New Insight into Natural Extracellular Matrix: Genipin Cross-Linked Adipose-Derived Stem Cell Extracellular Matrix Gel for Tissue Engineering

Engineering cell-derived extracellular matrix for peripheral nerve regeneration

Extracellular matrices (ECMs) play a key role in nerve repair and are recognized as the natural source of biomaterials. In parallel to extensively studied tissue-derived ECMs (ts-ECMs), cell-derived ECMs (cd-ECMs) also have the capability to partially recapitulate the complicated regenerative microenvironment of native nerve tissues. Notably, cd-ECMs can avoid the shortcomings of ts-ECMs. Cd-ECMs can be prepared by culturing various cells or even autologous cells in vitro under pathogen-free conditions. And mild decellularization can achieve efficient removal of immunogenic components in cd-ECMs. Moreover, cd-ECMs are more readily customizable to achieve the desired functional properties. These advantages have garnered significant attention for the potential of cd-ECMs in neuroregenerative medicine. As promising biomaterials, cd-ECMs bring new hope for the effective treatment of peripheral nerve injuries. Herein, this review comprehensively examines current knowledge about the functional characteristics of cd-ECMs and their mechanisms of interaction with cells in nerve regeneration, with a particular focus on the preparation, engineering optimization, and scalability of cd-ECMs. The applications of cd-ECMs from distinct cell sources reported in peripheral nerve tissue engineering are highlighted and summarized. Furthermore, current limitations that should be addressed and outlooks related to clinical translation are put forward as well.

Tendon extracellular-matrix-derived tissue engineering micro-tissue for Achilles tendon injury regeneration in rats

BACKGROUND

Achilles tendon is vital in maintaining the stability and function of ankle joint. It is quite difficult to achieve the structural and functional repair of Achilles tendon in tissue engineering.

METHODS

A tissue-engineered tendon micro-tissue was prepared using rat tail tendon extracellular matrix (TECM) combined with rat adipose stem cells (ADSCs) to repair Achilles tendon injuries. The TECM was prepared by repeated freezing and thawing. The in vitro characteristics of TECM and its effect on ADSCs proliferation were detected. This tissue-engineered tendon micro-tissue for Achilles tendon repair in vivo was evaluated based on general characteristics, gait analysis, ultrasound findings, histological analysis, and biomechanical testing.

RESULTS

The results showed that the TECM scaffold had good biocompatibility for ADSCs. At 2 weeks post-surgery, collagen types I and III and tenomodulin expression were higher, and vascular endothelial growth factor expression was lower in the micro-tissue group than other groups. At 4 and 8 weeks post-surgery, the results of histological analysis and ultrasound findings showed that the repaired tendon tissue was smooth and lustrous, and was arranged regularly and evenly in the micro-tissue group. Gait analysis confirmed that better motor function recovery was noted in micro-tissue group than other groups. In addition, the mechanical properties of the repaired tendon tissue in micro-tissue group were better than other groups.

CONCLUSION

Tissue-engineered tendon micro-tissue fabricated by TECM and ADSCs has good biocompatibility and can promote structural and functional repair of tendon in vivo. This composite biomaterial has broad application prospects in tissue engineering.

Tissue-specific gelatin bioink as a rheology modifier for high printability and adjustable tissue properties

Decellularized extracellular matrix (dECM) has emerged as an exceptional biomaterial that effectively recapitulates the native tissue microenvironment for enhanced regenerative potential. Although various dECM bioinks derived from different tissues have shown promising results, challenges persist in achieving high-resolution printing of flexible tissue constructs because of the inherent limitations of dECM's weak mechanical properties and poor printability. Attempts to enhance mechanical rigidity through chemical modifications, photoinitiators, and nanomaterial reinforcement have often compromised the bioactivity of dECM and mismatched the desired mechanical properties of target tissues. In response, this study proposes a novel method involving a tissue-specific rheological modifier, gelatinized dECM. This modifier autonomously enhances bioink modulus pre-printing, ensuring immediate and precise shape formation upon extrusion. The hybrid bioink with GeldECM undergoes a triple crosslinking system-physical entanglement for pre-printing, visible light photocrosslinking during printing for increased efficiency, and thermal crosslinking post-printing during tissue culture. A meticulous gelatinization process preserves the dECM protein components, and optimal hybrid ratios modify the mechanical properties, tailoring them to specific tissues. The application of this sequential multiple crosslinking designs successfully yielded soft yet resilient tissue constructs capable of withstanding vigorous agitation with high shape fidelity. This innovative method, founded on mechanical modulation by GeldECM, holds promise for the fabrication of flexible tissues with high resilience.

Modulation of Decellularized Lacrimal Gland Hydrogel Biodegradation by Genipin Crosslinking

Purpose

Hydrogels derived from decellularized tissues are promising biomaterials in tissue engineering, but their rapid biodegradation can hinder in vitro cultivation. This study aimed to retard biodegradation of a hydrogel derived from porcine decellularized lacrimal glands (dLG-HG) by crosslinking with genipin to increase the mechanical stability without affecting the function and viability of lacrimal gland (LG)-associated cells.

Methods

The effect of different genipin concentrations on dLG-HG stiffness was measured rheologically. Cell-dependent biodegradation was quantified over 10 days, and the impact on matrix metalloproteinase (MMP) activity was quantified by gelatin and collagen zymography. The viability of LG epithelial cells (EpCs), mesenchymal stem cells (MSCs), and endothelial cells (ECs) cultured on genipin-crosslinked dLG-HG was assessed after 10 days, and EpC secretory activity was analyzed by β-hexosaminidase assay.

Results

The 0.5-mM genipin increased the stiffness of dLG-HG by about 46%, and concentrations > 0.25 mM caused delayed cell-dependent biodegradation and reduced MMP activity. The viability of EpCs, MSCs, and ECs was not affected by genipin concentrations of up to 0.5 mM after 10 days. Moreover, up to 0.5-mM genipin did not negatively affect EpC secretory activity compared to control groups.

Conclusions

A concentration of 0.5-mM genipin increased dLG-HG stiffness, and 0.25-mM genipin was sufficient to prevent MMP-dependent degradation. Importantly, concentrations of up to 0.5-mM genipin did not compromise the viability of LG-associated cells or the secretory activity of EpCs. Thus, crosslinking with genipin improves the properties of dLG-HG for use as a substrate in LG tissue engineering.

Crosslinking strategies of decellularized extracellular matrix in tissue regeneration

By removing the immunogenic cellular components through various decellularization methods, decellularized extracellular matrix (dECM) is considered a promising material in the field of tissue engineering and regenerative medicine with highly preserved physicochemical properties and superior biocompatibility. However, decellularization treatment can lead to some loss of structural integrity, mechanical strength, degradation stability, and biological performance of dECM biomaterials. Therefore, physical and chemical crosslinking methods are preferred to restore or even improve the biomechanical properties, stability, and bioactivity, and to achieve a delicate balance between degradation of the implanted biomaterial and regeneration of the host tissue. This review provides an overview of dECM biomaterials, and describes and compares the mechanisms and characteristics of commonly used crosslinking methods for dECM, with a focus on the potential applications of versatile dECM-based biomaterials derived from skin, cardiac tissues (pericardium, heart valves, myocardial tissue), blood vessels, liver, and kidney, modified with different chemical crosslinking reagents, in tissue and organ regeneration.

The role of decellularized cell derived extracellular matrix in the establishment and culture ofin vitrobreast cancer tumor model

Decades of research have shown that two-dimensional cell culture studies are insufficient for preclinical cancer diagnosis and treatment, and that cancer cells in three-dimensional (3D) culture systems have better cell-cell and cell-matrix interactions, gene expression, heterogeneity, and structural complexity that more closely resemblein vivotumors. Researchers are still optimizing 3D culturing settings for different cancers. Despite promising tumor spheroid research, tumor cell-only aggregates lack the tumor microenvironment and cannot model tumors. Here, MCF-7 breast cancer cell derived decellularized extracellular matrix (CD-dECMs) were obtained and converted into autologous, biologically active, biocompatible, and non-immunogenic hydrogels to be used as micro-environment in both organoid formation and culture. For the production of organoids, CD-dECM doping concentrations ranging from 0.1 mg ml-1to 1.5 mg ml-1were evaluated, and the lowest concentration was found to be the most effective. For organoid culture, 8 mg ml-1CD-dECM, 4 mg ml-1rat tendon collagen type I (Col I) (4 mg ml-1) and a 1:1 (v/v) mixture of these two were used and the most viable and the biggest organoids were discovered in CD-dECM/Col I (1:1) group. The results show that autologous CD-dECM can replace hydrogels in tumor organoid generation and culture at low and high concentrations, respectively.

Adipose stem cells in tissue regeneration and repair: From bench to bedside

ADSCs are a large number of mesenchymal stem cells in Adipose tissue, which can be applied to tissue engineering. ADSCs have the potential of multi-directional differentiation, and can differentiate into bone tissue, cardiac tissue, urothelial cells, skin tissue, etc. Compared with other mesenchymal stem cells, ADSCs have a multitude of promising advantages, such as abundant number, accessibility in cell culture, stable function, and less immune rejection. There are two main methods to use ADSCs for tissue repair and regeneration. One is to implant the "ADSCs-scaffold composite" into the injured site to promote tissue regeneration. The other is cell-free therapy: using ADSC-exos or ADSC-CM alone to release a large number of miRNAs, cytokines and other bioactive substances to promote tissue regeneration. The tissue regeneration potential of ADSCs is regulated by a variety of cytokines, signaling molecules, and external environment. The differentiation of ADSCs into different tissues is also induced by growth factors, ions, hormones, scaffold materials, physical stimulation, and other factors. The specific mechanisms are complex, and most of the signaling pathways need to be further explored. This article reviews and summarizes the mechanism and clinical application of ADSCs in tissue injury repair so far, and puts forward further problems that need to be solved in this field, hoping to provide directions for further research in this field.

Cryosectioning of Hydrogels as a Reliable Approach to Increase Yield and Further Tune Mechanical Properties

Decellularized extracellular matrix (dECM) hydrogels have emerged as promising materials in tissue engineering. The steps to produce dECM hydrogels containing the bioactive epitopes found in the native matrix are often laborious, including the initial harvesting and decellularization of the animal organ. Furthermore, resulting hydrogels often exhibit weak mechanical properties that require the use of additional crosslinkers such as genipin to truly simulate the mechanical properties of the desired study tissue. In this work, we have developed a protocol to readily obtain tens of thin dECM hydrogel cryosections attached to a glass slide as support, to serve as scaffolds for two-dimensional (2D) or three-dimensional (3D) cell culture. Following extensive atomic force microscopy (AFM)-based mechanical characterization of dECM hydrogels crosslinked with increasing genipin concentrations (5 mM, 10 mM, and 20 mM), we provide detailed protocol recommendations for achieving dECM hydrogels of any biologically relevant stiffness. Given that our protocol requires hydrogel freezing, we also confirm that the approach taken can be further used to increase the mechanical properties of the scaffold in a controlled manner exhibiting twice the stiffness in highly crosslinked arrays. Finally, we explored the effect of ethanol-based short- and long-term sterilization on dECM hydrogels, showing that in some situations it may give rise to significant changes in hydrogel mechanical properties that need to be taken into account in experimental design. The hydrogel cryosections produced were shown to be biocompatible and support cell attachment and spreading for at least 72 h in culture. In brief, our proposed method may provide several advantages for tissue engineering: (1) easy availability and reduction in preparation time, (2) increase in the total hydrogel volume eventually used for experiments being able to obtain 15-22 slides from a 250 µL hydrogel) with a (3) reduction in scaffold variability (only a 17.5 ± 9.5% intraslide variability provided by the method), and (4) compatibility with live-cell imaging techniques or further cell characterization of cells.

Combining decellularized adipose tissue with decellularized adventitia extravascular matrix or small intestinal submucosa matrix for the construction of vascularized tissue-engineered adipose

Adipose tissue is an endocrine organ. It serves many important functions, such as energy storage, hormones secretion, and providing insulation, cushioning and aesthetics to the body etc. Adipose tissue engineering offers a promising treatment for soft tissue defects. Early adipose tissue production and long-term survival are closely associated with angiogenesis. Decellularized matrix has a natural ECM (extracellular matrix) component, good biocompatibility, and low immunogenicity. Therefore, in this study, the injectable composite hydrogels were developed to construct vascularized tissue-engineered adipose by using the pro-angiogenic effects of aortic adventitia extravascular matrix (Adv) or small intestinal submucosa (SIS), and the pro-adipogenic effects of decellularized adipose tissue (DAT). The composite hydrogels were cross-linked by genipin. The adipogenic and angiogenic abilities of composite hydrogels were investigated in vitro, and in a rat dorsal subcutaneous implant model. The results showed that DAT and SIS or Adv 1:1 composite hydrogel promoted the migration and tube formation of endothelial cells. Furthermore, DAT and SIS or Adv 1:1 composite hydrogel enhanced adipogenic differentiation of adipose-derived mesenchymal stem cells (ASCs) through activation of PPARγ and C/EBPα. The in vivo studies further demonstrated that DAT with SIS or Adv in a 1:1 ratio also significantly promoted adipogenesis and angiogenesis. In addition, DAT with SIS or Adv in a 1:1 ratio hydrogel recruited macrophage population with enhanced M2-type macrophage polarization, suggesting a positive effect of inflammatory response on angiogenesis. In conclusion, these data suggest that the composite hydrogels of DAT with SIS or Adv in 1:1 ratio have apparent pro-adiogenic and angiogenic abilities, thus providing a promising cell-free tissue engineering biomaterial with broad clinical applications. STATEMENT OF SIGNIFICANCE: Decellularized adipose tissue (DAT) has emerged as an important biomaterial in adipose tissue regeneration. Early adipose tissue production and long-term survival is tightly related to the angiogenesis. The revascularization of the DAT is a key issue that needs to be solved in adipose regeneration. In this study, the injectable composite hydrogels were developed by using DAT with Adv (aortic adventitia extravascular matrix) or SIS (small intestinal submucosa) in different ratio. We demonstrated that the combination of DAT with SIS or Adv in 1:1 ratio effectively improved the proliferation of adipose stem cells and endothelial cells, and promoted greater adipose regeneration and tissue vascularization as compared to the DAT scaffold. This study provides the potential biomaterial for clinical soft tissue regeneration.

Preparation and Use of Decellularized Extracellular Matrix for Tissue Engineering

The multidisciplinary fields of tissue engineering and regenerative medicine have the potential to revolutionize the practise of medicine through the abilities to repair, regenerate, or replace tissues and organs with functional engineered constructs. To this end, tissue engineering combines scaffolding materials with cells and biologically active molecules into constructs with the appropriate structures and properties for tissue/organ regeneration, where scaffolding materials and biomolecules are the keys to mimic the native extracellular matrix (ECM). For this, one emerging way is to decellularize the native ECM into the materials suitable for, directly or in combination with other materials, creating functional constructs. Over the past decade, decellularized ECM (or dECM) has greatly facilitated the advance of tissue engineering and regenerative medicine, while being challenged in many ways. This article reviews the recent development of dECM for tissue engineering and regenerative medicine, with a focus on the preparation of dECM along with its influence on cell culture, the modification of dECM for use as a scaffolding material, and the novel techniques and emerging trends in processing dECM into functional constructs. We highlight the success of dECM and constructs in the in vitro, in vivo, and clinical applications and further identify the key issues and challenges involved, along with a discussion of future research directions.

Perfusion decellularization for vascularized composite allotransplantation

Vascularized composite allotransplantation is becoming the emerging standard for reconstructive surgery treatment for patients with limb trauma and facial injuries involving soft tissue loss. Due to the complex immunogenicity of composite grafts, patients who undergo vascularized composite allotransplantation are reliant on lifelong immunosuppressive therapy. Decellularization of donor grafts to create an extracellular matrix bio-scaffold provides an immunomodulatory graft that preserves the structural and bioactive function of the extracellular matrix. Retention of extracellular matrix proteins, growth factors, and signaling cascades allow for cell adhesion, migration, proliferation, and tissue regeneration. Perfusion decellularization of detergents through the graft vasculature allows for increased regent access to all tissue layers, and removal of cellular debris through the venous system. Grafts can subsequently be repopulated with appropriate cells through the vasculature to facilitate tissue regeneration. The present work reviews methods of decellularization, process parameters, evaluation of adequate cellular and nuclear removal, successful applications of perfusion decellularization for use in vascularized composite allotransplantation, and current limitations.

Adipose-Derived Stem Cell Sheets Promote Meniscus Regeneration Regardless of Whether the Defect Involves the Inner Half or the Whole Width of the Anterior Half of the Medial Meniscus in a Rabbit Model

PURPOSE

To investigate the regenerative effect of adipose-derived stem cell (ADSC) sheets in two different rabbit models of meniscal defects.

METHODS

Forty-two rabbits were randomly divided into two groups: the whole (Group 1) or the inner half (Group 2) of anterior half of the medial meniscus was removed from both knees. The ADSC sheets were transplanted into one knee, whereas in the other knee the meniscal defect was left untreated (self-control). The histological score and expression of genes encoding collagen type I and II (COL1/2), SRY-box transcription factor 9 (SOX9), and aggrecan (ACAN) were compared between the ADSC sheet-treated and untreated menisci at 4 and 12 weeks. The ADSC sheet-treated menisci at 12 weeks were also analyzed immunohistochemically to assess the collagen component.

RESULTS

The histological score was significantly higher in the treated side than in the control side at 4 and 12 weeks in both groups (Group 1; P = .016 and .032; Group 2; P = .030 and .016, respectively). All genes evaluated showed significantly higher expression in the treated side than in the control side in both groups, except COL2 and SOX9 at 4 weeks and COL2 at 12 weeks in Group 1, and COL1 in Group 2 at 4 weeks. The ADSC sheet-treated meniscus in Group 1 contained mostly COL1, whereas the Group 2 had less COL1, but was rich in COL2.

CONCLUSIONS

ADSC sheets can promote meniscal regeneration regardless of whether the defect involves the inner half or whole width of the anterior half of the medial meniscus. However, the collagen component of the ADSC sheet-treated tissue differs depending on the defect site.

CLINICAL RELEVANCE

ADSCs may help meniscal regeneration due to meniscal defects after meniscectomy. This study suggests longer-term follow-up and mechanical analysis as next steps.

Genipin-Crosslinking Effects on Biomatrix Development for Cutaneous Wound Healing: A Concise Review

Split skin graft (SSG), a standard gold treatment for wound healing, has numerous limitations such as lack of fresh skin to be applied, tedious process, severe scarring, and keloid formation followed by higher risks of infection. Thus, there is a gap in producing polymeric scaffolds as an alternative for wound care management. Bioscaffold is the main component in tissue engineering technology that provides porous three-dimensional (3D) microarchitecture for cells to survive. Upon skin tissue reconstruction, the 3D-porous structure ensures sufficient nutrients and gaseous diffusion and cell penetration that improves cell proliferation and vascularization for tissue regeneration. Hence, it is highly considered a promising candidate for various skin wound healing applications. To date, natural-based crosslinking agents have been extensively used to tailor the physicochemical and mechanical properties of the skin biomatrix. Genipin (GNP) is preferable to other plant-based crosslinkers due to its biological activities, such as antiinflammatory and antioxidant, which are key players to boost skin wound healing. In addition, it has shown a noncytotoxic effect and is biocompatible with human skin cells. This review validated the effects of GNP in biomatrix fabrication for skin wound healing from the last 7 years of established research articles and stipulated the biomaterial development-scale point of view. Lastly, the possible role of GNP in the skin wound healing cascade is also discussed. Through the literature output, it can be concluded that GNP has the capability to increase the stability of biomatrix and maintain the skin cells viability, which will contribute in accelerating wound healing.

Constructing a highly bioactive tendon-regenerative scaffold by surface modification of tissue-specific stem cell derived extracellular matrix

Developing highly bioactive scaffold materials to promote stem cell migration, proliferation and tissue-specific differentiation is a crucial requirement in current tissue engineering and regenerative medicine. Our previous work has demonstrated that the decellularized tendon slices (DTSs) are able to promote stem cell proliferation and tenogenic differentiation in vitro and show certain pro-regenerative capacity for rotator cuff tendon regeneration in vivo. In this study, we present a strategy to further improve the bioactivity of the DTSs for constructing a novel highly bioactive tendon-regenerative scaffold by surface modification of tendon-specific stem cell-derived extracellular matrix (tECM), which is expected to greatly enhance the capacity of scaffold material in regulating stem cell behavior, including migration, proliferation and tenogenic differentiation. We prove that the modification of tECM could change the highly aligned surface topographical cues of the DTSs, retain the surface stiffness of the DTSs and significantly increase the content of multiple ECM components in the tECM-DTSs. As a result, the tECM-DTSs dramatically enhance the migration, proliferation as well as tenogenic differentiation of rat bone marrow-derived stem cells compared with the DTSs. Collectively, this strategy would provide a new way for constructing ECM-based biomaterials with enhanced bioactivity for in situ tendon regeneration applications.

Sources, Characteristics, and Therapeutic Applications of Mesenchymal Cells in Tissue Engineering

Tissue engineering (TE) is a therapeutic option within regenerative medicine that allows to mimic the original cell environment and functional organization of the cell types necessary for the recovery or regeneration of damaged tissue using cell sources, scaffolds, and bioreactors. Among the cell sources, the utilization of mesenchymal cells (MSCs) has gained great interest because these multipotent cells are capable of differentiating into diverse tissues, in addition to their self-renewal capacity to maintain their cell population, thus representing a therapeutic alternative for those diseases that can only be controlled with palliative treatments. This review aimed to summarize the state of the art of the main sources of MSCs as well as particular characteristics of each subtype and applications of MSCs in TE in seven different areas (neural, osseous, epithelial, cartilage, osteochondral, muscle, and cardiac) with a systemic revision of advances made in the last 10 years. It was observed that bone marrow-derived MSCs are the principal type of MSCs used in TE, and the most commonly employed techniques for MSCs characterization are immunodetection techniques. Moreover, the utilization of natural biomaterials is higher (41.96%) than that of synthetic biomaterials (18.75%) for the construction of the scaffolds in which cells are seeded. Further, this review shows alternatives of MSCs derived from other tissues and diverse strategies that can improve this area of regenerative medicine.

Construction of multifunctional porcine acellular dermal matrix hydrogel blended with vancomycin for hemorrhage control, antibacterial action, and tissue repair in infected trauma wounds

Prevention of bacterial infection and reduction of hemorrhage, the primary challenges posed by trauma before hospitalization, are essential steps in prolonging the patient's life until they have been transported to a trauma center. Extracellular matrix (ECM) hydrogel is a promising biocompatible material for accelerating wound closure. However, due to the lack of antibacterial properties, this hydrogel is difficult to be applied to acute contaminated wounds. This study formulates an injectable dermal extracellular matrix hydrogel (porcine acellular dermal matrix (ADM)) as a scaffold for skin defect repair. The hydrogel combines vancomycin, an antimicrobial agent for inducing hemostasis, expediting antimicrobial activity, and promoting tissue repair. The hydrogel possesses a porous structure beneficial for the adsorption of vancomycin. The antimicrobial agent can be timely released from the hydrogel within an hour, which is less than the time taken by bacteria to infest an injury, with a cumulative release rate of approximately 80%, and thus enables a relatively fast bactericidal effect. The cytotoxicity investigation demonstrates the biocompatibility of the ADM hydrogel. Dynamic coagulation experiments reveal accelerated blood coagulation by the hydrogel. In vivo antibacterial and hemostatic experiments on a rat model indicate the healing of infected tissue and effective control of hemorrhaging by the hydrogel. Therefore, the vancomycin-loaded ADM hydrogel will be a viable biomaterial for controlling hemorrhage and preventing bacterial infections in trauma patients.

Collagen Bioinks for Bioprinting: A Systematic Review of Hydrogel Properties, Bioprinting Parameters, Protocols, and Bioprinted Structure Characteristics

Bioprinting is a modern tool suitable for creating cell scaffolds and tissue or organ carriers from polymers that mimic tissue properties and create a natural environment for cell development. A wide range of polymers, both natural and synthetic, are used, including extracellular matrix and collagen-based polymers. Bioprinting technologies, based on syringe deposition or laser technologies, are optimal tools for creating precise constructs precisely from the combination of collagen hydrogel and cells. This review describes the different stages of bioprinting, from the extraction of collagen hydrogels and bioink preparation, over the parameters of the printing itself, to the final testing of the constructs. This study mainly focuses on the use of physically crosslinked high-concentrated collagen hydrogels, which represents the optimal way to create a biocompatible 3D construct with sufficient stiffness. The cell viability in these gels is mainly influenced by the composition of the bioink and the parameters of the bioprinting process itself (temperature, pressure, cell density, etc.). In addition, a detailed table is included that lists the bioprinting parameters and composition of custom bioinks from current studies focusing on printing collagen gels without the addition of other polymers. Last but not least, our work also tries to refute the often-mentioned fact that highly concentrated collagen hydrogel is not suitable for 3D bioprinting and cell growth and development.

Porcine Decellularized Diaphragm Hydrogel: A New Option for Skeletal Muscle Malformations

Hydrogels are biomaterials that, thanks to their unique hydrophilic and biomimetic characteristics, are used to support cell growth and attachment and promote tissue regeneration. The use of decellularized extracellular matrix (dECM) from different tissues or organs significantly demonstrated to be far superior to other types of hydrogel since it recapitulates the native tissue’s ECM composition and bioactivity. Different muscle injuries and malformations require the application of patches or fillers to replenish the defect and boost tissue regeneration. Herein, we develop, produce, and characterize a porcine diaphragmatic dECM-derived hydrogel for diaphragmatic applications. We obtain a tissue-specific biomaterial able to mimic the complex structure of skeletal muscle ECM; we characterize hydrogel properties in terms of biomechanical properties, biocompatibility, and adaptability for in vivo applications. Lastly, we demonstrate that dECM-derived hydrogel obtained from porcine diaphragms can represent a useful biological product for diaphragmatic muscle defect repair when used as relevant acellular stand-alone patch.

Modular mucopolysaccharide gelatin naturapolyceutics hydrocolloid biomatrix with cobalt nano-additives for high density vascular network assembly

The present study demonstrates the development of polysaccharide gelatin naturapolyceutics hydrocolloidal biomatrix with cobalt nano-additives for restructuring native tissue vasculature for tissue regenerative applications. The engineered Gelatin/Aloevera mucilage polysaccharide/nanoscaled Cobalt (GAC) hydrocolloids resulted from the intermolecular interactions between the aloevera mucilage, cobalt nano-therapeutic and gelatin. GAC hydrocolloid showed enhanced thermal stability in comparison with control Gelatin/Aloevera mucilage (GA) hydrocolloid. FTIR analysis validated that the reinforcement of aloevera mucilage and cobalt nano-therapeutic did not affect the structural integrity of the gelatin molecule. 3-Dimensional sponge-like orientation of GAC hydrocolloid facilitates perfusable biomatrix for access to nutrients and gaseous exchange for high cell adhesion and proliferation. The combined therapeutic efficacy of mucilage polysaccharides, biodegradable nanoscaled cobalt and bio-polymer enhanced the pro-angiogenic capability of the hydrocolloids by stimulating Vascular Endothelial Growth Factor (VEGF) response at wounded tissue for faster healing. The experimental outcomes on in vivo angiogenesis profiling further confirmed the development of micro vessel in chick embryonic model and regeneration of blood vessels in zebra fish model. This study opens up the potential of mucilage polysaccharides in stimulating high density angiogenesis and conveys the progress of a biocompatible, biodegradable mucilaginous hydrocolloid as an effective bio-adhesive for vascular development in soft tissue regeneration.

Cell-Derived Extracellular Matrix for Tissue Engineering and Regenerative Medicine

Cell-derived extracellular matrices (CD-ECMs) captured increasing attention since the first studies in the 1980s. The biological resemblance of CD-ECMs to their in vivo counterparts and natural complexity provide them with a prevailing bioactivity. CD-ECMs offer the opportunity to produce microenvironments with costumizable biological and biophysical properties in a controlled setting. As a result, CD-ECMs can improve cellular functions such as stemness or be employed as a platform to study cellular niches in health and disease. Either on their own or integrated with other materials, CD-ECMs can also be utilized as biomaterials to engineer tissues de novo or facilitate endogenous healing and regeneration. This review provides a brief overview over the methodologies used to facilitate CD-ECM deposition and manufacturing. It explores the versatile uses of CD-ECM in fundamental research and therapeutic approaches, while highlighting innovative strategies. Furthermore, current challenges are identified and it is accentuated that advancements in methodologies, as well as innovative interdisciplinary approaches are needed to take CD-ECM-based research to the next level.