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In the present study, we sought to develop materials applicable to personal and collective protection equipment to mitigate SARS-CoV-2. For this purpose, AgNPs were synthesized and stabilized into electrospinning nanofiber matrices (NMs) consisting of poly(vinyl alcohol) (PVA), chitosan (CHT), and poly-ε-caprolactone (PCL). Uniaxial nanofibers of PVA and PVA/CHT were developed, as well as coaxial nanofibers of PCL[PVA/CHT], in which the PCL works as a shell and the blend as a core. A crucial aspect of the present study is the in situ synthesis of AgNPs using PVA as a reducing and stabilizing agent. This process presents few steps, no additional toxic reducing agents, and avoids the postloading of drugs or the posttreatment of NM use. In general, the in situ synthesized AgNPs had an average size of 11.6 nm, and the incorporated nanofibers had a diameter in the range of 300 nm, with high uniformity and low polydispersity. The NM's spectroscopic, thermal, and mechanical properties were appropriate for the intended application. Uniaxial (PVA/AgNPs and PVA/CHT/AgNPs) and coaxial (PCL[PVA/CHT/AgNPs]) NMs presented virucidal activity (log's reduction ≥ 5) against mouse hepatitis virus (MHV-3) genus Betacoronavirus strains. In addition to that, the NMs did not present cytotoxicity against fibroblast cells (L929 ATCC® CCL-1TM lineage).
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Development of efficient catalysts for oxygen evolution reaction (OER) remains challenging in PEM dehumidifier or vapor electrolyzer. This study developed novel coaxial IrOx@SbSnOx nanofiber (NF) catalysts by electrospinning using a dual-channel needle. This method ensures the fibrous structure and the uniform loading of Ir oxide on the support of antimony tin oxide (ATO). IrO2@SbSnOx nanoparticles were synthesized for comparison. Characterizations showed that the active area and charge transfer resistance of NF was 1.47 times and 17.72% of that of commercial ones, respectively. The overpotential of NF at 10 mA·cm-2 was 359 mV, much smaller than that of commercial IrO2 (418 mV). In addition, the reaction overpotential of NF increased by only 38 mV after 1000 cyclic voltammetry cycles, indicating good electrochemical stability. To explore the enhancement mechanism, first-principles calculations were conducted for theoretically simulating the hetero-structures. Based on d-band theory, the structure formed between ATO and IrO2 can effectively weaken the adsorption of oxygen intermediates on the catalyst surface, which reduces the OER energy barrier from 1.705 to 1.632 eV, causing an over 15% decrease of overpotential after loading on ATO. As a practical attempt, we applied the new catalysts in real PEM assembly for air dehumidification and found that the performance was improved by about 2 times compared with that using commercial catalysts. This study provides a research direction for the design of one-dimensional NF catalysts and their using in PEM applications.
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BACKGROUND: Stent-graft-induced inflammation is an independent risk factor for adverse aortic remodeling in aortic dissection. In this context, we asked that whether a methylprednisolone-loaded stent-graft could reduce inflammation and degradation. METHODS: First, a coaxial electrospinning technique was used to create a core-shell film with methylprednisolone encapsulated in the inner of poly (L-lactide-co-caprolactone) nanofibers for controllable drug release. Second, an in vitro study was conducted to evaluate the biocompatibility of the nanofiber meshes. Third, the porcine aortic dissection model was developed to investigate the therapeutic effects of the methylprednisolone-loaded stent-graft. RESULTS: The results demonstrated that the nanofiber-coated film with a methylprednisolone-poly-caprolactone core layer and a poly (L-lactide-co-caprolactone) shell layer could effectively sustain drug release in vitro. In vivo study showed that the methylprednisolone-loaded stent-graft could reduce degradtion of aortic dissection by regulating inflammation. CONCLUSIONS: Overall, the controllable drug release by coaxial nanofiber is a promising approach to alleviate aortic inflammation and promote aortic remodeling after stent-graft implantation.
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Combining multiple drugs or biologically active substances for wound healing could not only resist the formation of multidrug resistant pathogens, but also achieve better therapeutic effects. Herein, the hydrophobic fluoroquinolone antibiotic ciprofloxacin (CIP) and the hydrophilic broad-spectrum antibiotic tetracycline hydrochloride (TH) were introduced into the coaxial polycaprolactone/gelatin (PCL/GEL) nanofiber mat with CIP loaded into the PCL (core layer) and TH loaded into the GEL (shell layer), developing antibacterial wound dressing with the co-delivering of the two antibiotics (PCL-CIP/GEL-TH). The nanostructure, physical properties, drug release, antibacterial property, and in vitro cytotoxicity were investigated accordingly. The results revealed that the CIP shows a long-lasting release of five days, reaching the releasing rate of 80.71%, while the cumulative drug release of TH reached 83.51% with a rapid release behavior of 12 h. The in vitro antibacterial activity demonstrated that the coaxial nanofiber mesh possesses strong antibacterial activity against E. coli and S. aureus. In addition, the coaxial mats showed superior biocompatibility toward human skin fibroblast cells (hSFCs). This study indicates that the developed PCL-CIP/GEL-TH nanofiber membranes hold enormous potential as wound dressing materials.
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Ciprofloxacina/administración & dosificación , Escherichia coli/crecimiento & desarrollo , Piel/citología , Staphylococcus aureus/crecimiento & desarrollo , Tetraciclina/administración & dosificación , Cicatrización de Heridas , Animales , Vendajes , Línea Celular , Ciprofloxacina/química , Ciprofloxacina/farmacología , Modelos Animales de Enfermedad , Composición de Medicamentos , Sinergismo Farmacológico , Escherichia coli/efectos de los fármacos , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Gelatina/química , Humanos , Viabilidad Microbiana , Nanofibras , Poliésteres/química , Piel/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Tetraciclina/química , Tetraciclina/farmacologíaRESUMEN
We demonstrate a simple, effective and feasible method to address the shrinkage of Poly (lactic-co-glycolic acid) (PLGA) through a core-shell structure fiber strategy. The results revealed that introducing size-stable poly-caprolactone (PCL) as the core fiber significantly improved the PLGA-based fibrous scaffold's dimensional maintenance. We further utilized fish collagen to modify the PLGA shell layer (PFC) of coaxial fibers and loaded baicalin (BA) into the PCL core layer (PCL-BA) to endow fibrous scaffold with more functional biological cues. The PFC/PCL-BA fibrous scaffold promoted the osteogenic differentiation of bone mesenchymal stem cells and stimulated the RAW264.7 cells to polarize into a pro-reparative phenotype. Importantly, the in vivo study demonstrated that the PFC/PCL-BA scaffold could regulate inflammation and osteoclast differentiation, favor neovascularization and bone formation. This work tactfully combined PLGA and PCL to establish a drug release platform based on the core-shell fibrous scaffold for vascularized bone regeneration.
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In the present study, a coaxial nanofiber membrane was developed using the electrospinning technique. The developed membranes were fabricated from hydrophilic cellulose acetate (CA) polymer and hydrophobic polysulfone (PSf) polymer as a core and shell in an alternative way with addition of 0.1 wt.% of ZnO nanoparticles (NPs). The membranes were treated with a 2M NaOH solution to enhance hydrophilicity and thus increase water separation flux. Chemical and physical characterizations were performed, such as Fourier transform infrared (FTIR) spectroscopy, and surface wettability was measured by means of water contact angle (WCA), mechanical properties, surface morphology via field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and microscopy energy dispersive (EDS) mapping and point analysis. The results show higher mechanical properties for the coaxial nanofiber membranes which reached a tensile strength of 7.58 MPa, a Young's modulus of 0.2 MPa, and 23.4 M J.m-3 of toughness. However, treated mebranes show lower mechanical properties (tensile strength of 0.25 MPa, Young's modulus of 0.01 MPa, and 0.4 M J.m-3 of toughness). In addition, the core and shell nanofiber membranes showed a uniform distribution of coaxial nanofibers. Membranes with ZnO NPs showed a porous structure and elimination of nanofibers after treatment due to the formation of nanosheets. Interestingly, membranes changed from hydrophobic to hydrophilic (the WCA changed from 90 ± 8° to 14 ± 2°). Besides that, composite nanofiber membranes with ZnO NPs showed antibacterial activity against Escherichia coli. Furthermore, the water flux for the modified membranes was improved by 1.6 times compared to the untreated membranes.
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Aim: To develop an effective strategy for increasing angiogenesis at diabetic wound sites and thereby accelerating wound healing. Materials & methods: A micropatterned nanofibrous scaffold with bioglass nanoparticles encapsulated inside coaxial fibers was prepared by electrospinning. Results: Si ions could be released in a sustained manner from the scaffolds. The hierarchical micro-/nano-structure of the scaffold was found to act as a temporary extracellular matrix to promote endothelial cell adhesion and growth. The scaffold greatly improved angiogenesis and collagen deposition at the wound site, which shortened the healing period of diabetic wounds. Conclusion: This study provides a promising therapeutic option for chronic diabetic wounds with improved angiogenesis.
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Diabetes Mellitus , Nanofibras , Cerámica , Preparaciones de Acción Retardada , Matriz Extracelular , Humanos , Andamios del Tejido , Cicatrización de HeridasRESUMEN
Vascular implants remain clinically challenged due to often-occurring thrombosis and stenosis. Critical to addressing these complications is the design of implant material surfaces to inhibit the activities of platelets, smooth muscle cells (SMCs) and inflammatory cells. Recent mechanobiology studies accentuate the significance of material elasticity to cells and tissues. We thus developed and characterized an implant coating composed of hybrid, viscoelastic microfibers with coaxial core-sheath nanostructure. The coating over metallic stent material was formed by first depositing coaxially-electrospun fibers of poly(L-lactic acid) core and polyethylene glycol dimethacrylate sheath, and then polymerizing fibers with various UV times. Material characterizations were performed to evaluate the coating structure, mechanical property and biocompatibility. Results showed that coaxial microfibers exhibited arterial-like mechanics. The soft surface, high water content and swelling ratio of the coaxial fibers resemble hydrogels, while they are mechanically strong with an elastic modulus of 172-729â¯kPa. The coating strength and surface elasticity were tunable with the photopolymerization time. Further, the elastic fibers, as conformal coating on stent metal, strongly reduced SMC overgrowth and discouraged platelet adhesion and activation, compared to bare metals. Importantly, after 7-day subcutaneous implantation, coaxial fiber-coated implants showed more favorable in vivo responses with reduced tissue encapsulation, compared to bare stent metals or those coated with a two-layered fiber mixture composed of fibers from individual polymers. The excellent biocompatibility aroused from nanostructural interfaces of hybrid fibers offering hydrated, soft, nonfouling microenvironments. Such integrated fiber system may allow creation of advanced vascular implants that possess physico-mechanical properties of native arteries.
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Prótesis Vascular , Materiales Biocompatibles Revestidos/química , Hidrogeles/química , Metacrilatos/química , Nanofibras/química , Poliésteres/química , Polietilenglicoles/química , Animales , Plaquetas/citología , Plaquetas/efectos de los fármacos , Bovinos , Supervivencia Celular/efectos de los fármacos , Materiales Biocompatibles Revestidos/farmacología , Materiales Biocompatibles Revestidos/efectos de la radiación , Elasticidad , Técnicas Electroquímicas , Hidrogeles/farmacología , Hidrogeles/efectos de la radiación , Miocitos del Músculo Liso/citología , Miocitos del Músculo Liso/efectos de los fármacos , Nanofibras/efectos de la radiación , Nanofibras/ultraestructura , Adhesividad Plaquetaria/efectos de los fármacos , Polimerizacion , Cultivo Primario de Células , Ratas , Propiedades de Superficie , Rayos Ultravioleta , ViscosidadRESUMEN
In this study, we fabricated a doxycycline (doxy)-eluting nanofiber-covered endotracheal stent for the prevention of stent intubation-related tissue fibrosis and re-stenosis. The nanofiber was deposited directly on the outer surface of the stent using a coaxial electrospinning method to form a doxy-eluting cover sleeve. Poly(d,l-lactide) was used as the shell-forming polymer and dedicated drug release-control membrane. Polyurethane was selected as the drug-loading core polymer. The compositional ratio of the core to shell was adjusted to 1:0, 1:2, and 1:4 by changing the electro-spray rate of each polymeric solution and microscopic observation of nanofibers using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and the fluorescence microscopy proved core-shell structure of nanofibers. The in vitro release study suggested that the release of doxy could be controlled by increasing the compositional ratio of the shell. The growth of HT1080 fibrosarcoma cells was inhibited by the 10% doxy-containing nanofiber. The real-time polymerase chain reaction (PCR) in HT1080 cells and xenografted tissue models indicated that the doxy-releasing nanofiber inhibited mRNA expression of metalloproteinases (MT1-MMP, MMP-2, and MMP-9). Overall, our study demonstrates that a doxy-eluting core-shell nanofiber stent can be successfully fabricated using coaxial electrospinning and displays the potential to prevent fibrotic re-stenosis, which is the most problematic clinical complication of tracheal stent intubation.
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Sodium alginate and chitosan were in favor of wound healing. However, the two polymers were not compatible in one formulation due to the electrostatic interaction. Coaxially electrospinning technology could make two or more noneletrospun polymers to be electrospun in independent core and shell layer. Asiaticoside-loaded coaxially electrospinning nanofibers of alginate, polyvinyl alcohol (PVA) and chitosan (alginate/PVA/chitosan) were prepared and evaluated. Morphologies and microstructure of nanofibers were observed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Drug release in vitro of coaxial nanofibers was also evaluated. Deep partial-thickness burn injury were established and used to evaluate the improved healing effect of asiaticoside-loaded coaxial nanofibers. Drug-loaded coaxial nanofibers prepared with the optimized formulations and technologies had the obvious core-shell structure. Coaxial nanofibers showed faster drug release profiles in vitro and this facilitated wound healing. Its healing effect on rats with deep partial-thickness burn injury was also significant based on morphology, wound healing ratio, and pathological sections. Positive expression of vascular endothelial growth factor (VEGF), cluster of differentiation 31 (CD31), and proliferating cell nuclear antigen (PCNA), and down regulation of tumor necrosis factor (TNF) and interleukin-6 (IL-6) also validated the improved effect of wound healing. In general, the asiaticoside-loaded coaxial nanofibers had obvious core-shell structure with smooth surface and uniform diameter. Its healing effect on deep partial-thickness burn injury of rats was obvious. Asiaticoside-loaded coaxial nanofibers provide a novel promising option for treatment of deep partial-thickness burn injury.