief comparison of hyaluronic acid with other natural polymers commonly used in tissue engineering.]

3. WehaveaddedTable3.onpage15,line445andhighlighteditinred.[Table3. Representative HA-based scaffolds classified by tissue type: composition, cell type, key findings, limitations, and references.

4. We added Section 5 on page 11, line 356-406 and highlighted it in red. [5. Mechanistic Links Between HA Physicochemical Properties and Cellular Responses...]

5. We added Section 6 on page 11, line 407-429 and highlighted it in red. [6. Natural Polymer Comparison in Tissue Engineering...]

6. We added Section 7.5 on page 22, line 664-709 and highlighted it in red. [7.5 Bioprinting of HA-Based Bioinks...]

7. We added Figure 1 on page 3, line 99-105.

Comments 2: The manuscript lacks mechanistic insight linking HA physicochemical properties (e.g., stiffness, molecular weight, degradation) to specific cellular responses. Incorporating pathways such as CD44-mediated signaling, mechanotransduction, and ECM mimicry would significantly strengthen the review.

Response 2: Thank you for this insightful comment. We agree that the previous version did not sufficiently explain the mechanistic links between HA physicochemical properties and specific cellular responses. In response, we added a dedicated section, “Mechanistic Links Between HA Physicochemical Properties and Cellular Responses,” to strengthen this aspect of the review. In the revised manuscript, we now discuss how HA molecular weight influences receptor-mediated signaling, particularly through CD44 and RHAMM; how stiffness, viscoelasticity, and stress relaxation regulate cell behavior via mechanotransduction; and how the highly hydrated nature of HA contributes to ECM mimicry and downstream cellular processes.

1. Importantly, this section establishes a clearer structure–function framework linking material design parameters to biological outcomes. We added Section 5 on page 11, line 356-406 and highlighted it in red. [5. Mechanistic Links Between HA Physicochemical Properties and Cellular Responses...]

Comment 3: Emerging technologies such as 3D bioprinting and HA-based bioinks are insufficiently covered. A dedicated section discussing fabrication strategies, printability, and structure function relationships is necessary.
Response 3: Thank you for this important comment. We agree that the previous version did not sufficiently cover emerging technologies such as 3D bioprinting and HA-based bioinks. In response, we added a dedicated section on Bioprinting of HA-Based Bioinks, in which we discuss fabrication strategies, printability-related considerations, chemical modification for bioink design, and the relationship between material properties and biological performance. We believe this addition has substantially improved the completeness and timeliness of the review.

1. We added Section 7.5 on page 22, line 664-709 and highlighted it in red. [7.5 Bioprinting of HA-Based Bioinks...]

Comment 4: The manuscript would benefit from summary tables comparing different HA modification strategies, crosslinking methods, and their resulting mechanical and biological properties.
Response 4: Thank you for this helpful suggestion. We agree that summary tables are important for improving clarity and comparative analysis. In the revised manuscript, we added Table 1 to summarize major HA crosslinking methods, including representative reagents, reaction conditions, advantages, and limitations. We also expanded the discussion of HA modification strategies in the main text and included comparative application-oriented summaries in Tables 2 and 3, which help relate modification and scaffold design to their biological relevance and tissue-engineering performance. These additions provide structured comparison and significantly enhance the clarity, accessibility, and practical value of the review, particularly in linking modification strategies with mechanical and biological performance.

1. We have added Table 1. on page 8, line 306 and highlighted it in red. [Table 1. Hyaluronic acid crosslinking methods: representative reagents, reaction conditions, advantages and limitations.]
2. We have added Table 2. on page 13, line 430 and highlighted it in red. [Table 2. Brief comparison of hyaluronic acid with other natural polymers commonly used in tissue engineering.]
3. We have added Table 3. on page 15, line 445 and highlighted it in red. [Table 3. Representative HA-based scaffolds classified by tissue type: composition, cell type, key findings, limitations, and references.]

Comment 5: The manuscript requires thorough English editing for grammar, clarity, and scientific precision.

Response 5: Thank you for your valuable suggestions. We have systematically revised the manuscript for grammar, terminology consistency, and overall scientific clarity, ensuring improved readability throughout.

Comment 6: In Section 2.4 (Degradation), ultrasonic treatment is briefly mentioned as a non- enzymatic degradation mechanism; however, relevant literature is not adequately cited. The authors are encouraged to include recent studies on ultrasonic degradation of HA to provide more detailed insight into this process. https://doi.org/10.3390/biom14050604

Response 6: Thank you for this helpful suggestion. We agree that the discussion of ultrasonic degradation in the previous version was too brief and lacked sufficient supporting literature. In response, we have added the recommended recent study (DOI: 10.3390/biom14050604) to the Degradation section and expanded the corresponding discussion to provide more specific insight into ultrasonic treatment as a non-enzymatic mechanism for HA degradation. We believe this revision has improved the completeness and clarity of the degradation-related discussion.

1. We have added the relevant paragraph on page 5, line 190-197 and highlighted it in red. [HA degradation is mediated by a family of enzymes...]
2. We have added the relevant paragraph on page 5, line 205-213 and highlighted it in red. [For example, ultrasound-mediated degradation provides a convenient...]

Comment 7: The current discussion of HA chemical modification is incomplete. Important and widely used approaches, such as tyramine-modified HA and enzymatic crosslinking systems (e.g., HRP/H2O2- mediated gelation) and photocroslinking , are not included. Incorporating these strategies would significantly improve the completeness and relevance of this review. https://doi.org/10.1002/adhm.202303787

Response 7: Thank you for this valuable comment. We agree that the previous version did not sufficiently cover several important and widely used HA modification strategies. In response, we have expanded the Chemical modification of HA section to include tyramine-modified HA, HRP/H2O2-mediated enzymatic gelation, and photocrosslinking approaches. We also added the suggested recent study (DOI: 10.1002/adhm.202303787) to support the discussion of visible-light-mediated photocrosslinking and its effects on HA degradation, hydrogel stiffness, and endothelial cell behavior. These additions enhance the completeness of the modification strategies and strengthen the connection between chemical design and biological performance.

1. We have added the relevant paragraph on page 7, line 282-298 and highlighted it in red. [Tyramine modification is an important and widely used strategy for HA functionalization...]
2. We have added Table 1. on page 8, line 306 and high lighted it in red. [Table1.Hyaluronic acid crosslinking methods: representative reagents, reaction conditions, advantages and limitations.]

3. Additional clarifications

1. As substantial new content and mechanistic analysis have been incorporated, we have rewritten the Conclusion (page 24, line 749-782) and Abstract (page 1, line 18-34) section to better reflect the revised scope and key messages of the manuscript.

2. We have provided a list of abbreviations (page 25, line 792) to improve readability and consistency throughout the manuscript.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

this review is accepted as it is.

Reviewer 2 Report

Comments and Suggestions for Authors

Authors have carefully met all my comments and revided their manuscript properly.

I recommend acceptance of this paper

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have responded adequately to all reviewer comments, and the revised manuscript demonstrates clear improvement in both scientific clarity and presentation. The previous concerns have been satisfactorily addressed. Therefore, I recommend acceptance of the manuscript in its current form, as it is expected to contribute meaningful insights to the field.