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- Electrospun polymeric nanofibres as wound dressings: A reviewPublication . Miguel, Sónia P.; Figueira, Daniela Sofia Rodrigues; Simões, Déborah; Ribeiro, MP.; Coutinho, Paula; Ferreira, Paula; Correia, Ilídio Joaquim SobreiraSkin 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.
- Photocrosslinkable electrospun fiber meshes for tissue engineering applicationsPublication . Ferreira, Paula; Santos, Patrícia; Alves, P.; Carvalho, Marco António Paulo de; Sá, Kevin; Miguel, Sónia P.; Correia, Ilídio Joaquim Sobreira; Coimbra, Patrícia Manuela AlmeidaElectrospun polymeric meshes are known to exhibit promising properties for the regeneration of several soft tissues. Herein, electrospun polymeric meshes were prepared from blends of polycaprolactone and functionalized gelatin. The meshes were then photocrosslinked under UV light using Irgacure® 2959 as the photoinitiator, aiming to improve membranes’ stability in biological fluids. Moreover, meshes suitability to be used as vascular grafts was evaluated by characterizing their chemical/physical properties as well as their haemo and biocompatibility in vitro. The obtained results show that the blended polymeric meshes are biodegradable and those with a higher content of gelatin display a lower water contact angle. Blood compatibility studies showed that the photocrosslinked membranes are haemocompatible, i.e. they display low values of thrombogenicity and do not trigger any haemolytic effect. Also, Normal Human Dermal Fibroblasts cells were incubated in the presence of the produced membranes and they were able to adhere and proliferate, thus revealing the biocompatibility of the photocrosslinked meshes.
- 3D scaffolds coated with nanofibers displaying bactericidal activity for bone tissue applicationsPublication . Sá, Kevin; Figueira, Daniela Sofia Rodrigues; Miguel, Sónia P.; Correia, Tiago R.; Silva, Abílio Manuel Pereira da; Correia, I.J.Bone-limited capacity to fully repair large defects requires the development of new implants. In this context, new approaches have been used to promote bone regeneration and also to avoid the side effects associated with the therapeutics currently used in the clinic. Herein, 3D tricalcium phosphate/alginic acid scaffolds were produced and then coated with an electrospun mesh loaded with two different antibacterial agents, silver nanoparticles, and salicylic acid. The obtained results showed that the produced scaffolds have suitable mechanical properties, swelling, biodegradation, biomineralization activity, enhanced cellular adhesion/proliferation and bactericidal activity, and features essential for bone regeneration.
- Production and characterization of a novel asymmetric 3D printed construct aimed for skin tissue regenerationPublication . Miguel, Sónia; Cabral, Cátia S. D.; Moreira, André; Correia, I.J.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.
- Electrospun Polycaprolactone/Aloe Vera_Chitosan Nanofibrous Asymmetric Membranes Aimed for Wound Healing ApplicationsPublication . Miguel, Sónia; Ribeiro, MP.; Coutinho, Paula Isabel Teixeira Gonçalves; Correia, Ilídio Joaquim SobreiraToday, 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.
- Biofunctionalization of electrospun poly(caprolactone) fibers with Maillard reaction products for wound dressing applicationsPublication . Simões, Déborah; Miguel, Sónia P.; Correia, I.J.Bacterial colonization of open skin wounds can interfere with the healing process, contributing to an increase in the severity of the wound. To overcome such drawback, wound dressings with an improved bactericidal activity have been developed or are currently under development. Herein, poly(caprolactone) (PCL) nanofibrous membranes functionalized with biosynthesized Maillard reaction products (MRPs) were produced using an electrospinning apparatus and their properties (chemical, morphological, mechanical and biological) analyzed in order to evaluate their suitability for being used as wound dressings. The functionalization of PCL nanofibers with MRPs allowed the production of membranes with the mechanical, wettability and porosity features required for wound exudate absorption as well as nutrients and gas exchange. Furthermore, MRPs-modified PCL membranes were also able to inhibit Staphylococcus aureus and Pseudomonas aeruginosa growth, without inducing any cytotoxic effect to human fibroblasts. These findings support the potential use of the produced membranes in the healing process.
- Photocrosslinkable Nanofibrous Asymmetric Membrane Designed for Wound DressingPublication . Alves, P.; Santos, Marta; Mendes, Sabrina; Miguel, Sónia; Sá, Kevin; Cabral, C.S.D.; Correia, I.J.; Ferreira, PaulaRecently, the biomedical scientists who are working in the skin regeneration area have proposed asymmetric membranes as ideal wound dressings, since they are able to reproduce both layers of skin and improve the healing process as well as make it less painful. Herein, an electrospinning technique was used to produce new asymmetric membranes. The protective layer was composed of a blending solution between polycaprolactone and polylactic acid, whereas the underlying layer was comprised of methacrylated gelatin and chitosan. The chemical/physical properties, the in vitro hemo- and biocompatibility of the nanofibrous membranes were evaluated. The results obtained reveal that the produced membranes exhibited a wettability able to provide a moist environment at wound site. Moreover, the membranes' hemocompatibility and fibroblast cell adhesion, spreading and proliferation at the surface of the membranes were also noticed in the in vitro assays. Such results highlight the suitability of these asymmetric membranes for wound dressing applications.