Skin Scaffolds Research Articles

Skin-inspired gelatin-based flexible bio-electronic hydrogel for wound healing promotion and motion sensing

Next generation tissue-engineered skin scaffolds promise to provide sensory restoration through electrical stimulation in addition to effectively rebuilding and repairing skin. The integration of real-time monitoring of the injury motion activities can fundamentally improve the therapeutic efficacy by providing detailed data to guide the clinical practice. Herein, a mechanically-flexible, electroactive, and self-healable hydrogels (MESGel) was engineered for the combinational function of electrically-stimulated accelerated wound healing and motion sensing. MESGel shows outstanding biocompatibility and multifunctional therapeutic properties including flexibility, self-healing characteristics, biodegradability, and bioelectroactivity. Moreover, MESGel shows its potential of being a novel flexible electronic skin sensor to record the injury motion activities. Comprehensive in vitro and in vivo experiments prove that MESGel can facilitate effective electrical stimulation, actively promoting proliferation in Chinese hamster lung epithelial cells and therefore can accelerate favorable epithelial biology during skin wound healing, demonstrating an effective therapeutic strategy for a full-thickness skin defect model and leading to new-type flexible bioelectronics.

Fabrication and characterization of in vitro 2D skin model – An attempt to establish scaffold for tissue engineering

In the recent decade, tissue engineering has achieved noteworthy progress in artificial skin preparation. The present study is intended to harvest 2D skin from Bombyx mori cocoons and collagen type I with chicken endothelial cell culture for alleviating skin diseases like cancer. The Artificial 2D Skin is fabricated by seeding the endothelial cell, fibroblast and keratinocytes embedded in the silk sponge for 21 days, which results in a 2D skin. The fabricated 2D skin scaffold is subjected to material characterization and evaluated by UV absorption, FTIR, FESEM, swelling index, enzymatic degradation and antibacterial activity. The UV absorbance of sericin, fibroin and collagen are found at 215–240, 260−290 and 300 nm respectively. The results of FT-IR spectrum confirms the presence of proteinaceous substances. Moreover,FESEM shows a high degree of viable epidermis formation. The swelling index and enzymatic degradation is found as 30 %, 26.5 % respectively. The cell viabilitytest performed on different pus-forming bacteria which exhibited antibacterial property significantly at p<0.001. E. coliand has deprived viable conditions whencomparing with other organisms. From the above results, it is inferred that the 2D skin is equivalent to human skin which could be utilized for various skin therapy and tissue engineering.

Polysaccharide-based skin scaffolds with enhanced mechanical compatibility with native human skin

We report a custom-made technique to synthesize process-convenient skin scaffolds by tuning the mechanical properties of hydrogels based on a few naturally occurring polysaccharides to match the rheological properties of previously established benchmarks, i.e., the ex vivo native human skins. We studied the mechanical parameters using oscillatory shear rheology. At small strain amplitudes, the intrinsic elastic modulus showed an almost linear dependence in the middle and a changing rate profile at the two ends with concentration of the principal hydrogel component variant, i.e., kappa (κ)-carrageenan. At large strain amplitudes, the hydrogels demonstrated intercycle strain-softening behavior, the onset of which was directly proportional to the κ-carrageenan concentration. We observed a concentration match for the intrinsic elastic modulus of the benchmark within this sigmoidal curve fit. Contextually, we need to explore other potent polymeric hydrogel systems to achieve mechanical affinity in terms of multiple rheological parameters derived from both strain amplitude and angular frequency sweeps. Additionally, we carried out diffusion experiments to study caffeine permeation attributes. The hydrogels show improved barrier features with increasing κ-carrageenan concentration. In terms of the penetration flux and total cumulative amount of permeated caffeine, this enhanced mechanical adherence demonstrates comparable penetration features with the commercial 3D skin model.

Gliadin-mediated green preparation of hybrid zinc oxide nanospheres with antibacterial activity and low toxicity

The development of inorganic antibacterial agents that impart antibacterial properties to biomaterials has attracted wide attention. The paper introduced a kind of hybrid nanosphere antibacterial agent composed of wheat gliadin (WG) and zinc oxide (ZnO), with antibacterial efficacy and low toxicity. The ZnO/WG hybrid nanospheres were environment-friendly integrated by molecular self-assembly co-precipitating and freeze-drying transformation, and were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), atomic absorption spectroscopy (AAS), specific surface and pore size analysis, bacteriostasis test, reactive oxygen species (ROS) determination and safety evaluation. It was found that the prepared hybrid nanospheres were composed of two components, WG and ZnO, with a diameter scope of 100–200 nm; the content of ZnO in the hybrid nanospheres can reach 46.9–70.2% (w/w); the bacteriostasis tests proved that the prepared ZnO/WG nanospheres generating ROS, have a significant inhibitory effect on E. coli and S. aureus; furthermore, the ZnO/WG nanospheres are relatively safe and highly biocompatible in cells and mice. Therefore, the prepared novel ZnO/WG hybrid nanospheres were supposed to apply in the preparation of anti-infective wound dressings, tissue engineering skin scaffold materials, food, and cosmetics preservatives, and so on.

Electrospun polyurethane-gelatin artificial skin scaffold for wound healing

Native skin consists mainly of epidermal and dermal layers. Here in this work, we have constructed an artificial skin scaffold mimicking the bilayered structure of the native skin using electrospinning technique for wound healing. Polyurethane (PU) and Gelatin (Ge) were used for developing the epidermal layer and the dermal layer respectively. Ciprofloxacin HCl (Cip. HCl) a fluoroquinolone antibiotic was incorporated in both the layers for rapid wound healing. Morphology of the skin scaffold was studied using scanning electron microscopy (SEM) analysis and the chemical characterization was performed using FTIR spectroscopy. Water vapor transmission rate test and oxygen transmission rate test was conducted to evaluate the barrier properties of the scaffold. Thermal stability of the skin scaffold was evaluated using DSC and TGA while an understanding of the exudate absorbing capacity and degradation behavior of the scaffold was obtained from water absorption studies and in vitro degradation studies respectively. In vitro drug release study and drug release kinetics was explored to understand the release mechanism of Cip. HCl from the scaffold. Both the layers showed nano and micropores when analyzed using SEM. The dermal layer showed comparatively more water absorption capacity and degradation, hence providing a moist environment for the wound. The skin scaffold was permeable to water vapor and oxygen, and hence will speed up the process of wound healing. In vitro release for Cip. HCl showed a non-Fickian swelling type release with zero-order kinetics. Disk diffusion test conducted on the bilayers proved the antibacterial activity of the membrane. Hence the electrospun PU-Ge skin scaffold containing Cip. HCl is a promising candidate among modern day wound healing materials.

Comparative Morphological Characteristics of the Results of Implantation of Decellularized and Recellularized Porcine Skin Scaffolds.

The tissue reaction of pig skin to implantation of decellularized and recellularized dermal matrices on a formed wound defect was evaluated by histological methods on days 2, 5, 8, 16, and 20 after surgery. Differences in tissue response to different matrices were identified. In experimental wounds coated with decellularized dermal matrices, we observed the formation of a scar tissue, which required autodermoplasty on day 12 of the experiment. In wounds coated with recellularized dermal matrices, all layers of the skin completely recovered by day 20 after surgery with the formation of full dermal and epidermal layers. Our findings suggest that reparative morphological changes in the wound depend on the presence of fibroblasts in the implanted dermal matrix.

Microfluidic spinning-induced heterotypic bead-on-string fibers for dual-cargo release and wound healing.

The preparation of dual-release pharmaceutical microfibers provides an ideal material for new biomedical applications. We describe a microfluidic spinning method for engineering heterotypic bead-on-string fibers with the ability to carry dual cargos and to deliver on demand. The core of our technology is to combine microfluidic spinning with biomaterial preparation, in which hydrophobic and hydrophilic cargos can be integrated into a bead-on-string microfiber structure. We demonstrate the loading of bovine serum albumin (BSA) in the sodium alginate phase and ibuprofen in the polylactic acid (PLA) phase, respectively. The heterotypic bead-on-string fibers are biocompatible and show hemostatic ability in vivo. These heterotypic bead-on-string fibers are then woven as a skin scaffold and shown to promote wound healing by loading antibacterial and anti-inflammatory cargos.

Antibacterial Porous Electrospun Fibers as Skin Scaffolds for Wound Healing Applications.

Electrospun fiber scaffolds have a huge potential for the successful treatment of infected wounds based on their unique properties. Although several studies report novel drug-loaded electrospun fiber-based biomaterials, many of these do not provide information on their interactions with eukaryotic and bacterial cells. The main aim of this study was to develop antibacterial drug-loaded porous biocompatible polycaprolactone (PCL) fiber scaffolds mimicking the native extracellular matrix for wound healing purposes. Mechanical property evaluation and different biorelevant tests were conducted in order to understand the structure–activity relationships and reveal how the surface porosity of fibers and the fiber diameter affect the scaffold interactions with the living bacterial and eukaryotic fibroblast cells. Cell migration and proliferation assays and antibiofilm assays enabled us to enlighten the biocompatibility and safety of fiber scaffolds and their suitability to be used as scaffolds for the treatment of infected wounds. Here, we report that porous PCL microfiber scaffolds obtained using electrospinning at high relative humidity served as the best surfaces for fibroblast attachment and growth compared to the nonporous microfiber or nonporous nanofiber PCL scaffolds. Porous chloramphenicol-loaded microfiber scaffolds were more elastic compared to nonporous scaffolds and had the highest antibiofilm activity. The results indicate that in addition to the fiber diameter and fiber scaffold porosity, the single-fiber surface porosity and its effect on drug release, mechanical properties, cell viability, and antibiofilm activity need to be understood when developing antibacterial biocompatible scaffolds for wound healing applications. We show that pores on single fibers within an electrospun scaffold, in addition to nano- and microscale diameter of the fibers, change the living cell–fiber interactions affecting the antibiofilm efficacy and biocompatibility of the scaffolds for the local treatment of wounds.

Bacteria activated-macrophage membrane-coated tough nanocomposite hydrogel with targeted photothermal antibacterial ability for infected wound healing

A bacteria activated-macrophage membrane-coated tough nanocomposite hydrogel is fabricated by in situ polymerization of hydrogen bonding monomer N-acryloyl glycinamide loaded with polydopamine-modified gold nanorods (Au@PDA NRs), followed by coating bacteria-activated macrophage membrane (MM). The resultant E/SMM-PNAGA-Au@PDA NRs hydrogels exhibit high mechanical properties, excellent targeted photothermal antibacterial and wound healing capacity. • A macrophage membrane-coated hydrogel with a photothermal effect is fabricated. • The hydrogel can specifically recognize and capture the target bacteria. • The hydrogel enables healing of infected wound and harmless peeling. Antibacterial hydrogels have attracted extensive attention for preventing bacterial infection as wound dressing. However, development of broad-spectrum antibacterial hydrogel with a specific recognition ability and high strength remains challenging. In this work, a novel multifunctional nanocomposite antibacterial hydrogel with high strength and toughness is prepared by one-pot polymerization of hydrogen bonding monomer N-acryloyl glycinamide (NAGA) mixing with polydopamine-coated gold nanorods (Au@PDA NRs). The PNAGA-Au@PDA hydrogels are then coated with E. coli or S. aureus -pretreated macrophage membrane (termed as E/SMM-PNAGA-Au@PDA). Intriguingly, the resultant hydrogels can recognize specifically the source bacteria, and kill 98% bacteria in vitro under NIR irradiation for 5 min. Importantly, the SMM-PNAGA-Au@PDA hydrogel implanted on the dorsal area of rats can facilitate the infected wound healing and avoid secondary damage during peeling. This tough nanocomposite hydrogel coated with specific bacteria-activated macrophage membrane is promising to be developed as wound dressing, artificial skin and load-bearing scaffolds.

Biomimetic algal polysaccharide coated 3D nanofibrous scaffolds promote skin extracellular matrix formation

Development of functional biological substitutes for skin tissue engineering applications has observed several advancements over the past few decades. In this regard, intelligent extracellular matrix (ECM) mimetic scaffolds have recently evolved as a promising paradigm by presenting instructive cues directing cell-matrix communication, tissue remodeling and homeostasis. However, orchestring multitude attributes of skin ECM yet presents an intriguing challenge to be addressed. In the present work, we have developed an in vitro skin scaffold by coating a bio-mimetic ECM cue κ-carrageenan on electrospun nanofibers for the first time. κ-Carrageenan, a natural sulfated algal polysaccharide exhibits close similarity with native glucosaminoglycans (GAGs) of skin ECM. On the other hand, electrospun nanofibers resemble the 3D nano-topographic architecture of ECM. In the coated form, κ-carrageenan could provide the biochemical cues necessary for cellular functions on the nanofibrous scaffold, thereby mimicking the native 3D microenvironment of skin ECM. The nano-architecture of the electrospun matrix is retained in the fabricated scaffold even after coating with κ-carrageenan. The developed biomimetic scaffold significantly supplements adhesion, growth, infiltration, survival and proliferation of fibroblasts. Furthermore, enhanced gene expression and excessive secretion of collagen proteins by fibroblasts communicate a conducive skin ECM micro-environment formation on the algal polysaccharide coated nanofibrous scaffold. Taken together, these findings present a simple yet effective strategy for the fabrication of ECM mimetic scaffold for promising skin tissue engineering applications.

Matrisome Provides a Supportive Microenvironment for Skin Functions of Diverse Species.

A biomaterial scaffold is a promising tool employed to drive tissue regeneration. This technology has been successfully applied in human tissue rebuilding, particularly for the skin. Meanwhile, there is still room for further improvement, such as maintaining sufficient functionality of a biomaterial scaffold. Here, we developed a new decellularization method to generate a complete anatomical skin biomatrix scaffold with a preserved extracellular matrix (ECM) architecture. We performed proteomic and bioinformatic analyses of the skin scaffold maps of humans, pigs, and rats and systematically analyzed the interaction between ECM proteins and different cell types in the skin microenvironment. These interactions served to quantify the structure and function of the skin's Matrisome comprising core ECM components and ECM-associated soluble signaling molecules required for the regulation of epidermal development. We primarily found that the properties of the skin ECM were species-specific. For example, the composition and function of the ECM of the human skin were more similar to those of pigs compared with those of rats. However, the skin ECM of the pig was significantly deficient in its enzyme systems and immune regulatory factors compared with that of humans. These findings provide a new understanding of the role of the skin ECM niche as well as an attractive strategy that can apply tissue engineering principles to skin biomatrix scaffold materials, which promises to accelerate and enhance tissue regeneration.

Preparation and Characterization of PHBV/PEO/AZ‐Gelatin Electrospun Mats with Photochemical Surface Modification: The Role of AZ‐Gelatin

AbstractAs ideal tissue engineering scaffold, surface feature plays an important role in cell adhesion and proliferation. In order to improve cytocompatibility of poly(3‐hydroxybutyrate‐co‐hydroxyvalerate) (PHBV) and polyethylene oxide (PEO) synthetic materials, in this study, photochemical surface modification is applied in electrospinning field for the first time. Azidobenzoic acid‐modified gelatin (AZ‐gelatin) as bioactive protein is successfully fixed on PHBV/PEO electrospun mats by photochemical technique without any crosslinking agent. In vitro degradation and cell culture results show that PHBV/PEO/AZ‐gelatin electrospun mats have excellent cell adhesion and proliferation compared with PHBV and PHBV/PEO electrospun mats. But, by contrast with PHBV/PEO electrospun mats, the fiber diameter of PHBV/PEO/AZ‐gelatin mats increased, and the porosity and mechanical properties decrease. Nonetheless, PHBV/PEO/AZ‐gelatin‐0.01 mg mL−1 electrospun mats have shown better morphology (fiber diameter 600 nm, porosity 88%), mechanical properties (4.2 MPa), and water vapor transmission rate (2301 g m−2 day−1), which has great potential as artificial skin scaffold in tissue regeneration field.

Biomedical Applications of Hemicellulose-Based Hydrogels.

Hydrogel has a three-dimensional network structure that is able to absorb a large amount of water/liquid and maintain its original structure. Hemicellulose (HC) is the second most abundant polysaccharide after cellulose in plants and a heterogeneous polysaccharide consisting of various saccharide units. The unique physical and chemical properties of hemicellulose make it a promising material for hydrogels. This review first summarizes the three research hotspots on the hemicellulose-based hydrogels: intelligence, biodegradability and biocompatibility. It also overviews the progress in the fabrication and applications of hemicellulose hydrogels in the drug delivery system and tissue engineering (articular cartilage, cell immobilization, and wound dressing). Hemicellulose-based hydrogels have many unique properties, such as stimuliresponsibility, biodegradability and biocompatibility. Interpenetrating networking can endow appropriate mechanical properties to hydrogels. These properties make the hemicellulose-based hydrogels promising materials in biomedical applications such as drug delivery systems and tissue engineering (articular cartilage, cell immobilization, and wound dressing). Hydrogels have been widely used in biomedicine and tissue engineering areas, such as tissue fillers, drug release agents, enzyme encapsulation, protein electrophoresis, contact lenses, artificial plasma, artificial skin, and tissue engineering scaffold materials. This article reviews the recent progress in the fabrication and applications of hemicellulose-based hydrogels in the biomedical field.

Compact and tunable stretch bioreactor advancing tissue engineering implementation. Application to engineered cardiac constructs

Physical stimuli are crucial for the structural and functional maturation of tissues both in vivo and in vitro. In tissue engineering applications, bioreactors have become fundamental and effective tools for providing biomimetic culture conditions that recapitulate the native physical stimuli. In addition, bioreactors play a key role in assuring strict control, automation, and standardization in the production process of cell-based products for future clinical application. In this study, a compact, easy-to-use, tunable stretch bioreactor is proposed. Based on customizable and low-cost technological solutions, the bioreactor was designed for providing tunable mechanical stretch for biomimetic dynamic culture of different engineered tissues. In-house validation tests demonstrated the accuracy and repeatability of the imposed mechanical stimulation. Proof of concepts biological tests performed on engineered cardiac constructs, based on decellularized human skin scaffolds seeded with human cardiac progenitor cells, confirmed the bioreactor Good Laboratory Practice compliance and ease of use, and the effectiveness of the delivered cyclic stretch stimulation on the cardiac construct maturation.

Bioactive antibacterial bilayer PCL/gelatin nanofibrous scaffold promotes full-thickness wound healing.

Treatment of diabetic, chronic, and full-thickness wounds is a challenge as these injuries usually lead to infections that cause delayed and inappropriate healing. Therefore, fabrication of skin scaffolds with prolonged antibacterial properties are of great interest. Due to this demand, bilayered nanofibrous scaffolds were fabricated based on polycaprolactone and gelatin. The top layer of these scaffolds contained amoxicillin as a model drug and the bottom layer was loaded with zinc oxide nanoparticles to accelerate wound healing. Several characterization techniques including FTIR, SEM, swelling, tensile test, in vitro degradation, drug release, antibacterial activity, and MTT assay were used to assess physical, mechanical, and biological properties of produced nanofibers. SEM results demonstrated that bilayered scaffolds have smooth bead-free microstructures while in vitro release test showed that samples have a sustained release for amoxicillin up to 144h (tested time). Disk diffusion assessment confirmed the potency of scaffolds for hindering bacterial growth while results of cytotoxicity evaluation revealed that scaffolds could effectively accelerate cell proliferation. Finally, in vivo tests on full-thickness rat models revealed that fabricated nanofibers accelerate wound contraction, increase collagen deposition and angiogenesis, and prevent scar formation. Altogether, results showed that fabricated scaffolds are promising candidates for treatment of full-thickness wounds.

Development of a polyvinyl alcohol/sodium alginate hydrogel-based scaffold incorporating bFGF-encapsulated microspheres for accelerated wound healing

In the present study, a hybrid microsphere/hydrogel system, consisting of polyvinyl alcohol (PVA)/sodium alginate (SA) hydrogel incorporating PCL microspheres is introduced as a skin scaffold to accelerate wound healing. The hydrogel substrate was developed using the freeze-thawing method, and the proportion of the involved polymers in its structure was optimized based on the in-vitro assessments. The bFGF-encapsulated PCL microspheres were also fabricated utilizing the double-emulsion solvent evaporation technique. The achieved freeze-dried hybrid system was then characterized by in-vitro and in-vivo experiments. The results obtained from the optimization of the hydrogel showed that increasing the concentration of SA resulted in a more porous structure, and higher swelling ability, elasticity and degradation rate, but decreased the maximum strength and elongation at break. The embedding of PCL microspheres into the optimized hydrogel structure provided sustained and burst-free release kinetics of bFGF. Besides, the addition of drug-loaded microspheres led to no significant change in the degradation mechanism of the hydrogel substrate; however, it reduced its mechanical strength. Furthermore, the MTT assay represented no cytotoxic effect for the hybrid system. The in-vivo studies on a burn-wound rat model, including the evaluation of the wound closure mechanism, and histological analyses indicated that the fabricated scaffold efficiently contributed to promoting cell-induced tissue regeneration and burn-wound healing.

Identification of a fibrin concentration that promotes skin cell outgrowth from skin explants onto a synthetic dermal substitute

SummaryBackgroundOur overall objective is to develop a single-stage in-theatre skin replacement by combining small explants of skin with a synthetic biodegradable dermal scaffold. The aim of the current study is to determine the concentration of fibrin constituents and their handling properties for both adhering skin explants to the scaffold and encouraging cellular outgrowth to achieve reepithelialization.MethodsSmall skin explants were combined with several concentrations of thrombin (2.5,4.5,and 6.5 I.U) and fibrinogen (18.75,67, and 86.5 mg/ml), cultured in Green's media for 14 days and cellular outgrowth was measured using Rose Bengal staining. They were also cultured on electrospun scaffolds for 14 and 21 days. Hematoxylin and eosin (H&E) staining was undertaken to visualize the interface between skin explants and scaffolds and metabolic activity and collagen production were assessed.ResultsA thrombin/fibrinogen combination of 2.5 I. U/ml /18.75 mg/ml showed significantly greater cell viability as assessed by Rose Bengal stained areas at days 7 and 14. This was also seen in DAPI images and H&E stains skin explant/scaffold constructs. Fibrin with a concentration of thrombin 2.5 I.U./ml took 5–6 min to set, which is convenient for distributing skin explants on the scaffold.ConclusionThe study identified concentrations of thrombin (2.5 I.U/ml) and fibrinogen (18.75 mg/ml), which were easy to handle and aided the retention of skin explants and permitted cell outgrowth from explants.

Both Tough and Soft Double Network Hydrogel Nanocomposite Based on O‐Carboxymethyl Chitosan/Poly(vinyl alcohol) and Graphene Oxide: A Promising Alternative for Tissue Engineering

A reinforced double network (DN) hydrogel as a candidate for skin scaffold was prepared. It consists of O‐carboxymethyl chitosan, polyvinyl alcohol, honey, CaCl2, and graphene oxide. The various concentrations of CaCl2, namely, 30, 45, and 60 wt% were investigated. Besides, the GO content was studied as 3, 5, and 10 wt%. The structure of the DN was characterized by Fourier‐transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, X‐ray diffraction, energy dispersive X‐ray and Brunauer‐Emmett‐Teller were evaluated. The mechanical properties were studied, too. It showed that the DN with 45 wt% CaCl2 was optimized. Also, swelling mechanism was investigated. Moreover, with the increase in GO content, the mechanical strength was increased. The cytotoxicity was evaluated and it was indicated that DN with 45% CaCl2 and 5% GO had an acceptable level of biocompatibility. Moreover, scanning electron microscopy images showed the porous structure of the DN nanocomposite. Thus, the DN has the potential to be applied in tissue engineering as a skin scaffold. POLYM. ENG. SCI., 60:889–899, 2020. © 2020 Society of Plastics Engineers

Double crosslinked HLC-CCS hydrogel tissue engineering scaffold for skin wound healing

Skin defects caused by various reasons are currently common clinical problems. At present, hydrogels have been proposed as tissue-engineered skin scaffolds to regenerate the tissues of the defect. We used human-like collagen (HLC), which was isolated and purified after high-density fermentation of recombinant E. coli BL21 The gel uses HLC and carboxymethylated chitosan (CCS) as raw materials and combines enzyme-chemical double cross-linking technology to form a three-dimensional porous network structure that mimics the human extracellular matrix, providing attachment points and nutrients for cell growth and proliferation. For comparison, we used a common hydrogel raw material, gelatin, to prepare a hydrogel in the same way. The experimental results show that the HLC-CCS skin scaffold hydrogel has good mechanical properties, high porosity and good histocompatibility. And full-thickness skin defect repair experiments show that this hydrogel has a good ability to promote skin tissue regeneration at the wound. In summary, this HLC-based double-crosslinked hydrogel can be used as a project strategy for skin defect repair.

Hair follicle stem cells combined with human allogeneic acellular amniotic membrane for repair of full thickness skin defects in nude mice.

Repair of large skin defects caused by burns, trauma, or tumor operations is a clinical challenge. Hair follicle stem cells (HFSCs) are involved in epithelialization of wounds, formation of new hair follicles and promote vascularization in the newly formed skin, and human acellular amniotic membrane (hAAM) is a promising scaffold for skin substitute. Here, we investigated the ability of rat HFSCs (rHFSCs) combined with an hAAM to repair full thickness skin defects in nude mice. The effect of the rHFSC-hAAM composite on the repair of skin defects in nude mice was assessed by hematoxylin and eosin staining, immunohistochemistry, and EdU-labeled cell tracking. Isolated and cultured rHFSCs had strong cloning and proliferation potentials. Immunofluorescence staining and flow cytometry assays showed that rHFSCs expressed high levels of integrin α6, CK15, p63, and Sox9. Cells cultured in hAAM showed flaky and cluster-like morphology and were able to adhere and grow effectively. After transplantation, the rHFSC-hAAM composite promoted wound healing in nude mice. Moreover, cells in the rHFSC-hAAM composite were directly involved in hair follicle formation and angiogenesis of tissue around the hair follicle. These results provide an experimental and theoretical basis for the clinical application of HFSCs in repair of human skin defects and a new approach for skin tissue engineering.