Development, structure, and bioengineering of the human corneal stroma: A review of collagen-based implants

Enhanced Bioprinting of 3D Corneal Stroma Patches with Reliability, Assessing Product Consistency and Quality through Optimized Electron Beam Sterilization

This study focuses on the optimization of sterilization methods for bioprinted three-dimensional (3D) corneal stroma patches prepared using cornea-derived decellularized extracellular matrix (Co-dECM) hydrogels and human keratocytes, with the aim of enhancing clinical applications in corneal tissue engineering. An essential aspect of this study is to refine the sterilization processes, particularly focusing on electron beam (EB) sterilization, to maintain the structural and functional integrity of the Co-dECM hydrogels while ensuring sterility. The study reveals that EB sterilization outperformed traditional methods like ethylene oxide (EtO) gas and autoclaving, which tend to degrade the biochemical properties of hydrogels. By optimizing the EB-sterilization process, the essential mechanical and biochemical characteristics needed for successful 3D bioprinting are retained, reducing batch variability in bioprinted 3D corneal stroma patches. Consistency in production is vital for meeting regulatory standards and ensuring patient safety. Moreover, the study investigates the immunomodulatory properties of sterilized hydrogels, emphasizing their potential to minimize inflammatory responses, which is crucial for maintaining keratocyte phenotype. These findings significantly advance biomedical engineering by providing a sterilization method that preserves material integrity, minimizes immunogenicity, and supports the clinical translation of bioprinted corneal stroma patches, offering a promising alternative to donor transplants and synthetic substitutes.

Decellularization of camel corneas for tissue engineering applications

PURPOSE

The similarity in collagen fiber diameter between the camel cornea (CC) and the human cornea, along with its relatively large size, positions the CC as a promising candidate for tissue engineering applications. This study aimed to evaluate the effectiveness of various decellularization methods on the CC, followed by assessing protein content similarities between the CC and the human cornea, highlighting its potential for human-related tissue engineering research.

METHODS

Camel corneas were extracted from freshly isolated camel eyeballs and subjected to multiple decellularization protocols, including sodium dodecyl sulfate (SDS)-based and formic acid (FA)-based methods. The decellularized camel corneas (dCCs) were then analyzed for histological properties, cell viability, collagen fiber integrity, ultrastructural characteristics, and susceptibility to bacterial contamination. Additionally, the amino acid (AA) composition of CC proteins was compared to that of the human cornea.

RESULTS

Histological analyses confirmed successful decellularization of the CC using both SDS- and FA-based protocols. Cell viability significantly increased when cells were cultured on dCC scaffolds, with the highest improvement observed in the 0.5% SDS-Tris-treated group. OrgA and 0.5% SDS-Tris protocols preserved collagen fibers most effectively among the treatment groups. Ultrastructural assessments revealed consistent results across all groups. However, susceptibility to bacterial contamination was noted in the FA-treated group after one week of refrigerated storage. Lastly, the AA composition of CC proteins demonstrated a notable resemblance to the human cornea.

CONCLUSION

This study demonstrates that the CC can be effectively decellularized using SDS- and FA-based methods while maintaining tissue morphology, ultrastructure, and collagen fiber integrity. Despite FA's efficacy in decellularization, its potential for causing bacterial contamination warrants caution in its application. The high degree of similarity in AA composition between CC and the human cornea further underscores the potential of CC as a scaffold for human-related tissue engineering studies.

Effect of corneal cross-linking on biomechanical properties of swollen rabbit corneas

Corneal cross-linking (CXL) is an effective method to prevent the progression of keratoconus. CXL combined with hypotonic riboflavin solution is a modified treatment for thin corneas, which are deemed to be below the safe thickness threshold. In this study, rabbit corneas were subjected to different hydration levels using different osmolarity of riboflavin dextran solutions before CXL. Inflation testing was performed to evaluate the corneal biomechanical stiffening effect of hypotonic riboflavin solutions crosslinking. One-month post-CXL, the stromal demarcation line depth (DLD) and the biomechanical property parameter - tangent modulus (Et) - were measured. All CXL groups showed higher Et than the corresponding Ctrl groups (all P < 0.001), however, the Et values showed no statistical differences between the CXL-ed groups with different hydration levels (all P > 0.05). The relative depth ratio of DLD to total corneal thickness (TCT) did not show significant differences (P > 0.05), while the DLD was statistically different in three CXL groups (P < 0.001). The research suggested that riboflavin solutions with different osmolarities are suitable for preoperative swelling of corneas with different thickness ranges. Furthermore, crosslinking with hypotonic riboflavin solutions has no significant effect on corneal biomechanical improvement under a certain degree of hydration.

Bio-spectroscopic analysis of corneal structural alterations in dry eye disease: A study of collagen, co-enzymes, lipids, and proteins with emphasis on phytotherapy intervention

Dry eye disease (DED) stands as a prevalent cause for ophthalmology consultations, securing the third position following refractive errors and cataracts. Moreover, the likelihood of experiencing DED escalates with advancing age. In this experimental study corneal tissue alterations due to DED were investigated over different periods by applying both infrared and synchronous fluorescence spectroscopy. The potential effects of instillation of pomegranate and green tea water extracts as green-friendly treatment modalities were also evaluated. The obtained results collectively indicate that DED affects the OH bearing constituents (collagen, glycosaminoglycans, and proteoglycans) of cornea leading to changes in protein secondary structure and the collagen fibrils. Additionally, enhanced dehydrated environment, and reduced energetic/metabolic state, as indicated by co-enzymes, was observed. Phyto-therapeutic administration can contain these alterations with enhanced energetic/metabolic state and increased hydration environment. In conclusion, instillation of green tea extract can protect/restore the collagen fibrils and its potential effects, in general, exceeds that of pomegranate extract.

Harnessing Corneal Stromal Regeneration for Vision Restoration: A Comprehensive Review of the Emerging Treatment Techniques for Keratoconus

Keratoconus is a progressive corneal disorder characterized by thinning and conical protrusion, leading to visual impairment that often necessitates advanced treatment strategies. Traditional management options, including corrective lenses, corneal cross-linking (CXL), and surgical interventions such as corneal transplants and intracorneal ring segments (ICRS), address symptoms but have limitations, especially in progressive or advanced cases. Recent advancements in corneal stromal regeneration offer promising alternatives for enhancing vision restoration and halting disease progression. This review explores emerging techniques focused on corneal stromal regeneration, emphasizing cell-based therapies, tissue engineering, and gene therapy. Cell-based approaches, including corneal stromal stem cells and adipose-derived stem cells, are promising to promote tissue repair and functional recovery. Tissue engineering techniques, such as developing synthetic and biological scaffolds and 3D bioprinting, are being investigated for their ability to create viable corneal grafts and implants. Additionally, gene therapy and molecular strategies, including gene editing technologies and the application of growth factors, are advancing the potential for targeted treatment and regenerative medicine. Despite these advancements, challenges remain, including technical limitations, safety concerns, and ethical considerations. This review aims to provide a comprehensive overview of these innovative approaches, highlighting their current status, clinical outcomes, and future directions in keratoconus management.

Wnt/β-catenin signaling in corneal epithelium development, homeostasis, and pathobiology

The corneal epithelium is located on the most anterior surface of the eyeball and protects against external stimuli. The development of the corneal epithelium and the maintenance of corneal homeostasis are essential for the maintenance of visual acuity. It has been discovered recently via the in-depth investigation of ocular surface illnesses that the Wnt/β-catenin signaling pathway is necessary for the growth and stratification of corneal epithelial cells as well as the control of endothelial cell stability. In addition, the Wnt/β-catenin signaling pathway is directly linked to the development of common corneal illnesses such as keratoconus, fungal keratitis, and corneal neovascularization. This review mainly summarizes the role of the Wnt/β-catenin signaling pathway in the development, homeostasis, and pathobiology of cornea, hoping to provide new insights into the study of corneal epithelium and the treatment of related diseases.

Patterned collagen films loaded with miR-133b@MBG-NH2for potential applications in corneal stromal injury repair

Corneal stromal injury is a common surgical disease. With the development of tissue engineering materials, many artificial corneal scaffolds have been developed to replace allograft corneal transplantation and solve the problem of corneal donor shortage. However, few researchers have paid attention to corneal stromal wound healing. Herein, a nanocomposite of amino modified mesoporous bioactive glass (MBG-NH2) and microRNA-133b (miR-133b) was introduced into the patterned collagen films to achieve corneal stromal injury repair. MBG-NH2nanoparticles as a nano delivery carrier could efficiently load miR-133b and achieve the slow release of miR-133b. The physicochemical properties of collagen films were characterized and found the microgrooved collagen films loaded with miR-133b@MBG-NH2nanoparticles possessed similar swelling properties, optical clarity, and biodegradability to the natural cornea.In vitrocell experiments were also conducted and proved that the patterned collagen films with miR-133b@MBG-NH2possessed good biocompatibility, and miR-133b@MBG-NH2nanoparticles could be significantly uptake by rabbit corneal stromal cells (RCSCs) and have a significant impact on the orientation, proliferation, migration, and gene expression of RCSCs. More importantly, the patterned collagen films with miR-133b@MBG-NH2could effectively promote the migration of RCSCs and accelerate wound healing process, and down-regulate the expression levels ofα-SMA, COL-I, and CTGF genes associated with myofibroblast differentiation of corneal stromal cells, which has a potential application prospect in the repair of corneal stromal injury.

Squishy matters - Corneal mechanobiology in health and disease

The cornea, as a dynamic and responsive tissue, constantly interacts with mechanical forces in order to maintain its structural integrity, barrier function, transparency and refractive power. Cells within the cornea sense and respond to various mechanical forces that fundamentally regulate their morphology and fate in development, homeostasis and pathophysiology. Corneal cells also dynamically regulate their extracellular matrix (ECM) with ensuing cell-ECM crosstalk as the matrix serves as a dynamic signaling reservoir providing biophysical and biochemical cues to corneal cells. Here we provide an overview of mechanotransduction signaling pathways then delve into the recent advances in corneal mechanobiology, focusing on the interplay between mechanical forces and responses of the corneal epithelial, stromal, and endothelial cells. We also identify species-specific differences in corneal biomechanics and mechanotransduction to facilitate identification of optimal animal models to study corneal wound healing, disease, and novel therapeutic interventions. Finally, we identify key knowledge gaps and therapeutic opportunities in corneal mechanobiology that are pressing for the research community to address especially pertinent within the domains of limbal stem cell deficiency, keratoconus and Fuchs' endothelial corneal dystrophy. By furthering our understanding corneal mechanobiology, we can contextualize discoveries regarding corneal diseases as well as innovative treatments for them.

Lenticule addition keratoplasty for the treatment of keratoconus: A systematic review and critical considerations

Keratoconus is a corneal disorder characterized by the progressive thinning and bulging of the cornea. Currently, the major goal of management is to halt its progression, restore normal corneal strength, prevent acute complications, and save vision. Penetrating keratoplasty and deep anterior lamellar keratoplasty as conventional surgical methods for advanced keratoconus are limited by relatively high rates of immune intolerance, slow post-operational recovery, high costs, and shortage of donor corneas. Recently, the development of lenticule addition keratoplasty enables the restoration of corneal thickness simply by implanting a lenticule into the stromal pocket created with the femtosecond laser, which can originate from cadaver corneas or more appealing, be extracted from patients via a small-incision lenticule extraction (SMILE) surgery. As the first systematic review in this field, we critically review publications on lenticule addition keratoplasty and provide our perspectives on its clinical application and the focus of future research.

Corneal stromal regeneration-keratoconus cell therapy: a review

BACKGROUND

Keratoconus is a corneal ectatic disease caused by stromal thinning leading to astigmatism and progressive loss of vision. Loss of the keratocytes and excessive degradation of collagen fibres by matrix metalloproteinases are the molecular signatures of the disease. Despite several limitations, corneal collagen cross-linking and keratoplasty are the most widely used treatment options for keratoconus. In the pursuit of alternative treatment modalities, clinician scientists have explored cell therapy paradigms for treating the condition.

METHODS

Articles pertaining to keratoconus cell therapy with relevant key words were used to search in PubMed, Researchgate, and Google Scholar. The articles were selected based on their relevance, reliability, publication year, published journal, and accessibility.

RESULTS

Various cellular abnormalities have been reported in keratoconus. Diverse cell types such as mesenchymal stromal cells, dental pulp cells, bone marrow stem cells, haematopoietic stem cells, adipose-derived stem cells apart from embryonic and induced pluripotent stem cells can be used for keratoconus cell therapy. The results obtained show that there is a potential for these cells from various sources as a viable treatment option.

CONCLUSION

There is a need for consensus with respect to the source of cells, mode of delivery, stage of disease, and duration of follow-up, to establish a standard operating protocol. This would eventually widen the cell therapy options for corneal ectatic diseases beyond keratoconus.

Electro-compacted collagen for corneal epithelial tissue engineering

Bioengineered corneal substitutes offer a solution to the shortage of donor corneal tissue worldwide. As one of the major structural components of the cornea, collagen has shown great potential for tissue-engineered cornea substitutes. Herein, free-standing collagen membranes fabricated using electro-compaction were assessed in corneal bioengineering application by comparing them with nonelectro-compacted collagen (NECC). The well-organized and biomimetic fibril structure resulted in a significant improvement in mechanical properties. A 10-fold increase in tensile and compressive modulus was recorded when compared with NECC membranes. In addition to comparable transparency in the visible light range, the glucose permeability of the electro-compacted collagen (ECC) membrane is higher than that of the native human cornea. Human corneal epithelial cells adhere and proliferate well on the ECC membrane, with a large cell contact area observed. The as-described ECC has appropriate structural, topographic, mechanical, optical, glucose permeable, and cell support properties to provide a platform for a bioengineered cornea; including the outer corneal epithelium and potentially deeper corneal tissues.

Single-Cell RNA Sequencing: Opportunities and Challenges for Studies on Corneal Biology in Health and Disease

The structure and major cell types of the multi-layer human cornea have been extensively studied. However, various cell states in specific cell types and key genes that define the cell states are not fully understood, hindering our comprehension of corneal homeostasis, related diseases, and therapeutic discovery. Single-cell RNA sequencing is a revolutionary and powerful tool for identifying cell states within tissues such as the cornea. This review provides an overview of current single-cell RNA sequencing studies on the human cornea, highlighting similarities and differences between them, and summarizing the key genes that define corneal cell states reported in these studies. In addition, this review discusses the opportunities and challenges of using single-cell RNA sequencing to study corneal biology in health and disease.

Intracorneal Implantation of 3D Bioprinted Scaffolds Containing Mesenchymal Stromal Cells Using Femtosecond-Laser-Assisted Intrastromal Keratoplasty

Injury of the cornea is a complex biological process. Regeneration of the corneal stroma can be facilitated by the presence of mesenchymal stromal cells (MSCs) and application of tissue equivalents. A new tissue-engineering strategy for corneal stroma regeneration is presented using cellularized 3D bioprinted hydrogel constructs implanted into organ cultured porcine corneas using femtosecond laser-assisted intrastromal keratoplasty. The ex vivo cultured, MSC-loaded 3D bioprinted structures remain intact, support cell survival, and contain de novo synthesized extracellular matrix components and migrating cells throughout the observation period. At day 14 postimplantation, the cellularized tissue equivalents contain few or no cells, as demonstrated by optical coherence tomography imaging and immunofluorescent staining. This study successfully combines a laboratory-based method with modern, patient-care practice to produce a cell-laden tissue equivalent for corneal implantation. Optimal bioink composition and cellularization of tissue equivalents are essential in fine-tuning a method to promote the current technique as a future treatment modality.

A scalable corneal xenograft platform: simultaneous opportunities for tissue engineering and circular economic sustainability by repurposing slaughterhouse waste

Introduction: Corneal disease is a leading cause of blindness globally that stems from various etiologies. High-throughput platforms that can generate substantial quantities of corneal grafts will be invaluable in addressing the existing global demand for keratoplasty. Slaughterhouses generate substantial quantities of underutilized biological waste that can be repurposed to reduce current environmentally unfriendly practices. Such efforts to support sustainability can simultaneously drive the development of bioartificial keratoprostheses. Methods: Scores of discarded eyes from the prominent Arabian sheep breeds in our surrounding region of the United Arab Emirates (UAE) were repurposed to generate native and acellular corneal keratoprostheses. Acellular corneal scaffolds were created using a whole-eye immersion/agitation-based decellularization technique with a widely available, eco-friendly, and inexpensive 4% zwitterionic biosurfactant solution (Ecover, Malle, Belgium). Conventional approaches like DNA quantification, ECM fibril organization, scaffold dimensions, ocular transparency and transmittance, surface tension measurements, and Fourier-transform infrared (FTIR) spectroscopy were used to examine corneal scaffold composition. Results: Using this high-throughput system, we effectively removed over 95% of the native DNA from native corneas while retaining the innate microarchitecture that supported substantial light transmission (over 70%) after reversing opacity, a well-established hallmark of decellularization and long-term native corneal storage, with glycerol. FTIR data revealed the absence of spectral peaks in the frequency range 2849 cm-1 to 3075 cm-1, indicating the effective removal of the residual biosurfactant post-decellularization. Surface tension studies confirmed the FTIR data by capturing the surfactant's progressive and effectual removal through tension measurements ranging from approximately 35 mN/m for the 4% decellularizing agent to 70 mN/m for elutes highlighting the effective removal of the detergent. Discussion: To our knowledge, this is the first dataset to be generated outlining a platform that can produce dozens of ovine acellular corneal scaffolds that effectively preserve ocular transparency, transmittance, and ECM components using an eco-friendly surfactant. Analogously, decellularization technologies can support corneal regeneration with attributes comparable to native xenografts. Thus, this study presents a simplified, inexpensive, and scalable high-throughput corneal xenograft platform to support tissue engineering, regenerative medicine, and circular economic sustainability.

Loss of aquaporin 5 contributes to the corneal epithelial pathogenesis via Wnt/β-catenin pathway

AQP5 plays a crucial role in maintaining corneal transparency and the barrier function of the cornea. Here, we found that in the corneas of Aqp5-/- mice at older than 6 months, loss of AQP5 significantly increased corneal neovascularization, inflammatory cell infiltration, and corneal haze. The results of immunofluorescence staining showed that upregulation of K1, K10, and K14, and downregulation of K12 and Pax6 were detected in Aqp5-/- cornea and primary corneal epithelial cells. Loss of AQP5 aggravated wound-induced corneal neovascularization, inflammation, and haze. mRNA sequencing, western blotting, and qRT-PCR showed that Wnt2 and Wnt6 were significantly decreased in Aqp5-/- corneas and primary corneal epithelial cells, accompanied by decreased aggregation in the cytoplasm and nucleus of β-catenin. IIIC3 significantly suppressed corneal neovascularization, inflammation, haze, and maintained corneal transparent epithelial in Aqp5-/- corneas. We also found that pre-stimulated Aqp5-/- primary corneal epithelial cells with IIIC3 caused the decreased expression of K1, K10, and K14, the increased expression of K12, Pax6, and increased aggregation in the cytoplasm and nucleus of β-catenin. These findings revealed that AQP5 may regulate corneal epithelial homeostasis and function through the Wnt/β-catenin signaling pathway. Together, we uncovered a possible role of AQP5 in determining corneal epithelial cell fate and providing a potential therapeutic target for corneal epithelial dysfunction.

Effects of Different Radiation Sources on the Performance of Collagen-Based Corneal Repair Materials and Macrophage Polarization

Owing to the lack of donor corneas, there is an urgent need for suitable corneal substitutes. As the main component of the corneal stroma, collagen has great advantages as a corneal repair material. If there are microorganisms such as bacteria in the corneal repair material, it may induce postoperative infection, causing the failure of corneal transplantation. Therefore, irradiation, as a common sterilization method, is often used to control the microorganisms in the material. However, it has not been reported which type of radiation source and what doses can sterilize more effectively without affecting the properties of collagen-based corneal repair materials (CCRMs) and have a positive impact on macrophage polarization. In this study, three different radiation sources of ultraviolet, cobalt-60, and electron beam at four different doses of 2, 5, 8, and 10 kGy were used to irradiate CCRMs. The swelling, stretching, transmittance, and degradation of the irradiated CCRMs were characterized, and the proliferation of human corneal epithelial cells on the irradiated CCRMs was characterized using the CCK8 kit. The results showed that low dose (<5 kGy) of radiation had little effect on the performance of CCRMs. Three irradiation methods with less influence were selected for the further study on RAW264.7 macrophage polarization. The results indicated that CCRMs treated with UV could downregulate the expression of pro-inflammatory related genes and upregulate the expression of anti-inflammatory genes in macrophages, which indicated that UV irradiation is a beneficial process for the preparation of CCRMs.

[Modern prerequisites for creating a collagen-based artificial analogue of the corneal stroma]

Despite the fact that various collagen biomaterials have been actively used in ophthalmology for more than 30 years, the problem of creating a material that could replace the donor cornea have not been solved. Recent advances in the field of tissue engineering and regenerative medicine have shifted the focus of approaches to solving the problem of creating an artificial cornea towards laying conditions for the restoration of its specific layers through mechanisms of its own cellular regeneration. In this regard, extracellular matrices based on collagen are gaining popularity. This review discusses general limitations and advantages of collagen for creating an artificial cornea.

Melt electro-written scaffolds with box-architecture support orthogonally oriented collagen

Melt electro-writing (MEW) is a state-of-the-art technique that supports fabrication of 3D, precisely controlled and reproducible fiber structures. A standard MEW scaffold design is a box-structure, where a repeat layer of 90° boxes is produced from a single fiber. In 3D form (i.e. multiple layers), this structure has the potential to mimic orthogonal arrangements of collagen, as observed in the corneal stroma. In this study, we determined the response of human primary corneal stromal cells and their deposited fibrillar collagen (detected using a CNA35 probe) following six weeksin vitroculture on these box-structures made from poly(ϵ-caprolactone) (PCL). Comparison was also made to glass substrates (topography-free) and electrospun PCL fibers (aligned topography). Cell orientation and collagen deposition were non-uniform on glass substrates. Electrospun scaffolds supported an excellent parallel arrangement of cells and deposited collagen to the underlying architecture of aligned fibers, but there was no evidence of bidirectional collagen. In contrast, MEW scaffolds encouraged the formation of a dense, interconnected cellular network and deposited fibrillar collagen layers with a distinct orthogonal-arrangement. Collagen fibrils were particularly dominant through the middle layers of the MEW scaffolds' total thickness and closer examination revealed these fibrils to be concentrated within the pores' central regions. With the demand for donor corneas far exceeding the supply-leaving many with visual impairment-the application of MEW as a potential technique to recreate the corneal stroma with spontaneous, bidirectional collagen organization warrants further study.

Generation of a Biomimetic Substitute of the Corneal Limbus Using Decellularized Scaffolds

Patients with severe limbal damage and limbal stem cell deficiency are a therapeutic challenge. We evaluated four decellularization protocols applied to the full-thickness and half-thickness porcine limbus, and we used two cell types to recellularize the decellularized limbi. The results demonstrated that all protocols achieved efficient decellularization. However, the method that best preserved the transparency and composition of the limbus extracellular matrix was the use of 0.1% SDS applied to the half-thickness limbus. Recellularization with the limbal epithelial cell line SIRC and human adipose-derived mesenchymal stem cells (hADSCs) was able to generate a stratified epithelium able to express the limbal markers p63, pancytokeratin, and crystallin Z from day 7 in the case of SIRC and after 14-21 days of induction when hADSCs were used. Laminin and collagen IV expression was detected at the basal lamina of both cell types at days 14 and 21 of follow-up. Compared with control native limbi, tissues recellularized with SIRC showed adequate picrosirius red and alcian blue staining intensity, whereas limbi containing hADSCs showed normal collagen staining intensity. These preliminary results suggested that the limbal substitutes generated in this work share important similarities with the native limbus and could be potentially useful in the future.

Application of marine collagen for stem-cell-based therapy and tissue regeneration (Review)

Tissue engineering and regenerative medicine is becoming an important component in modern biological scientific research. Tissue engineering, a branch of regenerative medicine, is a field that is actively developing to meet the challenges presented in biomedical applications. This particularly applies to the research area of stem cells and biomaterials, due to both being pivotal determinants for the successful restoration or regeneration of damaged tissues and organs. Recently, the development of innovative marine collagen-based biomaterials has attracted attention due to the reported environmentally friendly properties, the lack of zoonotic disease transmission, biocompatibility, bioactivity, the lack of ethics-related concerns and cost-effectiveness for manufacturing. The present review aimed to summarize the potential application and function of marine collagen in stem cell research in a medical and clinical setting. In addition, the present review cited recent studies regarding the latest research advances into using marine collagen for cartilage, bone, periodontal and corneal regeneration. It also characterized the distinct advantages of using marine collagen for stem cell-based tissue repair and regeneration. In addition, the present review comprehensively discussed the most up to date information on stem cell biology, particularly the possibility of treating stem cells with marine collagen to maximize their multi-directional differentiation capability, which highlights the potential use of marine collagen in regenerative medicine. Furthermore, recent research progress on the potential immunomodulatory capacity of mesenchymal stem cells following treatment with marine collagen to improve the understanding of cell-matrix interactions was investigated. Finally, perspectives on the possible future research directions for the application of marine collagen in the area of regenerative medicine are provided.