RESUMO
Type I collagen (Col_1) is one of the main proteins present in the skin extracellular matrix, serving as support for skin regeneration and maturation in its granulation stage. Electrospun materials have been intensively studied as the next generation of skin wound dressing mainly due to their high surface area and fibrous porosity. However, the electrospinning of collagen-based solutions causes degradation of its structure. In this work, a coaxial electrospinning process was proposed to overcome this limitation. The production of mats of polycaprolactone (PCL)-Col_1/PVA (collagen/poly(vinyl alcohol)) composed of core-shell nanofibers was investigated. PCL solution was used as the core solution, while Col_1/PVA was used as the shell solution. PVA was used to improve the processability of collagen, while PCL was employed to improve the mechanical properties and morphology of Col_1/PVA fibers. The morphology and the cytotoxicity of the fibers were highly dependent on the processing parameters. Defect-free core-shell nanofibers were obtained with a shell/core flow rates ratio = 4, flight distance of 12 cm, and an applied voltage of 16 kV. Using this strategy, the triple helix structure characteristic of the collagen molecule was preserved. Moreover, the common post-processing of solvent removal could be suppressed, simplifying the manufacturing processing of these biomaterials. The nanostructured mats showed no cytotoxicity, high liquid absorption, structural stability, hydrophilic character, and collagen release capacity, making them a potential novel dressing for skin damage regeneration, in special in the case of chronic wounds treatment, in which exogenous collagen delivery is necessary.
Assuntos
Colágeno Tipo I , Nanofibras , Nanofibras/química , Poliésteres/química , Cicatrização , Álcool de Polivinil/farmacologia , Álcool de Polivinil/química , Colágeno/farmacologiaRESUMO
The central nervous system shows limited regenerative capacity after injury. Spinal cord injury (SCI) is a devastating traumatic injury resulting in loss of sensory, motor, and autonomic function distal from the level of injury. An appropriate combination of biomaterials and bioactive substances is currently thought to be a promising approach to treat this condition. Systemic administration of valproic acid (VPA) has been previously shown to promote functional recovery in animal models of SCI. In this study, VPA was encapsulated in poly(lactic-co-glycolic acid) (PLGA) microfibers by the coaxial electrospinning technique. Fibers showed continuous and cylindrical morphology, randomly oriented fibers, and compatible morphological and mechanical characteristics for application in SCI. Drug-release analysis indicated a rapid release of VPA during the first day of the in vitro test. The coaxial fibers containing VPA supported adhesion, viability, and proliferation of PC12 cells. In addition, the VPA/PLGA microfibers induced the reduction of PC12 cell viability, as has already been described in the literature. The biomaterials were implanted in rats after SCI. The groups that received the implants did not show increased functional recovery or tissue regeneration compared to the control. These results indicated the cytocompatibility of the VPA/PLGA core-shell microfibers and that it may be a promising approach to treat SCI when combined with other strategies.
Assuntos
Animais , Masculino , Ratos , Traumatismos da Medula Espinal/terapia , Sistema Nervoso Central/efeitos dos fármacos , Ácido Valproico/administração & dosagem , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Teste de Materiais , Microscopia Eletrônica de Varredura , Ratos Wistar , Microfibrilas/química , Engenharia Tecidual/métodos , Modelos Animais de Doenças , Alicerces TeciduaisRESUMO
Electrospun (bio)polymeric fibers have attracted widespread interest as functional materials with suitable morphology and properties for their use as tissue engineering scaffolds and/or wound dressings. The fibrous/porous morphology of this type of materials promotes the adhesion and proliferation of tissue cells, but on the other hand, pathogenic microorganisms unfortunately can also be attached to the fibers, thus leading to serious infections and consequently to the immediate removal of the scaffolds or wound dressings, which may imply greater tissue damage. In this context, this review addresses the more recent approaches based on electrospinning and related techniques for developing composite (bio)polymeric fibers with tailored antimicrobial properties either by using mere electrospinning for the incorporation of well-defined antimicrobial nanoparticles (silver, gold, titanium dioxide, zinc oxide, copper oxide, etc.) or by resorting to the combination of electrospraying and electrospinning for the generation of nanoparticle-coated fibers, as well as coaxial electrospinning for obtaining fibers with nanoparticle-rich surface.
Assuntos
Anti-Infecciosos/farmacologia , Biopolímeros/farmacologia , Engenharia Tecidual/métodos , Humanos , Nanopartículas/química , Cicatrização/efeitos dos fármacosRESUMO
AIM: Scaffolds are a promising approach for spinal cord injury (SCI) treatment. FGF-2 is involved in tissue repair but is easily degradable and presents collateral effects in systemic administration. In order to address the stability issue and avoid the systemic effects, FGF-2 was encapsulated into core-shell microfibers by coaxial electrospinning and its in vitro and in vivo potential were studied. Materials & methods: The fibers were characterized by physicochemical and biological parameters. The scaffolds were implanted in a hemisection SCI rat model. Locomotor test was performed weekly for 6 weeks. After this time, histological analyses were performed and expression of nestin and GFAP was quantified by flow cytometry. Results: Electrospinning resulted in uniform microfibers with a core-shell structure, with a sustained liberation of FGF-2 from the fibers. The fibers supported PC12 cells adhesion and proliferation. Implanted scaffolds into SCI promoted locomotor recovery at 28 days after injury and reduced GFAP expression. CONCLUSION: These results indicate the potential of these microfibers in SCI tissue engineering. [Formula: see text].