Nowadays, despite the intensive research performed in the area of skin tissue engineering, the treatment of skin lesions remains a big challenge for healthcare professionals. In fact, none of the wound dressings currently used in the clinic is capable of re-establishing all the native features of skin. An ideal wound dressing must confer protection to the wound from external microorganisms, chemical, and physical aggressions, as well as promote the healing process by stimulating the cell adhesion, differentiation, and proliferation. In recent years different types of wound dressings (such as films, hydrocolloids, hydrogels, micro/nano fibers) have been developed. Among them, electrospun nanofibrous membranes due to their intrinsic properties like high surface area-to-volume ratio, porosity and structural similarity with the skin extracellular matrix have been regarded as highly promising for wound dressings applications. Additionally, the nanofibers available in these membranes can act as drug delivery systems, which prompted the incorporation of biomolecules within their structure to prevent skin infections as well as improve the healing process. In this review, examples of different bioactive molecules that have been loaded on polymeric nanofibers are presented, highlighting the antibacterial biomolecules (e.g. antibiotics, silver nanoparticles and natural extracts-derived products) and the molecules capable of enhancing the healing process (e.g. growth factors, vitamins, and anti-inflammatory molecules).

The wound healing process involves highly complex and dynamic events that allow the re-establishment of skin's structural integrity. To further improve or to overcome the drawbacks associated with this process, researchers have been focused on the development of new therapeutics. Among them, asymmetric membranes are currently one of the most promising approaches to be used in wound healing due to its structural similarities with the epidermal and dermal layers of the native skin. The outer layer of asymmetric membranes provides a barrier that protects the wound from external damages (e.g. microorganisms and chemical agents), whereas the interior porous layer acts as template for supporting cell adhesion, migration and proliferation. Among the different materials used to produce these distinct layers, the chitosan arises as one of the preeminent materials due to its inherent biocompatibility, antibacterial, hemostatic, and healing properties. Therefore, in this review, it is provided an overview of the different chitosan-based asymmetric membranes developed for wound dressing applications. Further, the chitosan modifications to enhance its bioactivity as well as the asymmetric membranes general properties and production techniques are also described.

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.

Skin is a complex organ that act as the first protective barrier against any external threat. After an injury occurs, its structure and functions must be re-established as soon as possible. Among different available skin substitutes (epidermal, dermal and dermo-epidermal), none of them is fully capable of reproducing/re-establishing all the features and functions of native skin. Herein, a three-dimensional skin asymmetric construct (3D_SAC) was produced using electrospinning and 3D bioprinting techniques. A poly(caprolactone) and silk sericin blend was electrospun to produce a top layer aimed to mimic the epidermis features, i.e. to provide a protective barrier against dehydration and hazard agents. In turn, the dermis like layer was formed by printing layer-by-layer a chitosan/sodium alginate hydrogel. The results obtained in the in vitro assays revealed that the 3D_SAC display a morphology, porosity, mechanical properties, wettability, antimicrobial activity and a cytotoxic profile that grants their application as a skin substitute during the healing process.

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.

Skin lesions are traumatic events that lead to increased fluid loss, infections, scars formation and the appearance of immunocompromised regions. The loss of skin integrity can result in significant physiological imbalances and disability or even death. So far, different wound dressings have been developed. Among them, hydrogels are the most applied. Herein, a thermoresponsive hydrogel was produced using chitosan and agarose formed at body temperature (37°C), in order to verify their applicability in the treatment of wounds. Hydrogel bactericidal activity, biocompatibility, morphology, porosity and wettability were characterized by confocal microscopy, MTS assay and SEM. The attained results revealed that hydrogel has a pore size (90–400 µm) compatible with cellular internalization and proliferation. A bactericidal activity was observed for hydrogels containing more than 188 µg/mL of chitosan. The results obtained demonstrated that this 3D network has the suitable properties for improving the healing process of cutaneous wounds.

Skin wounds have significant morbidity and mortality rates associated. This is explained by the limited effectiveness of the currently available treatments, which in some cases do not allow the reestablishment of the structure and functions of the damaged skin, leading to wound infection and dehydration. These drawbacks may have an impact on the healing process and ultimately prompt patients’ death. For this reason, researchers are currently developing new wound dressings that enhance skin regeneration. Among them, electrospun polymeric nanofibres have been regarded as promising tools for improving skin regeneration due to their structural similarity with the extracellular matrix of normal skin, capacity to promote cell growth and proliferation and bactericidal activity as well as suitability to deliver bioactive molecules to the wound site. In this review, an overview of the recent studies concerning the production and evaluation of electrospun polymeric nanofibrous membranes for skin regenerative purposes is provided. Moreover, the current challenges and future perspectives of electrospun nanofibrous membranes suitable for this biomedical application are highlighted.

Healing enhancement and pain control are critical issues on wound management. So far, different wound dressings have been developed. Among them, hydrogels are the most applied. Herein, a thermoresponsive hydrogel was produced using chitosan (deacetylation degree 95%) and agarose. Hydrogel bactericidal activity, biocompatibility, morphology, porosity and wettability were characterized by confocal microscopy, MTS assay and SEM. The performance of the hydrogel in the wound healing process was evaluated through in vivo assays, during 21 days. The attained results revealed that hydrogel has a pore size (90–400 μm) compatible with cellular internalization and proliferation. A bactericidal activity was observed for hydrogels containing more than 188 μg/mL of chitosan. The improved healing and the lack of a reactive or a granulomatous inflammatory reaction in skin lesions treated with hydrogel demonstrate its suitability to be used in a near future as a wound dressing.

Nowadays, wound dressings with improved properties are under development and among them, asymmetric membranes have gained an increasing interest due to their two-layered structure that mimic both the epidermis and dermis layers of the skin. Herein, a new asymmetric membrane was produced using the electrospinning technique. The top layer was produced with silk fibroin (SF) and poly(caprolactone) to reproduce the dense nature and waterproof ability of the epidermis. On the other hand, the dermis-like bottom layer was manufactured with SF and hyaluronic acid loaded with an herbal drug (thymol (THY)). All the data gathered showed that the produced electrospun asymmetric membrane exhibited the porosity, wettability, and mechanical properties suitable for the healing process. Further, the in vitro data also demonstrated that the human fibroblast is able to adhere and spread at the membranes' surface, thus confirming their biocompatibility. Moreover, the incorporation of THY into the bottom layer of the membrane, improved its antioxidant and antibacterial properties. Overall, the obtained results demonstrate the appropriateness of the produced membrane for wound healing applications.

This article discusses the feminist publication field constituted by the nongovernmental organizations production and the academic and editorial production, done by the Universities, through its gender and/or women studies nucleus, gender subjects in different courses. The article, based in the Feminist Center for Studies and Advisory Services – CFEMEA editorial experience, analyses the editorial production of the feminist NGOs and its divulgation.