Skin Scaffolds Research Articles

Quality of protein fibers assembly impacts biofunctional characteristics of a tissue engineering scaffold

Freeze-drying method is extensively used to produce porous materials in tissue engineering because of its versatility and use of non-toxic solvents. However, it has some significant drawbacks in terms of microstructure non-uniformity. To achieve a tissue-engineered skin scaffold with a desirable microstructure, we modified the freeze-drying technique by regulating heat transfer and control of the cooling rate during the freezing step. It could create a homogeneous porous structure with more equiaxed non-oriented pores. The efficiency of tissue engineering scaffold rests upon a few essential features such as suitable microstructure, controlled biodegradability, and adequate mechanical strength. In this work, we investigated the mechanical and degradation properties along with cell attachment and proliferation of the modified gelatin/chitosan scaffolds. Improved mechanical characteristics were found when a modified freeze-drying technique was applied for scaffold fabrication. Moreover, uniform microstructure with polygonal pores provided more resistance against the degradation by enzyme molecules. Enhanced interconnectivity between the pores of scaffolds, due to the usage of the aluminum mold, resulted a more flexible structure with higher biodegradation rate. MTT assay on the gelatin/chitosan scaffolds also confirmed higher cell proliferation for the aluminum over the PS mold. • Modified freeze-drying created a homogeneous porous structure with more equiaxed pores. • Improved mechanical characteristics were achieved by employing modified freeze-drying. • Uniform microstructure provided more resistance against the degradation. • An interconnected porous structure favored cell attachment and proliferation.

Conductive biomimetic bilayer fibrous scaffold for skin regeneration

The treatment of severely damaged wounds is a serious challenge as these wounds have poor self-healing capacity, take longer to heal, and are prone to becoming chronic wounds. To solve this problem, PCL/gelatin electrospinning nanofiber membranes were combined with rGO-loaded chitosan non-woven fabrics to prepare biomimetic bilayer skin scaffolds. Among them, the PCL/gelatin nanofiber membrane was used to simulate the epidermis layer with a dense structure, and the chitosan non-woven fabric was used to simulate the dermis layer with a loose structure. When the concentration of the spinning solution was 7 %, and the average fiber diameter was 241 nm, HaCaTs had the best cell proliferation and adhesion, and the re-epithelialization process was fast. To enhance the induction effect of scaffolds on dermal cells, the electroactive substance rGO was used to give the scaffold electrical conductivity. Considering the biocompatibility, the concentration of GO dispersion was controlled at 1 mg/mL, and the obtained CHI@ 1rGO scaffolds had high conductivity, as well as the improved mitochondrial membrane potential of HFF-1 s which increased cell viability. So the induction of HFF-1 s migration was obvious. After cross-linking composite scaffolds with glutaraldehyde, the scaffolds still showed good cytocompatibility, at the same time, the peel strength was increased from 7.21 cN to 350 cN, and the structural stability of the nanofiber membrane layer in the liquid environment was also enhanced. Both the moisture absorption and moisture permeability of composite scaffolds were improved, which could maintain the moist environment of the wound to a certain extent. Altogether, results showed that electroactive biomimetic bilayer fibrous scaffolds have great application potential in promoting skin tissue regeneration.

An Evaluation of the Treatment of Full-Thickness Wounds Using Adipose Micro-Fragments within a Liquid Dermal Scaffold

In full-thickness wounds, inflammation, lack of matrix deposition, and paucity of progenitor cells delay healing. As commercially available solid (sheet) scaffolds are unable to conform to wounds of varying shapes and sizes, we previously generated a nutritious, injectable, liquid skin substitute that can conform to wound topography. In combination with adipose micro-fragments as a viable source of progenitor cells, a composite, in situ forming skin substitute was tested for the treatment of silicon ring splinted full-thickness wounds in rats. The in vitro survivability and migratory capacity of adipocytes derived from rat micro-fragmented fat cultured in our scaffold was examined with a Live/Dead assay, showing viability and migration after 7 and 14 days. In vivo, the efficacy of our scaffold alone (LDS) or with adipose micro-fragments (LDS+A) was compared to a standard dressing protocol (NT). LDS and LDS+A showed ameliorated wound healing, including complete epithelialization and less immune cell infiltration, compared to the NT control. Our findings demonstrate that a 3D liquid skin scaffold is a rich environment for adipocyte viability and migration, and that the addition of adipose micro-fragments to this scaffold can be used as a rich source of cells for treating full-thickness wounds.

Biological Graft as an Innovative Biomaterial for Complex Skin Wound Treatment in Dogs: A Preliminary Report.

Complex wounds in dogs are a recurrent problem in veterinary clinical application and can compromise skin healing; in this sense, tissue bioengineering focused on regenerative medicine can be a great ally. Decellularized and recellularized skin scaffolds are produced to be applied in different and complex canine dermal wounds in the present investigation. Dog skin fragments are immersed in a 0.5% sodium dodecyl sulfate (SDS) solution at room temperature and overnight at 4 °C for 12 days. Decellularized samples are evaluated by histological analysis, scanning electron microscopy (SEM) and gDNA quantification. Some fragments are also recellularized using mesenchymal stem cells (MSCs). Eight adult dogs are divided into three groups for the application of the decellularized (Group I, n = 3) and recellularized scaffolds (Group II, n = 3) on injured areas, and a control group (Group III, n = 2). Wounds are evaluated and measured during healing, and comparisons among the three groups are described. In 30- and 60-day post-grafting, the histopathological analysis of patients from Groups I and II shows similar patterns, tissue architecture preservation, epithelial hyperplasia, hyperkeratosis, edema, and mononuclear inflammatory infiltrate. Perfect integration between scaffolds and wounds, without rejection or contamination, are observed in both treated groups. According to these results, decellularized skin grafts may constitute a potential innovative and functional tool to be adopted as a promising dog cutaneous wound treatment. This is the first study that applies decellularized and recellularized biological skin grafts to improve the healing process in several complex wounds in dogs, demonstrating great potential for regenerative veterinary medicine progress.

Single unit functionally graded bioresorbable electrospun scaffold for scar-free full-thickness skin wound healing.

Full-thickness wounds are difficult to heal spontaneously. Scaffolds, meant for treating full-thickness wounds, should ensure proper tissue regeneration, both structurally and functionally. An ideal scaffold should mimic the physical, mechanical and biochemical properties of natural skin. However, available mono- or bi-layer skin scaffolds lack in the precise architecture and functionality, thus, failing to provide scar-free regeneration of full-thickness skin wounds. These unmet challenges of scar-free skin regeneration have been addressed in the present study for the first time. This research deals with the synthesis of a low-cost, structurally and functionally graded single unit biodegradable polymeric scaffold. The functional gradient in this scaffold was achieved by varying polymer concentration and electrospinning parameters. This gradient in the scaffold provided the required microenvironment for proper functional and structural reconstruction of all the layers of natural skin. The mechanical property of the scaffold matched that of the natural skin. Besides, the degradation kinetics of the scaffold was in coordination with the regeneration time for the full-thickness wound. The porosity and hydrophilicity gradients of the scaffold helped it mimic the in vivo hypodermal, dermal and epidermal microenvironments of the skin, simultaneously. Co-culturing PCS-201 (dermal fibroblasts) and HaCaT (keratinocytes) on the scaffold resulted in successful regeneration through cellular proliferation, differentiation and organization of the skin tissue. The scaffold also displayed better wound healing in vivo, in terms of speedy wound closure and proper tissue regeneration, in comparison to the standard treatment. Altogether, this study successfully established a simple, one-step synthesis process of a functionally graded, bioresorbable scaffold for scar-free, native-like, structural and functional regeneration of full-thickness skin wounds. Due to cost-effectiveness, easy synthesis process and microarchitectural features, the designed scaffold possesses a potential of translation to a good commercial wound healing product.

Off-the-shelf acellular fetal skin scaffold as a novel alternative to buccal mucosa graft: the development and characterization of human tissue-engineered fetal matrix in rabbit model of hypospadiasis.

In this study, we aimed to develop a novel alternative to buccal mucosal graft from the acellular human fetal skin to manage hypospadias in a rabbit model. We optimized the decellularization protocol to develop and characterize the human tissue-engineered fetal dermal matrix as an "off-the-shelf" natural biomaterial. Human fetal skin was obtained at 16-19weeks gestational age with respect to a signed informed consent from parents under the university ethical committee approval. The dissected full-thickness fetal skin tissues were placed into SDS and Triton X-100 in different dosages to achieve the optimum decellularization protocol. Histopathology of the acellular fetal matrix was assessed by Hematoxylin & Eosin (H&E) and DAPI staining to confirm the removal of all cell materials, Masson's trichrome staining for collagen evaluation, DNA quantification for confirmation of DNA content, and scanning electron microscopy (SEM) for evaluation of scaffold microstructure. Immunohistochemistry (IHC) staining was used to detect specific dermal markers, namely vimentin, type I collagen, cytokeratin (CK)19. The prepared dermal scaffolds were then grafted on the 8 rabbit models of hypospadias. The rabbits underwent evaluations at 1, 2, 3, and 6months postoperatively. H&E, Masson's trichrome, DAPI staining, and SEM confirmed the significant removal of cells; meanwhile, the ECM was completely preserved. At the time of biopsy, after 2, 4, and 6months, no evidence of inflammation, fibrosis, necrosis, or rejection was observed. The grafted dermal scaffolds appeared histologically and anatomically normal. It was observed that the scaffolds were recellularized by circulating CD 34 + bone marrow stem cells (BMSCs) inside the body, implicating the body as a natural bioreactor. The application of acellular fetal skin (AFS) is a safe and feasible method that can decrease surgical time in a complex hypospadias reconstruction. Moreover, AFS demonstrated excellent angiogenesis characteristics and migration of the stem cells to the scaffold observed during the course of treatment. Novel natural AFS scaffold without cell seeding is an excellent alternative to buccal mucosal graft; hence, it can overcome the limitations concerning the graft size and prevent the creation of wounds in oral mucosal tissue.

The efficacy of a paeoniflorin-sodium alginate-gelatin skin scaffold for the treatment of diabetic wound: An in vivo study in a rat model

ObjectiveTo investigate the efficacy of a paeoniflorin-sodium alginate (SA)-gelatin skin scaffold for treating diabetic wound in a rat model. MethodsBioinks were prepared using various percentages of paeoniflorin in the total weight of a solution containing SA and gelatin. Skin scaffolds containing 0%, 1%, 3%, 5%, and 10% paeoniflorin were printed using 3D bioprinting technology, and scaffold microstructure was observed with scanning electron microscopy. Skin scaffolds were then used in rats with diabetic wounds. H&E staining, Masson staining, and immunohistochemical staining for IL-1β and CD31 were performed on days 7 and 14. ResultsAll skin scaffolds had a mesh-like structure with uniform pore distribution. Wounds healed well in each group, with the 1% and 3% groups demonstrating the most complete healing. H&E staining showed that skin accessory organs had appeared in each group. On day 7, collagen deposition in the 3% group was higher than in the other groups (P＜0.05), and IL-1β infiltration was lower in the 10% group than in the 3% group (P = 0.002). On day 14, IL-1β infiltration was not significantly different between the 10% and 3% groups (P = 0.078). The CD31 level was higher in the 3% group than in the other groups on days 7 and 14 (P＜0.05). ConclusionA 3% paeoniflorin-SA-gelatin skin scaffold promoted the healing of diabetic wounds in rats. This scaffold promoted collagen deposition and microvascular regeneration and demonstrated anti-inflammatory properties, suggesting that this scaffold type could be used to treat diabetic wounds.

Fabrication of polycaprolactone/collagen scaffolds reinforced by graphene oxide for tissue engineering applications

This study aims to fabricate skin scaffolds using polycaprolactone and collagen; the prepared scaffolds were reinforced using graphene oxide nanoparticles in both coating and mixed forms. The microstructure study confirmed the presence of carbon and oxygen elements in the structure of the scaffolds. It was also shown that the scaffold with the highest amount of graphene oxide in the mixture is the most hydrophilic one. Inversely, the tensile test showed that a higher amount of graphene oxide in the scaffold weakens its mechanical integrity. Lastly, the scaffolds with a coating of graphene oxide exhibited much lower cell viability in comparison to the scaffolds with graphene oxide in their structure; higher content of graphene oxide showed higher cell survival.

Investigation of co‐electrospun gelatin:TiO2/polycaprolactone:silk fibroin scaffolds for wound healing applications

AbstractElectrospinning is a facile technique to create porous nanofiber scaffolds with a high capability of natural environment mimicking. Here, co‐electrospinning of gelatin:TiO2, polycaprolactone:silk fibroin (G:T/P:F) was investigated with the aim of wound healing. Polycaprolactone improved the mechanical properties and gelatin:TiO2enhanced cellular interactions. Silk fibroin was extracted from theBombyx morisilkworm and increased the cellular and mechanical properties of the designed scaffolds. The morphology of the scaffolds was observed with field emission scanning electron microscopy (FESEM) and confirmed bead free porous nanofibrous structure. The fiber diameter rose after silk fibroin and TiO2addition but it was in the favorable fiber range. The contact angle, swelling, and mechanical properties of the G:T/P:F scaffolds supplied the requirements for skin tissue engineering. The designed scaffold showed over 80% cell viability with filopodia formation after 48 h according to cell adhesion observations and MTT assay results. The DAPI and LIVE/DEAD staining results confirmed high cell viability and the scratch assay observations proved the high wound healing potential of the G:T/P:F scaffolds. Furthermore, antibacterial properties were shown. It seems the designed scaffold can be useful in skin tissue regeneration. Further research may address the suggested skin scaffold.

Green Polymer Nanocomposites for Skin Tissue Engineering.

Fabrication of an appropriate skin scaffold needs to meet several standards related to the mechanical and biological properties. Fully natural/green scaffolds with acceptable biodegradability, biocompatibility, and physiological properties quite often suffer from poor mechanical properties. Therefore, for appropriate skin tissue engineering and to mimic the real functions, we need to use synthetic polymers and/or additives as complements to green polymers. Green nanocomposites (either nanoscale natural macromolecules or biopolymers containing nanoparticles) are a class of scaffolds with acceptable biomedical properties window (drug delivery and cardiac, nerve, bone, cartilage as well as skin tissue engineering), enabling one to achieve the required level of skin regeneration and wound healing. In this review, we have collected, summarized, screened, analyzed, and interpreted the properties of green nanocomposites used in skin tissue engineering and wound dressing. We particularly emphasize the mechanical and biological properties that skin cells need to meet when seeded on the scaffold. In this regard, the latest state of the art studies directed at fabrication of skin tissue and bionanocomposites as well as their mechanistic features are discussed, whereas some unspoken complexities and challenges for future developments are highlighted.

Fabrication of SA/Gel/C scaffold with 3D bioprinting to generate micro-nano porosity structure for skin wound healing: a detailed animal in vivo study

Bioprinting has exhibited remarkable promises for the fabrication of functional skin substitutes. However, there are some significant challenges for the treatment of full-thickness skin defects in clinical practice. It is necessary to determine bioinks with suitable mechanical properties and desirable biocompatibilities. Additionally, the key for printing skin is to design the skin structure optimally, enabling the function of the skin. In this study, the full-thickness skin scaffolds were prepared with a gradient pore structure constructing the dense layer, epidermis, and dermis by different ratios of bioinks. We hypothesized that the dense layer protects the wound surface and maintains a moist environment on the wound surface. By developing a suitable hydrogel bioink formulation (sodium alginate/gelatin/collagen), to simulate the physiological structure of the skin via 3D printing, the proportion of hydrogels was optimized corresponding to each layer. These results reveal that the scaffold has interconnected macroscopic channels, and sodium alginate/gelatin/collagen scaffolds accelerated wound healing, reduced skin wound contraction, and re-epithelialization in vivo. It is expected to provide a rapid and economical production method of skin scaffolds for future clinical applications.

MP22-13 OFF THE SHELF ACELLULAR FETAL SKIN SCAFFOLD AS A NOVEL ALTERNATIVE TO BUCCAL MUCOSA GRAFT: THE DEVELOPMENT AND CHARACTERIZATION OF HUMAN TISSUE ENGINEERED FETAL DERMAL MATRIX IN RABBIT MODEL OF HYPOSPADIASIS

You have accessJournal of UrologyCME1 May 2022MP22-13 OFF THE SHELF ACELLULAR FETAL SKIN SCAFFOLD AS A NOVEL ALTERNATIVE TO BUCCAL MUCOSA GRAFT: THE DEVELOPMENT AND CHARACTERIZATION OF HUMAN TISSUE ENGINEERED FETAL DERMAL MATRIX IN RABBIT MODEL OF HYPOSPADIASIS Abdol-Mohammad Kajbafzadeh, Soheila Sobhani, and Fahimeh Jafarnezhad-Ansariha Abdol-Mohammad KajbafzadehAbdol-Mohammad Kajbafzadeh More articles by this author , Soheila SobhaniSoheila Sobhani More articles by this author , and Fahimeh Jafarnezhad-AnsarihaFahimeh Jafarnezhad-Ansariha More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002561.13AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: To introduce a novel alternative to buccal mucosal graft from the acellular human fetal skin for management of hypospadias in rabbit model. To optimize the acellularization protocol for development and characterization of human tissue engineered fetal dermal matrix as an “off the shelf” natural biomaterial. METHODS: Human fetal skin were obtained (from the therapeutic abortion fetuses) with gestational age of 16-19 weeks with respect to a singed informed consent from parents following receiving the university ethical committee permission. The dissected full thickness fetal skin tissues were placed into SDS and Triton X-100 in different dosages to achieve the optimum decellularization protocol. Histopathology of the fetal acellular matrix were assess by hematoxcillin & eosin, DAPI staining for confirmation of removal of all cell materials, trichrome staining for collagen evaluation DNA quantification for confirmation of DNA content, scanning electron microscopy for evaluation of scaffold microstructure. Specific dermal markers (Vimentin, type I collagen, CK14) were depict by IHC. The prepared dermal scaffolds were then grafted into the induced model of hypospadias in 8 male rabbits. The rabbits were followed up for 1, 2, 3 and 6 months post operatively. RESULTS: In order to show the success of decellularization process, we characterized it with H&E, trichrome-Masson staining, DAPI and SEM which confirmed the significant removal of cells; meanwhile the ECM was completely preserved. At the time of biopsy after 2, 4 and 6 moths, no evidence of inflammation, fibrosis, necrosis or rejection was observed and the grafted dermal scaffolds appeared histologically and anatomically normal histologic appearance by recellularization of scaffold by circulating CD 34 + bone marrow stem cells “represent the body as a natural bioreactor”. CONCLUSIONS: The use of this novel “off the shelf” natural fetal skin scaffold without cell seeding is an excellent alterative to buccal mucosal graft and pave the road for decreasing surgical time (at least one hour) in complex hypospadias reconstruction. This method is safe, feasible with excellent angioneogenesis and cell seeding in due course without cell culture and cell seeding or shrinkage of the graft, no creation of oral mucosal wound and in addition, there will be no limitations of graft size for staged hypospadias cripple surgery. Source of Funding: There was no source of funding for this study © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e376 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Abdol-Mohammad Kajbafzadeh More articles by this author Soheila Sobhani More articles by this author Fahimeh Jafarnezhad-Ansariha More articles by this author Expand All Advertisement PDF DownloadLoading ...

808 Combination of Adipose Micro Fragments and Liquid Scaffold Improve Wound Healing Outcomes

IntroductionIn full-thickness wounds, high levels of inflammation, lack of matrix deposition and paucity of progenitor cells delays normal healing processes. One major problem with commercially available solid (sheet) scaffolds is their inability to conform to wounds of varying shapes and sizes. To overcome this, we previously generated a liquid, injectable skin substitute which can fill wounds of any shape and depth from bottom up and has all the necessary ingredients for skin cells to be nourished, proliferate, and migrate in. In combination with adipose micro fragments as a viable source of progenitor cells, a composite, in situ forming skin substitute was tested for treatment of silicon ring splinted wounds in rats.MethodsThe in vitro survival and migratory capacity of adipocytes derived from rat micro-fragmented fat when cultured in our 3D nutritional scaffold was examined with a Live/Dead assay. The efficacy of our combined liquid scaffold alone (MF) or with adipose micro fragments (MFA) in treating full thickness splinted wounds in rats was compared to a standard dressing protocol (NT). The healing process was monitored for 10 days. Following wound measurements, histological and immunofluorescent analyses were performed and compared.ResultsAdipose-derived cells migrated within the 3D nutritional liquid scaffold after 7 and 14 days. The number of red (dead) cells was negligent, indicating cell viability. In vivo, both MFA and MF showed both accelerated and ameliorated wound healing, including complete epithelialization and less immune cell infiltration, compared to the NT control. No significant differences were observed between the MF and MFA groups for any outcome.ConclusionsOur findings show that a 3D nutritional liquid skin scaffold is a rich environment for adipocyte viability and migration and that addition of adipose micro fragments to this scaffold can be used as a rich source of cells.

Preparation and evaluation of polycaprolactone/chitosan/Jaft biocompatible nanofibers as a burn wound dressing

Tissue engineering is an emerging method for replacing damaged tissues. In this study, the potential application of electrospun polycaprolactone/chitosan/ the internal layer of oak fruit (Jaft) as skin scaffolds was investigated. A combination of Polycaprolactone (PCL), chitosan (CH), and the internal layer of oak fruit (Jaft) was used to incorporate mechanical properties of synthetic polymers, biological properties of natural polymers, and antibacterial activity of Jaft. Physical and morphological characteristics of prepared scaffolds were investigated using a scanning electron microscope (SEM), mechanical analysis, swelling ratio, and contact angle. Moreover, chemical and biological properties were evaluated by Fourier-transform infrared spectroscopy (FTIR), chromatography, flow cytometry, DAPI staining, MTT assay, and trypan blue exclusion assay. Obtained results demonstrated that the fabricated scaffolds have good mechanical properties. Moreover, the addition of chitosan and Jaft to the PCL scaffolds improved their water absorption capacity as well as surface hydrophilicity. MTT results showed the fabricated nanofibrous scaffolds have adequate cell viability, which is higher than the cell culture plate at each time point of culture. Furthermore, SEM images of cultured scaffolds, trypan blue exclusion assay, and DAPI staining confirmed that fibroblast cells could be well-attached and proliferate on the PCL/CH/Jaft scaffolds. Results have proven that this novel bioactive scaffold has promising mechanical properties, suitable biocompatibility in vitro, and in vivo. Consequently, it could be a promising candidate for skin tissue engineering applications.

Conductive Polymeric-Based Electroactive Scaffolds for Tissue Engineering Applications: Current Progress and Challenges from Biomaterials and Manufacturing Perspectives.

The practice of combining external stimulation therapy alongside stimuli-responsive bio-scaffolds has shown massive potential for tissue engineering applications. One promising example is the combination of electrical stimulation (ES) and electroactive scaffolds because ES could enhance cell adhesion and proliferation as well as modulating cellular specialization. Even though electroactive scaffolds have the potential to revolutionize the field of tissue engineering due to their ability to distribute ES directly to the target tissues, the development of effective electroactive scaffolds with specific properties remains a major issue in their practical uses. Conductive polymers (CPs) offer ease of modification that allows for tailoring the scaffold’s various properties, making them an attractive option for conductive component in electroactive scaffolds. This review provides an up-to-date narrative of the progress of CPs-based electroactive scaffolds and the challenge of their use in various tissue engineering applications from biomaterials perspectives. The general issues with CP-based scaffolds relevant to its application as electroactive scaffolds were discussed, followed by a more specific discussion in their applications for specific tissues, including bone, nerve, skin, skeletal muscle and cardiac muscle scaffolds. Furthermore, this review also highlighted the importance of the manufacturing process relative to the scaffold’s performance, with particular emphasis on additive manufacturing, and various strategies to overcome the CPs’ limitations in the development of electroactive scaffolds.

Effects of two common acellular methods on the physicochemical properties of dermal acellular matrix

At present, acellular matrix is an effective replacement material for the treatment of skin damage, but there are few systematic evaluation studies on its performance. The experimental group of this study used two decellularization methods to prepare the matrix: one was the acellular matrix which sterilized with peracetic acid first (0.2% PAA/4% ethanol solution) and then treated with hypertonic saline (group A), the other was 0.05% trypsin/EDTA decellularization after γ irradiation (group B); and the control group was soaked in PBS (Group C). Then physical properties and chemical composition of the three groups were detected. Hematoxylin eosin (HE) staining showed that the acellular effect of group B was good. The porosity of group A and B were both above 84.9%. In group A, the compressive modulus of elasticity was (9.94 ± 3.81) MPa, and the compressive modulus of elasticity was (12.59 ± 5.50) MPa in group B. There was no significant difference between group A or B and group C. The total content of collagen in acellular matrix of group A and B was significantly lower than that of group C (1. 662 ± 0.229) mg/g, but there was no significant difference in the ratio of collagen Ⅰ/Ⅲ between group B and group C. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that there was no significant difference in microstructure. Qualitative detection of fibronectin and elastin in each group was basically consistent with that in group C. Therefore, acellular matrix of group B had better performance as scaffold material. The experimental results show that the acellular matrix prepared by γ-ray sterilization and decellularization of 0.05% Trypsin enzyme/EDTA could be used for the construction of tissue-engineered skin. It could also provide reference for the preparation and mounting of heterogeneous dermal acellular matrix. It was also could be used for electrostatic spinning or three-dimensional printed tissue engineered skin scaffold which could provide physical and chemical parameters for it.

Combining Biocompatible and Biodegradable Scaffolds and Cold Atmospheric Plasma for Chronic Wound Regeneration.

Skin regeneration is a quite complex process. Epidermal differentiation alone takes about 30 days and is highly regulated. Wounds, especially chronic wounds, affect 2% to 3% of the elderly population and comprise a heterogeneous group of diseases. The prevailing reasons to develop skin wounds include venous and/or arterial circulatory disorders, diabetes, or constant pressure to the skin (decubitus). The hallmarks of modern wound treatment include debridement of dead tissue, disinfection, wound dressings that keep the wound moist but still allow air exchange, and compression bandages. Despite all these efforts there is still a huge treatment resistance and wounds will not heal. This calls for new and more efficient treatment options in combination with novel biocompatible skin scaffolds. Cold atmospheric pressure plasma (CAP) is such an innovative addition to the treatment armamentarium. In one CAP application, antimicrobial effects, wound acidification, enhanced microcirculations and cell stimulation can be achieved. It is evident that CAP treatment, in combination with novel bioengineered, biocompatible and biodegradable electrospun scaffolds, has the potential of fostering wound healing by promoting remodeling and epithelialization along such temporarily applied skin replacement scaffolds.

Design and Fabrication of Sodium Alginate/Carboxymethyl Cellulose Sodium Blend Hydrogel for Artificial Skin.

Tissue-engineered skin grafts have long been considered to be the most effective treatment for large skin defects. Especially with the advent of 3D printing technology, the manufacture of artificial skin scaffold with complex shape and structure is becoming more convenient. However, the matrix material used as the bio-ink for 3D printing artificial skin is still a challenge. To address this issue, sodium alginate (SA)/carboxymethyl cellulose (CMC-Na) blend hydrogel was proposed to be the bio-ink for artificial skin fabrication, and SA/CMC-Na (SC) composite hydrogels at different compositions were investigated in terms of morphology, thermal properties, mechanical properties, and biological properties, so as to screen out the optimal composition ratio of SC for 3D printing artificial skin. Moreover, the designed SC composite hydrogel skin membranes were used for rabbit wound defeat repairing to evaluate the repair effect. Results show that SC4:1 blend hydrogel possesses the best mechanical properties, good moisturizing ability, proper degradation rate, and good biocompatibility, which is most suitable for 3D printing artificial skin. This research provides a process guidance for the design and fabrication of SA/CMC-Na composite artificial skin.

Non-uniform Kirigami Enhances Films Conformability

Developing films with great conformability has become a research hotspot in many fields. The conventional method to enhance conformability is to make the film thinner and more compliant, which usually compromises the strength of the structure. For example, developing functional medical bandages that can perfectly conform to the skin surface during cyclic bending of the joints is still a considerable challenge. In this paper, we propose a novel non-uniform kirigami to make the film achieve the same non-uniform auxetic (negative Poisson’s ratio) deformation as the skin around the joint area. By mapping the corresponding unit cells to the target surface, the surface can easily achieve the same deformation as the target skin without any alterations in its thickness or adhesion. As the obtained non-uniform kirigami film structure has the same deformation behavior as the target skin surface, the conformability of the structure can be guaranteed during the entire rotation process of the joints. Moreover, the proposed film is also expected to be used in novel biomaterials, such as smart bandages, skin scaffold, etc.

Chitosan/PVA Based Membranes Processed by Gamma Radiation as Scaffolding Materials for Skin Regeneration.

Some of the current strategies for the development of scaffolding materials capable of inducing tissue regeneration have been based on the use of polymeric biomaterials. Chitosan, in particular, due to its recognized biological activity has been used in a number of biomedical applications. Aiming the development of chitosan-based membranes with improved cell adhesion and growth properties to be used as skin scaffolds allowing functional tissue replacement, different formulations with chitosan of different molecular weight, poly (vinyl alcohol) and gelatin, were evaluated. To meet the goal of getting ready-to-use scaffolds assuring membranes’ required properties and sterilization, preparation methodology included a lyophilization procedure followed by a final gamma irradiation step. Two radiation dose values were tested. Samples were characterized by TGA, FTIR, and SEM techniques. Their hydrophilic properties, in vitro stability, and biocompatibility were also evaluated. Results show that all membranes present a sponge-type inner structure. Chitosan of low molecular weight and the introduction of gelatin are more favorable to cellular growth leading to an improvement on cells’ morphology and cytoskeletal organization, giving a good perspective to the use of these membranes as potential skin scaffolds.