Aloe vera incorporated biomimetic nanofibrous scaffold: a regenerative approach for skin tissue engineering

Review of Malaysian medicinal plants with potential wound healing activity

Wound is defined as the damage to biological tissues including skin, mucous membranes and organ tissues. The acute wound heals in less than 4 weeks without complications, while a chronic wound takes longer than 6 weeks to heal. Wound healing occurs in 4 phases, namely, coagulation, inflammatory, proliferative and remodeling phases. Triclosan and benzalkonium chloride are commonly used as skin disinfectants in wound healing. However, they cause allergic contact dermatitis and antibiotic resistance. Medicinal plants are widely studied due to the limited availability of wound healing agents. The present review included six commonly available medicinal plants in Malaysia such as Aloe barbadensis Miller, Carica papaya Linn., Centella asiatica Linn., Cymbopogon nardus Linn., Ficus benghalensis Linn. and Hibiscus rosa sinensis Linn. Various search engines and databases were used to obtain the scientific findings, including Google Scholar, ScienceDirect, PubMed Central and Research Gate. The review discussed the possible mechanism of action of medicinal plants and their active constituents in the wound healing process. In addition, their application in nanotechnology and wound dressings was also discussed in detail.

Core-shell nanofibers containing L-arginine stimulates angiogenesis and full thickness dermal wound repair

Despite the advances in medicine, wound healing is still challenging and piques the interest of biomedical engineers to design effective wound dressings using natural and artificial polymers. In present study, coaxial electrospinning was employed to fabricate core-shell nanofiber-based wound dressing, with core composed of polyacrylamide (PAAm) and shell comprising 0.5 % solution of L-Arginine (L-Arg) in aloe vera and keratin (AloKr). Aloe vera and keratin were added as natural polymers to promote angiogenesis, reduce inflammation, and provide antibacterial activity, whereas PAAm in core was used to improve the tensile properties of the wound dressing. Moreover, L-Arg was incorporated in shell to promote angiogenesis and collagen synthesis. The fiber diameter of PAAm/(AloKr/L-Arg) core-shell fibers was (93.33 ± 35.11 nm) with finer and straighter fibers and higher water holding capacity due to increased surface area to volume ratio. In terms of tensile properties, the PAAm/(AloKr/L-Arg) core-shell nanofibers with tensile strength and elastic modulus of 2.84 ± 0.27 MPa and 62.15 ± 5.32 MPa, respectively, showed the best mechanical performance compared to other nanofibers tested. Furthermore, PAAm/(AloKr/L-Arg) exhibited the highest L-Arg release (87.62 ± 3.02 %) and viability of L929 cells in vitro compared to other groups. In addition, the highest rate of in vivo full thickness wound healing was observed in PAAm/(AloKr/L-Arg) group compared to other groups. It significantly enhanced the angiogenesis, neovascularization, and cell proliferation. The prepared PAAm/(AloKr/L-Arg) core-shell nanofibrous dressing could be promising for full-thickness wound healing.

Fabrication, Properties, and Stability of Oregano Essential Oil and Sodium Alginate-Based Wound-Healing Hydrogels

The wound dressings fabricated by polymers and oregano essential oil (OEO) can be very effective as a hydrogel. The current study has been focused on fabricating the hydrogel membranes of oregano oil encapsulated as an antibacterial agent into sodium alginate (SA) solution by solvent casting method and then evaluated the antibacterial, antioxidant activity, and physicochemical performance of SA/OEO-based polymeric membranes. The polymeric interactions, surface morphology, water absorption capability, thermal stability, and encapsulation efficiency were investigated by FT-IR, SEM, swelling ratio, DSC, and encapsulation efficiency. The percentage encapsulation efficiency of essential oil was 40.5%. FTIR validated the presence of molecular interaction between individual components. SEM images showed a rough and porous appearance for hydrogel membranes. Moreover, DSC showed that the fabricated membranes were thermally stable. The inclusion of more content OEO decreased swelling ratios. The antioxidant test was carried out by DPPH assay and antibacterial test through disc diffusion method against microbes. The results revealed that membranes containing the highest content of OEO had more excellent antioxidant and antibacterial efficacy. Therefore, the polymeric membranes of sodium alginate loaded with oregano essential oil can be employed as an effective wound-healing candidate.

Fabrication of ECM Mimicking Bioactive Scaffold: A Regenerative Approach for MSC Mediated Applications

Biomaterials are feasible resources that aids to replace damaged structures in our bodies. The most biologically active flora is Aloe vera which has many bioactive compounds that are anti-inflammatory, antimicrobial, and have ECM mimicking protein content which helps in the healing of wounds and also acts as an ECM factor for stem cell homing and differentiation. The Aloe vera containing 10 w/v of gelatin was lyophilized. Scaffolds had sharper morphology, greater hydrophilic properties, and a Young's modulus of 6.28 MPa and 15.9 MPa of higher tensile strength are desirable. In tissue engineering and regenerative medicine, biologically active scaffolds have been producing hopeful outcomes in both restoration and replacement, respectively. The objective of the present investigation is to test the idea that incorporating gelatin to Aloe vera scaffolds might enhance their structure, good biocompatibility, and possibly even bioactivity. The SEM picture of the composite scaffold revealed pore walls. The scaffolds had linked pores with diameters ranging from 93 to 296 μm. Aloe vera and the matrix interact well, according to the FTIR study, which could lead to a reduction in the amount of water-binding sites and a reduction in the material's ability to absorb water. Aloe vera with 10% gelatin (AV/G) scaffold was investigated for different biological reactions of human gingival tissue mesenchymal stem cells (MSCs) in terms of cell proliferation, morphology, and cell migration. The results demonstrated the potential of the AV/G scaffold as a biomaterial that offers new insight in the field of tissue engineering.

Asymmetric tri-layer sponge-nanofiber wound dressing containing insulin-like growth factor-1 and multi-walled carbon nanotubes for acceleration of full-thickness wound healing

To more closely resemble the structure of natural skin, multi-layered wound dressings have been developed. Herein, a tri-layer wound dressing was prepared containing a polyacrylamide (PAAm)-Aloe vera (Alo) sponge that had been incorporated with insulin-like growth factor-1 (IGF1) to provide a porous absorbent layer, which was able to promote angiogenesis. Alo nanofibers with multi-walled carbon nanotubes (MWCNT) were electrospun into the bottom layer to increase cell behavior, and a small film of stearic acid was put as a top layer to avoid germy penetration. In comparison to bilayer dressing, the tensile strength increased by 17.0 % (from 0.200 ± 0.010 MPa to 0.234 ± 0.022 MPa) and the elastic modulus by 45.6 % (from 0.217 ± 0.003 MPa to 0.316 ± 0.012 MPa) in the presence of Alo nanofibers containing 0.5 wt% of MWCNT at the bottom layer of Trilayer0.5 dressing. The release profile of IGF1, the antibacterial activity and the degradability of different wound dressings were investigated. Trilayer0.5 indicated the highest cell viability, cell adhesion and angiogenic potential among the prepared dressing materials. In-vivo rat model revealed that the Trilayer0.5 dressing treated group had the highest rate of wound closure and wound healing within 10 days compared to other groups.

Phytoconstituent-Loaded Nanofibrous Meshes as Wound Dressings: A Concise Review

In the past, wounds were treated with natural materials, but modern wound dressings include functional elements to expedite the process of healing and to improve skin recovery. Due to their exceptional properties, nanofibrous wound dressings are now the most cutting-edge and desirable option. Similar in structure to the skin’s own extracellular matrix (ECM), these dressings can promote tissue regeneration, wound fluid transportation, and air ductility for cellular proliferation and regeneration owing to their nanostructured fibrous meshes or scaffolds. Many academic search engines and databases, such as Google Scholar, PubMed, and Sciencedirect, were used to conduct a comprehensive evaluation of the literature for the purposes of this investigation. Using the term “nanofibrous meshes” as a keyword, this paper focuses on the importance of phytoconstituents. This review article summarizes the most recent developments and conclusions from studies on bioactive nanofibrous wound dressings infused with medicinal plants. Several wound-healing methods, wound-dressing materials, and wound-healing components derived from medicinal plants were also discussed.

Recent Progress of Electrospun Herbal Medicine Nanofibers

Herbal medicine has a long history of medical efficacy with low toxicity, side effects and good biocompatibility. However, the bioavailability of the extract of raw herbs and bioactive compounds is poor because of their low water solubility. In order to overcome the solubility issues, electrospinning technology can offer a delivery alternative to resolve them. The electrospun fibers have the advantages of high specific surface area, high porosity, excellent mechanical strength and flexible structures. At the same time, various natural and synthetic polymer-bound fibers can mimic extracellular matrix applications in different medical fields. In this paper, the development of electrospinning technology and polymers used for incorporating herbal medicine into electrospun nanofibers are reviewed. Finally, the recent progress of the applications of these herbal medicine nanofibers in biomedical (drug delivery, wound dressing, tissue engineering) and food fields along with their future prospects is discussed.

Aloe vera incorporated starch-64S bioactive glass-quail egg shell scaffold for promotion of bone regeneration

Simultaneous promotion of osteoconductive and osteoinductive characteristics through combining bioactive glasses with natural polymers is still a challenge in bone tissue engineering. Starch, 64S bioactive glass (BG), aloe vera (AV) and quail eggshell powder (QE) were utilized to achieve biodegradable, bioactive, biocompatible and mechanically potent multifunctional scaffolds, using freeze-drying mechanism. Cell viability for starch-BG-AV-QE scaffolds at 3 and 7 day intervals was reported to be over 95 %. Acridine orange staining was employed to study live/dead cells cultured on the scaffolds. The high sufficiency of starch-BG-AV-QE scaffolds in osteogenic differentiation and extracellular matrix mineralization was confirmed through alkaline phosphatase activity and alizarin red staining assessments after 7 and 14 days of cell culture. High compressive strength, managed biodegradability and expression of osteocalcin and osteopontin as late markers of osteogenic differentiation were also reached in the range of 30-75 % for starch-BG-AV-QE scaffolds. Hence, starch-BG-AV-QE scaffolds with ideal physico-mechanical and biological characteristics can be considered as promising candidates for promotion of bone regeneration.

Understanding the cellular response of human tenon fibroblast on polycaprolactone-Aloe vera blend fiber

The signalling response is determined by the cell's reaction to different biochemical and biophysical inputs such as stiffness, topological, and structural alignment. The surface patterns at the nano-scale can be an influential factor in cell signalling behaviour. It is important to understand the cellular response to the biophysical cues for biomedical applications. Biomaterials have an important role in regenerative tissue engineering. In this study, we have fabricated electrospun polycaprolactone (PCL) and PCL-Aloe vera (PCL-AV) nanofibrous matrix and studied its effect on the human tenon fibroblast (HTF) cellular and morphological changes. The electrospun fibers were characterized using Scanning Electron Microscope (SEM), Fourier Transform Infrared spectroscopy (FTIR), Atomic Force Microscopy (AFM) and Brunaur, Emette and Teller (BET) analysis for their morphology, composition, topography, surface area and porosity. The results revealed fiber size, roughness and porosity has been altered by addition of AV. The HTF cell viability, proliferation and expression of focal adhesion proteins, such as FAK, Ezrin, Vasp and Cofilin on the PCL-AV fiber matrix were examined. The results showed a change in cellular morphology and a significant change in the cofilin phosphorylation on PCL-AV nanofiber. The influence of Aloe vera composition on the nano-dimension of the PCL has made a significant impact on the cellular morphology at both gene and protein levels. This observation suggests that AV composition in the nanofiber can significantly influence the HTF cellular adhesions.

Development of Eco-Friendly Nanomembranes of Aloe vera/PVA/ZnO for Potential Applications in Medical Devices

Due to the current COVID-19 pandemic, there is a crucial need for the development of antimicrobial and antiviral personal protective equipment such as facemasks and gowns. Therefore, in this research we fabricated electrospun nanofibers composite with polyvinyl alcohol, aloe vera, and zinc oxide nanoparticles for end application in medical devices. Electrospun nanofibers were made with varying concentrations of aloe vera (1%, 2%, 3%, 4%) having a constant concentration of ZnO (0.5%) with varying concentrations of ZnO nanoparticles (1%, 2%, 3%, 4%) having a constant concentration of aloe vera (0.5%). To check the morphology and composition, all prepared nanofibers were subjected to different characterization techniques, such as Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR). In addition, its antimicrobial activity was checked both with qualitative and quantitative approaches against gram-positive (Staphylococcus aureus) bacteria and gram-negative (Escherichia coli) bacteria. The results suggest that increasing ZnO concentration kills and inhibits bacterial growth more proficiently compared to increasing aloe vera concentration in electrospun nanofibers; the highest antimicrobial was found with 4% ZnO, killing almost 100% of gram-positive (Staphylococcus aureus) bacteria and 99.2% of gram-negative (Escherichia coli) bacteria. These fabricated nanofibers have potential applications in medical devices and would help control the spread of many diseases.

Mesoporous silica incorporated PCL/Curcumin nanofiber for wound healing application

Electrospinning, a recent fast-emerging technique highly applicable in the production of nanofibers has gained vast recognition owing to its explicit applications in various domains. Amongst which, the production of nanoscaffolds for wound healing applications has been focused recently due to advantages over conventional wound healing methods. In the present research, a composite nanoscaffold comprising SBA-15 (Santa Barbara Amorphous), amine functionalized SBA-15 polycaprolactone (PCL) and curcumin was investigated for its potentiality in wound healing therapeutics. The high biocompatibility and cell adhesion of amine functionalized SBA-15 and the widely explored antimicrobial properties of curcumin added benefit for the wound healing target. The prepared highly interconnected electrospun fibers with porous structure were characterized through various studies such as FTIR, XRD, SEM and EDAX. Further, antibacterial studies against both Gram positive (Bacillus subtilis) and Gram negative (Escherichia coli) strains revealed an improved zone of inhibition. Major invitro studies such as cell migration, proliferation, bio-compatibility was experimented through cell adhesion and live and dead assay using Swiss 3T6 cell lines. In vivo studies on female Wister rats using the fabricated nanofibers incorporated with curcumin and amine functionalized SBA-15 showed 99% scar-less wound healing within 21 days. Re-epithelization of tissue, collagen deposition and formation of granulation tissue were observed from the results of Hematoxylin-Eosin and Masson's tri-chrome staining. From the observations, it can be concluded that the fabricated nanoscaffold could be an effective substrate for wound healing therapeutics.

Rationally design of electrospun polysaccharides polymeric nanofiber webs by various tools for biomedical applications: A review

Nanofibers have a particular benefit when delivering a spectrum of therapeutic drugs for diverse biomedical applications. Nanofibers are easily fabricated from cellulose acetate, chitosan, polycaprolactone, and other polymers with regulated morphology and release profiles due to nanotechnology's recent advancement. This review will provide the latest approaches to the fabrication of electrospun nanofibers containing herbal extracts, antimicrobial peptides, and antibiotics for wound-healing potential. Besides, synthesis and evaluation of nanofibrous mats, including conducting polymer and evaluate their possibility for wound healing. In addition, nanofibers are loaded with some drugs for skin cancer treatment and contain growth factors for tissue regeneration. Also, the current two-dimensional nanofibers limitations and the various techniques for convert two-dimensional to three-dimension nanofibers to avoid these drawbacks. Moreover, the future direction in improving the three-dimensional structure and functionality has been including.

Aloe Vera extract-based composite nanofibers for wound dressing applications

Natural, biocompatible, and biodegradable composite nanofibers made of Aloe vera extract, pullulan, chitosan, and citric acid were successfully produced via Forcespinning® technology. The addition of Aloe vera extract at different weight percent loadings was investigated. The morphology, thermal properties, physical properties, and water absorption of the nanofibers were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The developed nanofiber membranes exhibited good water absorption capabilities, synergistic antibacterial activity against Escherichia coli, and promoted cell attachment and growth. Its porous and high surface area structure make it a potential candidate for wound dressing applications due to its ability to absorb excessive blood and exudates, as well as provide protection from infection while maintaining good thermal stability.

Synthesis and Characterization of Exopolysaccharide Encapsulated PCL/Gelatin Skin Substitute for Full-Thickness Wound Regeneration

Loss of skin integrity can lead to serious problems and even death. In this study, for the first time, the effect of exopolysaccharide (EPS) produced by cold-adapted yeast R. mucilaginosa sp. GUMS16 on a full-thickness wound in rats was evaluated. The GUMS16 strain's EPS was precipitated by adding cold ethanol and then lyophilized. Afterward, the EPS with polycaprolactone (PCL) and gelatin was fabricated into nanofibers with two single-needle and double-needle procedures. The rats' full-thickness wounds were treated with nanofibers and Hematoxylin and eosin (H&E) and Masson's Trichrome staining was done for studying the wound healing in rats. Obtained results from SEM, DLS, FTIR, and TGA showed that EPS has a carbohydrate chemical structure with an average diameter of 40 nm. Cell viability assessments showed that the 2% EPS loaded sample exhibits the highest cell activity. Moreover, in vivo implantation of nanofiber webs on the full-thickness wound on rat models displayed a faster healing rate when EPS was loaded into a nanofiber. These results suggest that the produced EPS can be used for skin tissue engineering applications.

Immunobiology and Application of Aloe Vera-Based Scaffolds in Tissue Engineering

Aloe vera (AV), a succulent plant belonging to the Liliaceae family, has been widely used for biomedical and pharmaceutical application. Its popularity stems from several of its bioactive components that have anti-oxidant, anti-microbial, anti-inflammatory and even immunomodulatory effects. Given such unique multi-modal biological impact, AV has been considered as a biomaterial for regenerative medicine and tissue engineering applications, where tissue repair and neo-angiogenesis are vital. This review outlines the growing scientific evidence that demonstrates the advantage of AV as tissue engineering scaffolds. We particularly highlight the recent advances in the application of AV-based scaffolds. From a tissue engineering perspective, it is pivotal that the implanted scaffolds strike an appropriate foreign body response to be well-accepted in the body without complications. Herein, we highlight the key cellular processes that regulate the foreign body response to implanted scaffolds and underline the immunomodulatory effects incurred by AV on the innate and adaptive system. Given that AV has several beneficial components, we discuss the importance of delving deeper into uncovering its action mechanism and thereby improving material design strategies for better tissue engineering constructs for biomedical applications.

Lanthanides-Substituted Hydroxyapatite/Aloe vera Composite Coated Titanium Plate for Bone Tissue Regeneration

PURPOSE

To develop the surface-treated metal implant with highly encouraged positive properties, including high anti-corrosiveness, bio-activeness and bio-compatibleness for orthopedic applications.

METHODS

In this work, the surface of commercially pure titanium (Ti) metal was treated with bio-compatible polydopamine (PD) by merely immersing the Ti plate in PD solution. The composite of trivalent lanthanide minerals (La3+, Ce3+ and Gd3+)-substituted hydroxyapatite (MHAP) with Aloe vera (AV) gel was prepared and coated on the PD-Ti plate by electrophoretic deposition (EPD) method. The choice of trivalent lanthanide ions is based on their bio-compatible nature and bone-seeking properties. The formation of the PD layer, composites, and composite coatings on Ti plate and PD-Ti surface was confirmed by FT-IR, XRD, SEM and HR-TEM observations. In-vitro assessments such as osteoblasts like MG-63 cell viability, alkaline phosphatase activity and mineralization ability of the MHAP/AV composite were tested, and the composite-coated plate was implanted into a rat bone defect model for in-vivo bone regeneration studies.

RESULTS

The coating ability of the MHAP/AV composite was highly preferred to PD-treated Ti plate than an untreated Ti plate due to the metal absorption ability of PD. This was confirmed by SEM analysis. The in-vitro and in-vivo studies show the better osteogenic ability of MHAP/AV composite at 14th day and 4th week of an experimental period, respectively.

CONCLUSION

The osteoblast ability of the fabricated device without producing any adverse effect in the rat model recommends that the fabricated device would serve as a better platform on the hard tissue regeneration for load-bearing applications of orthopedics.

Skin wound healing assisted by angiogenic targeted tissue engineering: A comprehensive review of bioengineered approaches

Skin injuries and in particular, chronic wounds, are one of the major prevalent medical problems, worldwide. Due to the pivotal role of angiogenesis in tissue regeneration, impaired angiogenesis can cause several complications during the wound healing process and skin regeneration. Therefore, induction or promotion of angiogenesis can be considered as a promising approach to accelerate wound healing. This article presents a comprehensive overview of current and emerging angiogenesis induction methods applied in several studies for skin regeneration, which are classified into the cell, growth factor, scaffold, and biological/chemical compound-based strategies. In addition, the advantages and disadvantages of these angiogenic strategies along with related research examples are discussed in order to demonstrate their potential in the treatment of wounds.

Fabrication of Promising Antimicrobial Aloe Vera/PVA Electrospun Nanofibers for Protective Clothing

In the present condition of COVID-19, the demand for antimicrobial products such as face masks and surgical gowns has increased. Because of this increasing demand, there is a need to conduct a study on the development of antimicrobial material. Therefore, this study was conducted on the development of Aloe Vera and Polyvinyl Alcohol (AV/PVA) electrospun nanofibers. Four different fibers were developed by varying the concentrations of Aloe vera (0.5%, 1.5%, 2.5%, and 3%) while maintaining the concentration of PVA constant. The developed samples were subjected to different characterization techniques such as SEM, FTIR, XRD, TGA, and ICP studies. After that, the antimicrobial activity of the developed Aloe Vera/PVA electrospun nanofibers was checked against Gram-positive (Staphylococcus aureus) bacteria and Gram-negative (Escherichia coli) bacteria. The developed nanofibers had high profile antibacterial activity against both bacteria, but showed excellent results against S. aureus bacteria as compared with E. coli. These nanofibers have potential applications in the development of surgical gowns, gloves, etc.

Nanofiber Technology for Regenerative Engineering

Regenerative engineering is powerfully emerging as a successful strategy for the regeneration of complex tissues and biological organs using a convergent approach that integrates several fields of expertise. This innovative and disruptive approach has spurred the demands for more choice of biomaterials with distinctive biological recognition properties. An ideal biomaterial is one that closely mimics the hierarchical architecture and features of the extracellular matrices (ECM) of native tissues. Nanofabrication technology presents an excellent springboard for the development of nanofiber scaffolds that can have positive interactions in the immediate cellular environment and stimulate specific regenerative cascades at the molecular level to yield healthy tissues. This paper systematically reviews the electrospinning process technology and its utility in matrix-based regenerative engineering, focusing mainly on musculoskeletal tissues. It briefly outlines the electrospinning/three-dimensional printing system duality and concludes with a discussion on the technology outlook and future directions of nanofiber matrices.

Polylactic acid-based electrospun fiber and hyaluronic acid-valsartan hydrogel scaffold for chronic wound healing

Background

In this study, the chronic wound healing ability of PLA-based electrospun nanofibers loaded with hyaluronic acid, valsartan, and ascorbic acid is explored. PLA-based scaffolds were fabricated by electrospinning, followed by loading the scaffolds with different concentrations of hyaluronic acid, valsartan, and ascorbic acid hydrogels. The produced formulations were characterized by scanning electron microscopy imaging (SEM), tensile strength testing, Fourier-transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). An in vitro drug release study was conducted to monitor the release of valsartan from the different formulations. This was followed by exploring the wound healing effects of the scaffolds in alloxan-induced diabetic rats and comparing the wound healing effects with positive and negative controls.

Results

The average diameter of the fibers was in the range of 300 to 490 nm with high porosity in the range of 63.90 to 79.44%, offering a large surface area-to-volume ratio, enhanced drug solubility, oxygen permeability, and fluid uptake. The presence of valsartan significantly impacted on the re-epithelization rate. Percentage re-epithelization rate was 31.2% ± 1.77% in the absence of treatment. Histologic section of tissue showed skin with underlying loose fibro-collagenous stroma (dermis) containing sebaceous glands and hair follicles for animals treated with VA, VB, VC, and VD. All the scaffolds reduced the number of inflammatory cell infiltrates at the wound site compared to the no treatment and conventionally treated groups. Conventional antibiotic treatment and VD (electrospun biomimetic scaffolds containing ascorbic acid) had % re-epithelization rates of 59.45% ± 1.69% and 62.01% ± 1.68% which were significantly lower than the PLA/HA-valsartan hydrogel scaffolds with VB having the highest % re-epithelization rate of 85.5% ± 1.7% (Figure 4B & 5C).

Conclusion

This study explored the use of biomimetic polylactic acid-based electrospun fiber and HA-valsartan hydrogel scaffold incorporating topical angiotensin receptor blockers to successfully accelerate wound healing. The novel PLA-based electrospun fibers loaded with hyaluronic acid-valsartan hydrogels were stable and possessed proven diabetic wound healing property. This was as a result of the known biomimetic effect of the fibers and increased re-epithelization facilitated by the hydrogels containing valsartan.

Graphical abstract

Aloe Vera-Derived Gel-Blended PHBV Nanofibrous Scaffold for Bone Tissue Engineering

Today, composite scaffolds fabricated by natural and synthetic polymers have attracted a lot of attention among researchers in the field of tissue engineering, and given their combined properties that can play a very useful role in repairing damaged tissues. In the current study, aloe vera-derived gel-blended poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofibrous scaffold was fabricated by electrospinning, and then, PHBV and PHBV gel fabricated scaffolds characterized by scanning electron microscope, protein adsorption, cell attachment, tensile and cell's viability tests. After that, osteogenic supportive property of the scaffolds was studied by culturing of human-induced pluripotent stem cells on the scaffolds under osteogenic medium and evaluating of the common bone-related markers. The results showed that biocompatibility of the PHBV nanofibrous scaffold significantly improved when combined with the aloe vera gel. In addition, higher amounts of alkaline phosphatase activity, mineralization, and bone-related gene and protein expression were detected in stem cells when grown on PHBV-gel scaffold in comparison with those stem cells grown on the PHBV and culture plate. Taken together, it can be concluded that aloe vera gel-blended PHBV scaffold has a great promising osteoinductive potential that can be used as a suitable bioimplant for bone tissue engineering applications to accelerate bone regeneration and also degraded completely along with tissue regeneration.

Incorporation of phytochemicals into electrospun scaffolds for wound-healing applications in vitro and in vivo

Despite advances in wound treatment, wound-associated infections and delayed healing still remains an ‘unmet clinical need’. The present treatment modalities include topical application of ointments and perhaps it may better be substituted by phytochemical incorporated nanofibers which increases wound-healing efficiency and reduce risk of infections. Hence, the aim of this study was to synthesise Areca catechu–incorporated polycaprolactone scaffolds for wound-healing applications. In this study, the tender nut of Areca catechu plant was collected and extracted with ethanol using the maceration technique. The presence of various active phytochemical constituents of ethanolic fraction of Areca catechu like phenol, flavonoid, tannin and alkaloid were identified qualitatively and estimated quantitatively. Areca catechu incorporated 10%w/w polycaprolactone scaffolds were fabricated by electrospinning technique and characterised physico-chemically by Fourier-transform infrared spectroscopy and scanning electron microscope analysis. In vitro cytotoxicity analysis was evaluated with L929 fibroblasts and in vivo wound-healing studies using rat models for both polycaprolactone and Areca catechu–incorporated polycaprolactone scaffolds. Extract of Areca catechu exhibited antioxidant properties and antibacterial activity against Staphylococcus aureus and Psuedomonus aeru ginosa. Scanning electron microscope image revealed the nanofibrous structural morphology of Areca catechu–incorporated polycaprolactone and polycaprolactone with average diameter of 350 and 399 nm, respectively. The characteristic peak of Fourier-transform infrared spectroscopy depicted the presence of biomolecules and detection of functional groups confirming the incorporation of Areca catechu into the polycaprolactone scaffold. Furthermore, cells were cytocompatible with 85% viability over Areca catechu–incorporated polycaprolactone scaffolds, and wounds treated with Areca catechu–incorporated polycaprolactone healed faster with a significant difference in the wound area than polycaprolactone controls. The phytochemical-incorporated polycaprolactone scaffolds with antioxidant, antimicrobial, biocompatible and wound-healing properties is proposed to be an indigenous approach towards wound care management globally and seems to be better and cost-effective wound dressings.

A promising wound dressing based on alginate hydrogels containing vitamin D3 cross-linked by calcium carbonate/d-glucono-δ-lactone

In the present study, we fabricated vitamin D₃-loaded alginate hydrogel and assessed its wound healing capability in the animal model. The various concentrations of vitamin D3 were added to the pre-dissolved sodium alginate in deionized water and cross-linked by calcium carbonate in combination with d-glucono-δ-lactone. The microstructure, swelling behavior, weight loss, hemo- and cytocompatibility of the fabricated hydrogels were evaluated. In the last stage, the therapeutic efficacy of the prepared hydrogels was evaluated in the full-thickness dermal wound model. The scanning electron microscopy images showed that the prepared hydrogel was highly porous with the porosity of 89.2 ± 12.5% and contained the interconnected pores. Weight loss assessment showed that the prepared hydrogel is biodegradable with the weight loss percentage of about 89% in 14 days. The results showed that the prepared hydrogels were hemo- and cytocompatible. The animal study results implied that alginate hydrogel/3000 IU vitamin D₃ group exhibited the highest wound closure present which was statistically significant than the control group (p < 0.05). Moreover, the histological examinations revealed that hydrogel containing 3000 IU vitamin D3 had the best performance and induced the highest re-epithelialization and granular tissue formation. All in all, this study suggests that alginate hydrogels with 3000 IU vitamin D₃ can be exploited as a potential wound dressing in skin tissue engineering.

Antithrombogenic properties of Tulbaghia violacea–loaded polycaprolactone nanofibers

A broad range of polymers have been utilized for the development of blood-contacting implantable medical devices; however, their rate of failure has raised the need for developing more hemocompatible biomaterial surfaces. In this study, a novel scaffold based on polycaprolactone incorporated with 10% and 15% (w/w) Tulbaghia violacea plant extracts were fabricated using electrospinning technique. The fabricated scaffolds were then treated with T. violacea aqueous plant extracts (100 and 1000 µg/mL) to investigate their use as interfaces for blood-contacting implants. The 10% Tvio scaffold produced the lowest mean fibre diameter (193 ± 30 nm), whereas the 15% Tvio scaffold produces the highest mean fibre diameter (538 ± 236 nm) when compared with the control polycaprolactone (275 ± 61 nm) scaffold. The number of adhered platelets was directly linked to fibre diameter and concentration of plant extract in such a way that the lowest fibre diameter scaffold (10% Tvio) inhibited platelet adhesion, whereas more platelets adhered to the scaffold with the highest fibre diameter (15% Tvio scaffolds). There was also an increase in platelet adhesion as the concentration of T. violacea was increased from 100 to 1000 µg/mL for all designed scaffolds. The improved blood compatibility demonstrated by the 10% Tvio scaffold suggests that the plant possesses antithrombogenic properties, particularly at lower concentrations.

A novel egg-shell membrane based hybrid nanofibrous scaffold for cutaneous tissue engineering

Background

The main issue in cutaneous regeneration is to develop engineered scaffolds based on natural extracellular matrix to promote dynamics of skin progenitor cells and accelerate differentiation into mature keratinocytes.

Methods

In this study, nanofibrous scaffolds composed of a blend poly (ɛ-caprolactone) (PCL), silk fibroin (SF), soluble eggshell membrane (SESM), and Aloe vera (AV) gel were developed by electrospinning method and human basal cells were used to examine differentiation capacity toward keratinocyte-like cells. For this propose, cells were allocated to four distinct groups; control, PCL/SF, PCL/SF/SESM, and PCL/SF/SESM/AV. In all groups, cells were incubated with differentiation medium. Morphology, composition, hydrophilicity and mechanical features of PCL/SF, PCL/SF/SESM and PCL/SF/SESM/AV nanofibers were studied by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), water contact angle and tensile tests. To examine the orientation of basal cells to mature keratinocytes, we performed immunofluorescence analysis by monitoring cytokeratin-19. The expression of genes such as involucrin, keratin-14 and -5 was monitored by real-time PCR assay.

Results

PCL/SF, PCL/SF/SESM, and PCL/SF/SESM/AV had suitable physic chemical indices and biological activities to be applied as biomimetic scaffolds for the restoration cutaneous tissue. Compared to control, we found an increased basal cell proliferation at 7 and 14 days after plating on scaffolds and reach maximum levels in group PCL/SF/SESM/AV on day 14 (p < 0.05). Electron microscopy showed cell flattening, morphological adaptation. An integrated cell-to-cell connection was generated after cell seeding on scaffolds in all groups. Immunofluorescence imaging showed the ability of basal cells to synthesize cytokeratin-19 in PCL/SF, PCL/SF/SESM, and positive control cells after exposure to differentiation medium. However, these values were less in PCL/SF/SESM/AV compared to other groups. Real-time PCR analysis showed the potency of all scaffolds to induce the transcription of involucrin, keratin-14 and -5, especially involucrin in PCL/SF/SESM/AV group compared to the negative control.

Conclusion

Modulation of scaffolds with natural biopolymers could enable us to synthesize structures appropriate for cutaneous regeneration.

Biocompatible Aloe vera and Tetracycline Hydrochloride Loaded Hybrid Nanofibrous Scaffolds for Skin Tissue Engineering

Aloe vera (AV) and tetracycline hydrochloride (TCH) exhibit significant properties such as anti-inflammatory, antioxidant and anti-bacterial activities to facilitate skin tissue engineering. The present study aims to develop poly-ε-caprolactone (PCL)/ AV containing curcumin (CUR), and TCH loaded hybrid nanofibrous scaffolds to validate the synergistic effect on the fibroblast proliferation and antimicrobial activity against Gram-positive and Gram-negative bacteria for wound healing. PCL/AV, PCL/CUR, PCL/AV/CUR and PCL/AV/TCH hybrid nanofibrous mats were fabricated using an electrospinning technique and were characterized for surface morphology, the successful incorporation of active compounds, hydrophilicity and the mechanical property of nanofibers. SEM revealed that there was a decrease in the fiber diameter (ranging from 360 to 770 nm) upon the addition of AV, CUR and TCH in PCL nanofibers, which were randomly oriented with bead free morphology. FTIR spectra of various electrospun samples confirmed the successful incorporation of AV, CUR and TCH into the PCL nanofibers. The fabricated nanofibrous scaffolds possessed mechanical properties within the range of human skin. The biocompatibility of electrospun nanofibrous scaffolds were evaluated on primary human dermal fibroblasts (hDF) by MTS assay, CMFDA, Sirius red and F-actin stainings. The results showed that the fabricated PCL/AV/CUR and PCL/AV/TCH nanofibrous scaffolds were non-toxic and had the potential for wound healing applications. The disc diffusion assay confirmed that the electrospun nanofibrous scaffolds possessed antibacterial activity and provided an effective wound dressing for skin tissue engineering.

Status of Plant Protein-Based Green Scaffolds for Regenerative Medicine Applications

In recent decades, regenerative medicine has merited substantial attention from scientific and research communities. One of the essential requirements for this new strategy in medicine is the production of biocompatible and biodegradable scaffolds with desirable geometric structures and mechanical properties. Despite such promise, it appears that regenerative medicine is the last field to embrace green, or environmentally-friendly, processes, as many traditional tissue engineering materials employ toxic solvents and polymers that are clearly not environmentally friendly. Scaffolds fabricated from plant proteins (for example, zein, soy protein, and wheat gluten), possess proper mechanical properties, remarkable biocompatibility and aqueous stability which make them appropriate green biomaterials for regenerative medicine applications. The use of plant-derived proteins in regenerative medicine has been especially inspired by green medicine, which is the use of environmentally friendly materials in medicine. In the current review paper, the literature is reviewed and summarized for the applicability of plant proteins as biopolymer materials for several green regenerative medicine and tissue engineering applications.

3D bioprinted endometrial stem cells on melt electrospun poly ε-caprolactone mesh for pelvic floor application promote anti-inflammatory responses in mice

Endometrial mesenchymal stem/stromal cells (eMSCs) exhibit excellent regenerative capacity in the endometrial lining of the uterus following menstruation and high proliferative capacity in vitro. Bioprinting eMSCs onto a mesh could be a potential therapy for Pelvic Organ Prolapse (POP). This study reports an alternative treatment strategy targeting vaginal wall repair using bioprinting of eMSCs encapsulated in a hydrogel and 3D melt electrospun mesh to generate a tissue engineering construct. Following a CAD, 3D printed poly ε-caprolactone (PCL) meshes were fabricated using melt electrospinning (MES) at different temperatures using a GMP clinical grade GESIM Bioscaffolder. Electron and atomic force microscopies revealed that MES meshes fabricated at 100 °C and with a speed 20 mm/s had the largest open pore diameter (47.2 ± 11.4 μm) and the lowest strand thickness (121.4 ± 46 μm) that promoted optimal eMSC attachment. An Aloe Vera-Sodium Alginate (AV-ALG) composite based hydrogel was optimised to a 1:1 mixture (1%AV-1%ALG) and eMSCs, purified from human endometrial biopsies, were then bioprinted in this hydrogel onto the MES printed meshes. Acute in vivo foreign body response assessment in NSG mice revealed that eMSC printed on MES constructs promoted tissue integration, eMSC retention and an anti-inflammatory M2 macrophage phenotype characterised by F4/80⁺CD206⁺ colocalization. Our results address an unmet medical need highlighting the potential of 3D bioprinted eMSC-MES meshes as an alternative approach to overcome the current challenges with non-degradable knitted meshes in POP treatment. STATEMENT OF SIGNIFICANCE: This study presents the first report of bioprinting mesenchymal stem cells derived from woman endometrium (eMSCs) to boost Pelvic Organ Prolapse (POP) treatment. It impacts over 50% of elderly women with no optimal treatment at present. The overall study is conducted in three stages as fabricating a melt electrospun (MES) mesh, bioprinting eMSCs into a Ca²⁺ free Aloe Vera-Alginate (AV-Alg) based hydrogel and in vivo study. Our data showed that AV-ALG hydrogel potentially suppresses the foreign body response and further addition of eMSCs triggered a high influx of anti-inflammatory CD206⁺ M2 macrophages. Our final construct demonstrates a favourable foreign body response to predict expected tissue integration, therefore, provides a potential for developing an alternative treatment for POP.

Histological, immunohistochemical, and genomic evaluation of excisional and diabetic wounds treated with human Wharton's jelly stem cells with and without a nanocarrier

We showed in previous studies that human umbilical cord Wharton's jelly stem cells (hWJSCs) improved the healing rates of excisional and diabetic wounds in the mouse model. As an extension of those studies, we report here the more detailed quantitative histological, immunohistochemical, and genomic evaluation of biopsies from those excisional and diabetic wounds in an attempt to understand the mechanisms of the enhanced wound healing aided by hWJSCs. Bright-field microscopic observations and ImageJ software analysis on histological sections of the excisional and diabetic wound biopsies collected at different time points showed that the thickness of the epidermis and dermis, and positive picrosirius-red stained areas for collagen, were significantly greater in the presence of hWJSCs compared with controls (P < 0.05). Immunohistochemistry of the diabetic wound biopsies showed increased positive staining for the vascular endothelial marker CD31 and cell proliferation marker Ki67 in the presence of hWJSCs and its conditioned medium (hWJSC-CM). Quantitative real-time polymerase chain reaction showed upregulation of groups of genes involved in extracellular matrix regulation, collagen biosynthesis, angiogenesis, antifibrosis, granulation, and immunomodulation in the presence of hWJSCs. Taken together, the results demonstrated that hWJSCs and hWJSC-CM that contains the paracrine secretions of hWJSCs, enhance the healing of excisional and diabetic wounds via re-epithelialization, collagen deposition, angiogenesis, and immunomodulation. The inclusion of an Aloe vera-polycaprolactone (AV/PCL) nanocarrier did not significantly change the effect of the hWJSCs. However, the topical application of an AV/PCL nanocarrier impregnated with hWJSCs is convenient and less invasive than the administration of hWJSC injections into wounds.

Improved Multicellular Response, Biomimetic Mineralization, Angiogenesis, and Reduced Foreign Body Response of Modified Polydioxanone Scaffolds for Skeletal Tissue Regeneration

The potential of electrospun polydioxanone (PDX) mats as scaffolds for skeletal tissue regeneration was significantly enhanced through improvement of the cell-mediated biomimetic mineralization and multicellular response. This was achieved by blending PDX ( i) with poly(hydroxybutyrate- co-valerate) (PHBV) in the presence of hydroxyapatite (HA) and ( ii) with aloe vera (AV) extract containing a mixture of acemannan/glucomannan. In an exhaustive study, the behavior of the most relevant cell lines involved in the skeletal tissue healing cascade, i.e. fibroblasts, macrophages, endothelial cells and preosteoblasts, on the scaffolds was investigated. The scaffolds were shown to be nontoxic, to exhibit insignificant inflammatory responses in macrophages, and to be degradable by macrophage-secreted enzymes. As a result of different phase separation in PDX/PHBV/HA and PDX/AV blend mats, cells interacted differentially. Presumably due to varying tension states of cell-matrix interactions, thinner microtubules and significantly more cell adhesion sites and filopodia were formed on PDX/AV compared to PDX/PHBV/HA. While PDX/PHBV/HA supported micrometer-sized spherical particles, nanosized rod-like HA was observed to nucleate and grow on PDX/AV fibers, allowing the mineralized PDX/AV scaffold to retain its porosity over a longer time for cellular infiltration. Finally, PDX/AV exhibited better in vivo biocompatibility compared to PDX/PHBV/HA, as indicated by the reduced fibrous capsule thickness and enhanced blood vessel formation. Overall, PDX/AV blend mats showed a significantly enhanced potential for skeletal tissue regeneration compared to the already promising PDX/PHBV/HA blends.

Fabrication and Characterization of Core-Shell Electrospun Fibrous Mats Containing Medicinal Herbs for Wound Healing and Skin Tissue Engineering

Nanofibrous structures mimicking the native extracellular matrix have attracted considerable attention for biomedical applications. The present study aims to design and produce drug-eluting core-shell fibrous scaffolds for wound healing and skin tissue engineering. Aloe vera extracts were encapsulated inside polymer fibers containing chitosan, polycaprolactone, and keratin using the co-axial electrospinning technique. Electron microscopic studies show that continuous and uniform fibers with an average diameter of 209 ± 47 nm were successfully fabricated. The fibers have a core-shell structure with a shell thickness of about 90 nm, as confirmed by transmission electron microscopy. By employing Fourier-transform infrared spectroscopy, the characteristic peaks of Aloe vera were detected, which indicate successful incorporation of this natural herb into the polymeric fibers. Tensile testing and hydrophilicity measurements indicated an ultimate strength of 5.3 MPa (elongation of 0.63%) and water contact angle of 89°. In-vitro biological assay revealed increased cellular growth and adhesion with the presence of Aloe vera without any cytotoxic effects. The prepared core-shell fibrous mats containing medical herbs have a great potential for wound healing applications.

Starch nanoparticle as a vitamin E-TPGS carrier loaded in silk fibroin-poly(vinyl alcohol)-Aloe vera nanofibrous dressing

Core-sheath nanofibrous mat as a new vitamin E (VE) delivery system based on silk fibroin (SF)/poly(vinyl alcohol) (PVA)/aloe vera (AV) was successfully prepared by the electrospinning method. Initially, VE-loaded starch nanoparticles were produced and then incorporated into the best beadless SF-PVA-AV nanofibers. The successful loading of VE in starch nanoparticles was proved by Fourier-transform infrared spectroscopy. The scanning electron microscopy and transmission electron microscopy indicated that spherical nanoparticles were successfully embedded within the nanofibers. In vitro release studies demonstrated that the release of VE was controlled by Fickian diffusion and was faster in samples containing more nanoparticles. Fibroblast attachment, proliferation, and collagen secretion were enhanced after adding AV and VE to the SF-PVA nanomatrix. Moreover, the incorporation of VE into the nanocomposite dressing enhanced antioxidant activity, which can have a positive effect on wound healing process by protecting the cells from toxic oxidation products.

Encapsulation of Bioactive Compound in Electrospun Fibers and Its Potential Application

Electrospinning is a simple and versatile encapsulation technology. Since electrospinning does not involve severe conditions of temperature or pressure or the use of harsh chemicals, it has great potential for effectively entrapping and delivering bioactive compounds. Recently, electrospinning has been used in the food industry to encapsulate bioactive compounds into different biopolymers (carbohydrates and proteins), protecting them from adverse environmental conditions, maintaining the health-promoting properties, and achieving their controlled release. Electrospinning opens a new horizon in food technology with possible commercialization in the near future. This review summarizes the principles and the types of electrospinning processes. The electrospinning of biopolymers and their application in encapsulating of bioactive compounds are highlighted. The existing scope, limitations, and future prospects of electrospinning bioactive compounds are also presented.

Macrophage repolarization using emu oil-based electrospun nanofibers: possible application in regenerative medicine

In the regenerative medicine therapies, the availability of engineered scaffolds that modulate inflammatory states is highly required. The aim of this study was to evaluate the efficiency of electrospun nanofibrous scaffolds containing natural substances with anti-inflammatory properties such as Emu oil (EO) to control inflammation and re-polarization of macrophages toward M2 anti-inflammatory phonotype. For this purpose, bead free and smooth EO-blended PCL/PEG electrospun nanofibrous mats were successfully fabricated and characterized using FE-SEM, FTIR, and Universal Testing Machine. GC/MS findings of pure EO revealed the fatty acids composition. MTT results showed that macrophage viability on EO-PCL/PEG nanofibres was higher than on PCL/PEG nanofibres and control (p ≤ .05). Additionally, the presence of EO into nanofibres was found to influence on macrophage morphologies, using FE-SEM. qPCR results showed a reduction in iNOS-2 and an increase in Arg-1 levels of macrophages seeded on EO-PCL/PEG nanofibres, indicating the successfully polarization of the macrophages to M2 phenotype. The change in macrophage phenotype on EO-based nanofibres could suppress the inflammation in LPS/IFN-γ stimulated macrophages as evidenced by a major reduction in pro-inflammatory cytokine levels TNF-α, IL-1β, and IL-6. Conclusively, the results demonstrated that EO-based nanofibres efficiently modulated RAW264.7 macrophage polarity toward an anti-inflammatory M2 phenotype.

Fabrication and Characterization of Magnesium Ferrite-Based PCL/Aloe Vera Nanofibers

Composite nanofibers of biopolymers and inorganic materials have been widely explored as tissue engineering scaffolds because of their superior structural, mechanical and biological properties. In this study, magnesium ferrite (Mg-ferrite) based composite nanofibers were synthesized using an electrospinning technique. Mg-ferrite nanoparticles were first synthesized using the reverse micelle method, and then blended in a mixture of polycaprolactone (PCL), a synthetic polymer, and Aloe vera, a natural polymer, to create magnetic nanofibers by electrospinning. The morphology, structural and magnetic properties, and cellular compatibility of the magnetic nanofibers were analyzed. Mg-ferrite/PCL/Aloe vera nanofibers showed good uniformity in fiber morphology, retained their structural integrity, and displayed magnetic strength. Experimental results, using cell viability assay and scanning electron microscopy imaging showed that magnetic nanofibers supported 3T3 cell viability. We believe that the new composite nanofibrous membranes developed in this study have the ability to mimic the physical structure and function of tissue extracellular matrix, as well as provide the magnetic and soluble metal ion attributes in the scaffolds with enhanced cell attachment, and thus improve tissue regeneration.

Electrospun Collagen Nanofibers and Their Applications in Skin Tissue Engineering

Electrospinning is a simple and versatile technique to fabricate continuous fibers with diameter ranging from micrometers to a few nanometers. To date, the number of polymers that have been electrospun has exceeded 200. In recent years, electrospinning has become one of the most popular scaffold fabrication techniques to prepare nanofiber mesh for tissue engineering applications. Collagen, the most abundant extracellular matrix protein in the human body, has been electrospun to fabricate biomimetic scaffolds that imitate the architecture of native human tissues. As collagen nanofibers are mechanically weak in nature, it is commonly cross-linked or blended with synthetic polymers to improve the mechanical strength without compromising the biological activity. Electrospun collagen nanofiber mesh has high surface area to volume ratio, tunable diameter and porosity, and excellent biological activity to regulate cell function and tissue formation. Due to these advantages, collagen nanofibers have been tested for the regeneration of a myriad of tissues and organs. In this review, we gave an overview of electrospinning, encompassing the history, the instrument settings, the spinning process and the parameters that affect fiber formation, with emphasis given to collagen nanofibers' fabrication and application, especially the use of collagen nanofibers in skin tissue engineering.

Development of a membrane of poly (L-co-D,L lactic acid-co-trimethylene carbonate) with aloe vera: An alternative biomaterial designed to improve skin healing

The search for new therapies and drugs that act as topical agents to relieve pain and control the infectious processes in burns always attracted interest in clinical trials. As an alternative to synthetic drugs, the use of natural extracts is useful in the development of new strategies and formulations for improving the life quality. The aim of this study was to develop a wound dressing using Poly(L-co-D,L lactic acid-co-TMC) (PLDLA-co-TMC) containing aloe vera (AV). This natural plant extract is known for its modulatory effects under healing process. The membrane of PLDLA-co-TMC+aloe vera was prepared at different concentrations of AV (5, 10, 15 and 50%). The FTIR showed no change in the PLDLA-co-TMC spectrum after AV addition, while the swelling test showed changes only in PLDLA-co-TMC+AV at 50%. The wettability measurements showed decrease in the contact angle in all samples after the AV addition in the polymer, while the AV release test showed that PLDLA-co-TMC+50%AV sample has higher AV release rate than the sample with other AV concentrations. The SEM analysis showed that AV was homogeneously distributed at 5% only. Tensile tests demonstrated an increase in the Young's modulus and a reduction in the elongation till rupture of the PLDLA-co-TMC after the addition of AV. Biocompatibility in vitro evaluation with fibroblast cells seeded in the membranes of PLDLA-co-TMC+AV showed that the cells were able to adhere, proliferate and maintain mitochondrial activity in all AV concentrations tested. Due to the known skin medicinal properties attributed to AV and the results here obtained, we suggest that after in vivo trials, the PLDLA-co-TMC+AV should be a promising biomaterial for application as a device for skin curative and healing agent.

Electrospun Polycaprolactone/Aloe Vera_Chitosan Nanofibrous Asymmetric Membranes Aimed for Wound Healing Applications

Today, none of the wound dressings available on the market is fully capable of reproducing all the features of native skin. Herein, an asymmetric electrospun membrane was produced to mimic both layers of skin. It comprises a top dense layer (manufactured with polycaprolactone) that was designed to provide mechanical support to the wound and a bottom porous layer (composed of chitosan and Aloe Vera) aimed to improve the bactericidal activity of the membrane and ultimately the healing process. The results obtained revealed that the produced asymmetric membranes displayed a porosity, wettability, as well as mechanical properties similar to those presented by the native skin. Fibroblast cells were able to adhere, spread, and proliferate on the surface of the membranes and the intrinsic structure of the two layers of the membrane is capable of avoiding the invasion of microorganisms while conferring bioactive properties. Such data reveals the potential of these asymmetric membranes, in the near future, to be applied as wound dressings.

Cytoprotection, proliferation and epidermal differentiation of adipose tissue-derived stem cells on emu oil based electrospun nanofibrous mat

Electrospun nanofibrous scaffolds containing natural substances with wound healing properties such as Emu oil (EO) may have a great potential for increasing the efficiency of stem cell-based skin bioengineering. For this purpose, EO blended PCL/PEG electrospun nanofibrous mats were successfully fabricated and characterized using FE-SEM, FTIR and Universal Testing Machine. The efficiency of the scaffolds in supporting the adherence, cytoprotection, proliferation and differentiation of adipose tissue-derived stem cells (ADSCs) to keratinocyte was evaluated. GC/MS and HPLC were used to determine the composition of pure EO, which revealed to be mainly fatty acids and carotenoids. FE-SEM and cell proliferation assays showed that adhesion and proliferation of ADSCs on EO-PCL/PEG nanofibers was significantly higher than on PCL/PEG nanofibers. Additionally, EO-PCL/PEG nanofibers with free radical scavenging properties conferred a cytoprotective effect against cell-damaging free radicals, while the ability to support cell adhesion and growth was maintained or even improved. Immunostaining of ADSCs on EO-PCL/PEG nanofibers confirmed the change in morphology of ADSCs from spindle to polygonal shape suggesting their differentiation toward an epidermal linage. Moreover, the expression levels of the keratin 10, filaggrin, and involucrin that are involved in epidermal differentiation were upregulated in a stage-specific manner. This preliminary study shows that EO-PCL/PEG nanofibers could be a good candidate for the fabrication of wound dressings and skin bioengineered substitutes with ADSCs.

Aloe Vera for Tissue Engineering Applications

Aloe vera, also referred as Aloe barbadensis Miller, is a succulent plant widely used for biomedical, pharmaceutical and cosmetic applications. Aloe vera has been used for thousands of years. However, recent significant advances have been made in the development of aloe vera for tissue engineering applications. Aloe vera has received considerable attention in tissue engineering due to its biodegradability, biocompatibility, and low toxicity properties. Aloe vera has been reported to have many biologically active components. The bioactive components of aloe vera have effective antibacterial, anti-inflammatory, antioxidant, and immune-modulatory effects that promote both tissue regeneration and growth. The aloe vera plant, its bioactive components, extraction and processing, and tissue engineering prospects are reviewed in this article. The use of aloe vera as tissue engineering scaffolds, gels, and films is discussed, with a special focus on electrospun nanofibers.