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This study investigates the fabrication of chitosan (CS)/polyvinyl alcohol (PVA) blend nanofibers via electrospinning, aiming to create nanofibers with enhanced properties for broad applications. The research focuses on optimizing electrospinning parameters to reduce bead formation and achieve uniform nanofiber morphology. A detailed experimental design, employing a nineteen-point plan developed with Design-Expert software, examined variables such as polymer concentration, distance from the needle to the collector, the required voltage, and the rate at which solution was ejected from the needle. Morphological characteristics of the nanofibers were analyzed using advanced microscopy, complemented by drug release and wound healing assessments. The optimal electrospinning conditions were determined to be a 1:3 CS/PVA solution concentration ratio, an 8 cm needle-to-collector distance, a 20 kV applied voltage, and a 1 mL/hour flow rate. Scanning electron microscopy revealed uniform nanofibers with diameters between 100 to 250 nm, devoid of bead defects. In-vitro analysis demonstrated a sustained release profile of azilsartan (AZL), while in-vivo studies on rats indicated enhanced wound healing, corroborated by histological examination. The findings suggest that CS/PVA nanofibers, fabricated under these conditions, possess promising characteristics for use as a drug-delivery scaffold in wound treatment applications.
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BACKGROUND:Currently,electrospun nanofibers,which are biomimetic materials of natural extracellular matrix and contain a three-dimensional network of interconnected pores,have been successfully used as scaffolds for various tissue regeneration,but are still faced with the challenge of extending the biomaterials into three-dimensional structures to reproduce the physiological,chemical as well as mechanical properties of the tissue microenvironment. OBJECTIVE:To summarize the process and principles of electrostatic spinning and to explore the applications of the resulting electrospun nanofibers in tissue regeneration of skin,blood vessels,nerves,bone,cartilage and tendons/ligaments. METHODS:With"electrospinning,electrospun nanofibers,electrospun nanofiber scaffolds,tissue regeneration"as the Chinese and English search terms,Google Academic Database,PubMed,and CNKI were searched,and finally 88 articles were included for review. RESULTS AND CONCLUSION:(1)The electrospun nanofibers are a natural fibrous extracellular matrix mimetic material and contain a three-dimensional network of interconnected pores that have been successfully used as scaffolds for a variety of tissue regeneration applications.(2)Several papers have described the great potential of electrospun nanofiber scaffolds applied to the regeneration of skin,blood vessels,nerves,bones,cartilage and tendons/ligaments,providing a solid theoretical basis for its final application in clinical disease treatment,or for its transformation into practical products to enter the market.(3)However,the current research results are mostly based on cell experimental research results in vitro,and whether it can be finally applied to human body still needs clinical verification.(4)At present,many kinds of electrospun products for various clinical needs have been commercialized in and outside China,indicating that the research field of electrospun nanofiber scaffolds for soft and hard tissue regeneration has great research value and application potential.
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BACKGROUND:The combination of good biomechanical properties,controlled drug release and multi-functionality of core-shell structured nanofibers is receiving more and more attention,which also makes them promising for a wide range of applications in the field of oral tissue regeneration. OBJECTIVE:To summarize the preparation,drug loading and release mechanisms of core-shell structured nanofibers and their application in the regenerative repair of oral tissues. METHODS:A computer search of the literature collected in CNKI and PubMed from January 2000 to November 2022 was applied,and the search terms in English and Chinese were"electrospinning,core-shell structures,drug delivery systems,jaw bone regeneration,cartilage regeneration,periodontal tissue regeneration". RESULTS AND CONCLUSION:(1)There are various methods for the preparation of core-shell structured nanofibers,but the coaxial and emulsion methods of electrostatic spinning have unique advantages such as simple operation,diverse material selection and good biocompatibility.(2)Core-shell structured nanofibers can be used as bacteriostatic agents,carriers of different types of drugs,and scaffolds for cell adhesion,providing new therapeutic options for oral tissue regeneration.(3)Controlled degradation and drug release rate of core-shell structured nanofibers can better adapt to the healing process of oral tissue defect repair and achieve ideal tissue regeneration.
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BACKGROUND:Due to the sudden release and the rapid removal by proteases,platelet-rich plasma hydrogel leads to shorter residence times of growth factors at the wound site.In recent years,researchers have focused on the use of hydrogels to encapsulate platelet-rich plasma in order to improve the deficiency of platelet-rich plasma hydrogels. OBJECTIVE:To prepare self-assembled polypeptide-platelet-rich plasma hydrogel and to explore its effects on the release of bioactive factors of platelet-rich plasma. METHODS:The self-assembled polypeptide was synthesized by the solid-phase synthesis method,and the solution was prepared by D-PBS.Hydrogels were prepared by mixing different volumes of polypeptide solutions with platelet-rich plasma and calcium chloride/thrombin solutions,so that the final mass fraction of polypeptides in the system was 0.1%,0.3%,and 0.5%,respectively.The hydrogel state was observed,and the release of growth factors in platelet-rich plasma was detected in vitro.The polypeptide self-assembly was stimulated by mixing 1%polypeptide solution with 1%human serum albumin solution,so that the final mass fraction of the polypeptide was 0.1%,0.3%,and 0.5%,respectively.The flow state of the liquid was observed,and the rheological mechanical properties of the self-assembled polypeptide were tested.The microstructure of polypeptide(mass fraction of 0.1%and 0.001%)-human serum albumin solution was observed by scanning electron microscope and transmission electron microscope. RESULTS AND CONCLUSION:(1)Hydrogels could be formed between different volumes of polypeptide solution and platelet-rich plasma.Compared with platelet-rich plasma hydrogels,0.1%and 0.3%polypeptide-platelet-rich plasma hydrogels could alleviate the sudden release of epidermal growth factor and vascular endothelial growth factor,and extend the release time to 48 hours.(2)After the addition of human serum albumin,the 0.1%polypeptide group still exhibited a flowing liquid,the 0.3%polypeptide group was semi-liquid,and the 0.5%polypeptide group stimulated self-assembly to form hydrogel.It was determined that human serum albumin in platelet-rich plasma could stimulate the self-assembly of polypeptides.With the increase of the mass fraction of the polypeptide,the higher the storage modulus of the self-assembled polypeptide,the easier it was to form glue.(3)Transmission electron microscopy exhibited that the polypeptide nanofibers were short and disordered before the addition of human serum albumin.After the addition of human serum albumin,the polypeptide nanofibers became significantly longer and cross-linked into bundles,forming a dense fiber network structure.Under a scanning electron microscope,the polypeptides displayed a disordered lamellar structure before adding human serum albumin.After the addition of human serum albumin,the polypeptides self-assembled into cross-linked and densely arranged porous structures.(4)In conclusion,the novel polypeptide can self-assemble triggered by platelet-rich plasma and the self-assembly effect can be accurately adjusted according to the ratio of human serum albumin to polypeptide.This polypeptide has a sustained release effect on the growth factors of platelet-rich plasma,which can be used as a new biomaterial for tissue repair.
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BACKGROUND:In recent years,there have been many novel tympanic membrane repair materials,including patches and 3D-printed scaffolds.However,the tympanic membrane repaired by these materials is different from the natural tympanic membrane in terms of thickness and internal structure. OBJECTIVE:To explore the efficacy of bone marrow mesenchymal stem cells-loaded high-porosity polycaprolactone/collagen nanofiber membrane scaffolds in repairing chronic tympanic membrane perforation. METHODS:Polycaprolactone,polycaprolactone-collagen,and high-porosity polycaprolactone-collagen nanofiber membranes were prepared by electrospinning technology,and the surface morphology,porosity and cell compatibility of the scaffolds were characterized.The tympanic membrane perforation model of 50 male SD rats was established by puncturing the posterior lower part of both eardrums with a sterile 23-measure needle combined with mitomycin C and hydrocortisone.After 12 weeks of modeling,the rats were divided into five groups by the random number table method.The blank control group did not receive any treatment.In the other four groups,polycaprolactone nanofiber membrane(polycaprolactone group),polycaprolactone-collagen nanofiber membrane(polycaprolactone-collagen group),high-porosity polycaprolactone-collagen nanofiber membrane(high-porosity polycaprolactone-collagen group)and high-porosity polycaprolactone-collagen nanofiber membrane containing bone marrow mesenchymal stem cells(high-porosity polycaprolactone-collagen group)were implanted at the perforation of the tympanic membrane,respectively.Each group consisted of 10 animals.The healing of the tympanic membrane was examined by otoendoscopy after 1,2,3 and 4 weeks of stent implantation.Hematoxylin-eosin staining,Masson staining,and Ki-67 immunohistochemical staining were performed on the tympanic membrane after 4 weeks of implantation. RESULTS AND CONCLUSION:(1)Scaffold characterization:Scanning electron microscopy showed that compared with other nanofiber membranes,the high-porosity polycaprolactone-collagen nanofiber membranes had more orderly nanofiber structure,larger surface pore size,and higher porosity(P<0.001).Live/dead staining showed that bone marrow mesenchymal stem cells adhered well on the three scaffolds,and the number of living cells on the high-porosity polycaprolactone-collagen nanofiber membrane was more than that on the other two scaffolds.Almarin staining showed that the proliferation rate of bone marrow mesenchymal stem cells on the high-porosity polycaprolactone-collagen nanofiber membrane was higher than that of the other two fiber membranes.(2)Animal experiments:Except for the blank control group,the tympanic membrane of the other four groups healed gradually with the extension of the time of fibrous membrane implantation,among which the healing speed of the cell-loaded high-porosity polycaprolactone-collagen group was the fastest.Hematoxylin-eosin staining,Masson staining,and Ki-67 immunohistochemical staining showed that the tympanic membrane of rats in the cell-carrying high-porosity polycaprolactone-collagen group was moderate in thickness and a three-layer structure with uniform collagen fiber layers,similar to the normal tympanic membrane,and the repair quality of tympanic membrane was better than that of other fiber membrane groups.(3)The results showed that the high-porosity polycaprolactone-collagen nanofiber membrane containing bone marrow mesenchymal stem cells could not only rapidly repair the perforation of the tympanic membrane,but also the newly healed tympanic membrane was similar to normal tympanic membrane in structure and thickness.
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BACKGROUND:Electrospun porous nanofiber exhibits excellent properties and designability.It is an effective way to control the release of traditional Chinese medicine and improve the bioavailability to design an advanced drug delivery system,which has a broad application prospect. OBJECTIVE:To review the construction methods of the electrospinning drug delivery system of traditional Chinese medicine and its related research progress in the medical field. METHODS:The literature search was performed in CNKI,PubMed,and Web of Science databases with the search terms"electrospinning,traditional Chinese medicine,drug carrier,drug delivery system,tissue engineering,dressing"in both English and Chinese for articles published from 2013 to 2023.Finally,62 articles were included in this review. RESULTS AND CONCLUSION:(1)The key elements of the electrospinning drug delivery system of Chinese medicine preparation are substrate material,traditional Chinese medicine composition,and drug loading method.(2)The preparation of the electrospinning drug delivery system of Chinese medicine can be carried out according to the application scenario and therapeutic purpose.Firstly,the types of Chinese medicine are selected,then the polymer matrix and solution suitable for them are selected,and finally,the fiber structure is designed according to the drug release requirements and the appropriate drug loading method is adopted.(3)At present,the medicinal agents used are mainly plant Chinese medicine,and there is a lack of systematic research on animal and mineral Chinese medicine.(4)Blended drug loading is the most studied and applied drug loading method,and its drug release characteristics and adaptation scenarios are constantly expanded by optimizing the physicochemical properties of the solution and selecting the diversity of loaded substances.Multilayer fibers with different compositions and properties can be prepared by coaxial,multi-axis,and sequential electrospinning methods,which have broad development prospects.(5)The early application of the electrospinning drug delivery system of Chinese medicine focused on medical dressings according to the antibacterial and hemostatic functions.In recent years,it has been studied in the field of tissue engineering because some components of traditional Chinese medicine can promote cell adhesion,proliferation,and differentiation.(6)At present,the research mainly focuses on the characterization and optimization of loading materials,processes,physicochemical properties,and biological properties,but the research on the mechanism is less.Its clinical application has not been widespread;the adverse reactions in vivo and the interaction between its degradation behavior and drug release behavior are still unknown.(7)Future studies need to consider:We should expand the application of Chinese medicine by improving the physicochemical properties and increasing the purification of Chinese medicine extracts.We need to comprehensively study the therapeutic effects and application mechanisms of Chinese medicine,and clarify the interaction of degradation behavior and drug release behavior,to achieve a more perfect combination and application of Chinese medicine and electrospinning nanofibers under a more accurate mechanism.
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Background: The nanofiber scaffolds achieved by the electrospinning technique have been used to develop several biological tissues, the nanofibers obtained by electrospinning procure a favorable microenvironment to mimic the extracellular matrix. Methods: Study type was of experimental. Study conducted at National Autonomous University of Mexico, from May 2018- May 2022. The protocol was approved by the research and ethics commissions of the UNAM school of medicine. A viscoelastic solution of polylactic-co-glycolic acid (PLGA) and polycaprolactone (PCL) in a 70:30 ratio and gelatin (Gel) in an 80:20 ratio was prepared while a dynamic collector was used with the electrospinning technique. Results: Mechanical and biological tests were carried out on the scaffold obtained by electrospinning; the resultant scaffold achieves good mechanical matching and structural similarity between the graft and the extrahepatic bile duct. Conclusions: In this study we managed to create a porous, biocompatible scaffold with good cell adhesion and proliferation, potentially applicable to tissue engineering, especially for the replacement of tubular organs such as blood vessels, bile ducts, and urethra.
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Nanomaterials, with the advantages of unique microstructure, have been widely used in the fields of material manufacturing, microelectronics and computer technology, medicine and health, environment and energy. Compared with traditional hemostatic materials, nanomaterials can improve the bioavailability and stability of traditional hemostatic drugs to a certain extent, enhance the controlled and targeted release of drugs, which lay a good foundation for the development of new-style modern hemostatic nanomaterials. This paper reviews the advanced design and application progress of various nanomaterials in hemostasis, such as liposomes, nanoparticles, self-assembled nano peptides, nanofibers, etc. Finally, the challenges and prospects of hemostatic nanomaterials are briefly described.
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In this study, the fibers of invasive species
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La producción de nanofibra en scaffolds utilizando la tecnología de electrospinning abarca muchos parámetros tanto físicos como químicos que han sido estudiados y que todavía no se han dilucidado completamente. Tanto la utilización de polímeros naturales, que por sus características tienen una mayor afinidad y una mayor biocompatibilidad con los procesos celulares, así mismo, una biomimetizacion similar a la estructura de la matriz celular natural del cuerpo; sin embargo, la falta de control sobre algunas sus características físicas repercuten directamente en características biológicas de la célula. Por otro lado, la utilización de polímeros sintéticos nos permite controlar características físicas, pero esto afecta el desarrollo de las células. Por ello, este artículo presenta una breve revisión de artículos científicos acerca del electrospinning y los biomateriales más utilizados para la obtención de scaffolds en el campo de la biomedicina.
Nanofiber production in scaffolds using electrospinning technology encompasses many physical and chemical parameters that have been studied and have not yet been fully elucidated. Both the use of natural polymers, which due to their characteristics have a higher affinity and a greater biocompatibility with cellular processes, as well as a biomimetization similar to the structure of the body's natural cellular matrix; however, the lack of control over some of its physical characteristics directly affects the biological characteristics of the cell. On the other hand, the use of synthetic polymers allows us to control physical characteristics, but this affects the development of cells. For this reason, this article presents a brief review of scientific articles about Electrospinning and the most used materials for obtaining scaffolds in the field of biomedicine.
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The utilization of electrospinning in drug delivery has thrived in recent years, with the ability to incorporate drugsand enhance dissolution; this technique is employed to improve the dissolution of poorly water-soluble selectivephosphodiesterase-5 inhibitor, tadalafil. The strategy involved direct electrospinning of tadalafil/polyvinylpyrrolidoneand polyethylene oxide (PEO) solution. The optimization process included a 32 full factorial design based on theinfluence of polymers concentration as independent variables on the electrospun yield, loading efficiency, nanofibersdiameter, number of beads, and in vitro release. Optimization studies revealed the negative influence of bothpolymers on the electrospun yield, while the loading efficiency and in vitro dissolution rate were reduced by the PEOconcentration solely. The higher polymer concentrations were favorable for the declination of beads number, and adriving factor for fiber diameter reduction. Further physicochemical characterization of the optimized formulationrevealed the presence of the drug in an amorphous state or molecular dispersion within the polymer matrix. In vitrodissolution studies revealed about 81.5% ± 8.34% release in less than 2 minutes compared to a negligible dissolutionof free drug. From the derived outcomes, the electrohydrodynamic spun tadalafil-loaded nanofibers pave the way fordissolution enhancement for insoluble low bioavailability class II drugs.
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The radiotherapy modulators used in clinic have disadvantages of high toxicity and low selectivity. For the first time, we used the
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Nanofibers can mimic natural tissue structure by creating a more suitable environment for cells to grow, prompting a wide application of nanofiber materials. In this review, we include relevant studies and characterize the effect of nanofibers on mesenchymal stem cells, as well as factors that affect cell adhesion and osteogenic differentiation. We hypothesize that the process of bone regeneration in vitro is similar to bone formation and healing in vivo, and the closer nanofibers or nanofibrous scaffolds are to natural bone tissue, the better the bone regeneration process will be. In general, cells cultured on nanofibers have a similar gene expression pattern and osteogenic behavior as cells induced by osteogenic supplements in vitro. Genes involved in cell adhesion (focal adhesion kinase (FAK)), cytoskeletal organization, and osteogenic pathways (transforming growth factor-β (TGF-β)/bone morphogenic protein (BMP), mitogen-activated protein kinase (MAPK), and Wnt) are upregulated successively. Cell adhesion and osteogenesis may be influenced by several factors. Nanofibers possess certain physical properties including favorable hydrophilicity, porosity, and swelling properties that promote cell adhesion and growth. Moreover, nanofiber stiffness plays a vital role in cell fate, as cell recruitment for osteogenesis tends to be better on stiffer scaffolds, with associated signaling pathways of integrin and Yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ). Also, hierarchically aligned nanofibers, as well as their combination with functional additives (growth factors, HA particles, etc.), contribute to osteogenesis and bone regeneration. In summary, previous studies have indicated that upon sensing the stiffness of the nanofibrous environment as well as its other characteristics, stem cells change their shape and tension accordingly, regulating downstream pathways followed by adhesion to nanofibers to contribute to osteogenesis. However, additional experiments are needed to identify major signaling pathways in the bone regeneration process, and also to fully investigate its supportive role in fabricating or designing the optimum tissue-mimicking nanofibrous scaffolds.
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BACKGROUND: The application of tissue engineering in the repair of spinal cord injury is a focus of research in recent years, and most of the studies are still in vitro stage. OBJECTIVE: To explore the effect of repairing spinal cord injury with tissue-engineered spinal cord that was composed of new collagen nanofiber membrane and neural stem cells. METHODS: Collagen was used as raw material, and the nanofiber membrane with parallel arrangement and staggered arrangement of fibers was prepared by electronic spinning technology. The spinal cord derived neural stem cells of neonate rats were cultured on two kinds of nanofibers for 7 days to construct the tissue-engineered spinal cord. Sprague-Dawley rat models of spinal cord hemisection were randomly divided into five groups. In the blank control group, any material was not used. In the parallel tissue engineering group and cross tissue engineering group, corresponding tissue-engineered spinal cord was used. In the parallel group and cross group, corresponding nanofiber membrane was used. At 1-8 weeks after the operation, modified BBB scores of the rats were recorded. At 8 weeks after operation, the spinal cord was taken and stained with hematoxylin and eosin and received immunohistochemistry. The experiments were approved by experimental animal welfare and Ethics Management Committee of Harbin Medical University. RESULTS AND CONCLUSION: (1) The BBB scores in the parallel tissue engineering group were higher than those in the other four groups (P < 0.05). The BBB scores in the staggered tissue engineering group, the parallel group and the staggered group were all higher than those in the blank control group (P < 0.05). The BBB scores in the staggered tissue engineering group were higher than those in the parallel group and the staggered group at 2-8 weeks after operation (P < 0.05). The BBB scores in the parallel group were higher than those in the staggered group at 1 and 2 weeks after operation (P < 0.05). (2) Hematoxylin-eosin staining showed that there was almost no cell structure in the injury area of the blank control, and a large number of scar tissue formation was seen. The formation of scar tissue was inhibited in the parallel group and the staggered group, and the tissue repair was not obvious; the scar formation in the adjacent tissue and no cell connection was established between the injury area and the surrounding area. There were a large number of cell components in the scaffold degradation area of the two tissue engineering groups, and there were obvious tissue regeneration, more cells distributed along the direction of the scaffold; connections were built among the cells and with normal tissues. (3) Immunohistochemistry staining showed that neurons were seen in the two tissue engineering groups. (4) The results showed that the effect of nano tissue engineering on the repair of spinal cord injury was good, and the effect of parallel nano fiber membrane was better.
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Nanofibers can mimic natural tissue structure by creating a more suitable environment for cells to grow, prompting a wide application of nanofiber materials. In this review, we include relevant studies and characterize the effect of nanofibers on mesenchymal stem cells, as well as factors that affect cell adhesion and osteogenic differentiation. We hypothesize that the process of bone regeneration in vitro is similar to bone formation and healing in vivo, and the closer nanofibers or nanofibrous scaffolds are to natural bone tissue, the better the bone regeneration process will be. In general, cells cultured on nanofibers have a similar gene expression pattern and osteogenic behavior as cells induced by osteogenic supplements in vitro. Genes involved in cell adhesion (focal adhesion kinase (FAK)), cytoskeletal organization, and osteogenic pathways (transforming growth factor-β (TGF-β)/bone morphogenic protein (BMP), mitogen-activated protein kinase (MAPK), and Wnt) are upregulated successively. Cell adhesion and osteogenesis may be influenced by several factors. Nanofibers possess certain physical properties including favorable hydrophilicity, porosity, and swelling properties that promote cell adhesion and growth. Moreover, nanofiber stiffness plays a vital role in cell fate, as cell recruitment for osteogenesis tends to be better on stiffer scaffolds, with associated signaling pathways of integrin and Yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ). Also, hierarchically aligned nanofibers, as well as their combination with functional additives (growth factors, HA particles, etc.), contribute to osteogenesis and bone regeneration. In summary, previous studies have indicated that upon sensing the stiffness of the nanofibrous environment as well as its other characteristics, stem cells change their shape and tension accordingly, regulating downstream pathways followed by adhesion to nanofibers to contribute to osteogenesis. However, additional experiments are needed to identify major signaling pathways in the bone regeneration process, and also to fully investigate its supportive role in fabricating or designing the optimum tissue-mimicking nanofibrous scaffolds.
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Electrospinning technology opens up a new method for the construction of drug delivery system. The unique fiber structures of drug-loaded electrospinning nanofibers with the characteristics of similar to the extracellular matrix,good air permeability and hygroscopicity are very suitable for transdermal drug delivery systems.In this paper, the definition, characteristics, matrix selection, preparation methods, drug-loaded forms and drug-released profiles of drug-loaded electrospinning nanofibers are summarized and analyzed. Meanwhile, the application of drug-loaded electrospinning nanofbiers in the transdermal drug delivery systems is analyzed. This review is to provide support for the further studies on electrospun nanofiber transdermal drug delivery system.
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The concept of cellular reprogramming was developed to generate induced neural precursor cells (iNPCs)/dopaminergic (iDA) neurons using diverse approaches. Here, we investigated the effects of various nanoscale scaffolds (fiber, dot, and line) on iNPC/iDA differentiation by direct reprogramming. The generation and maturation of iDA neurons (microtubule-associated protein 2-positive and tyrosine hydroxylase-positive) and iNPCs (NESTIN-positive and SOX2-positive) increased on fiber and dot scaffolds as compared to that of the flat (control) scaffold. This study demonstrates that nanotopographical environments are suitable for direct differentiation methods and may improve the differentiation efficiency.
Тема - темы
Cellular Reprogramming , Nanofibers , Neurons , TyrosineРеферат
Purpose: The purpose of the study was to evaluate tissue reaction to polycaprolactone (PCL) nanofiber patches in the cornea, conjunctiva, and anterior chamber (AC) in rabbit eyes and to assess their biocompatibility for use as patch grafts. Methods: Two 100 ? PCL patches were implanted under the conjunctiva and in the corneal stroma of one albino New Zealand rabbit, and pathologic evaluation was done after 3 weeks. In the next step, two PCL patches were implanted; one in the corneal stroma and the other in the AC of two rabbits followed by pathologic evaluation after 3 months. Results: On slit-lamp examination, there was minimum inflammation in all cases. Pathologic examination showed that the contact and probably merging between the host tissue and PCL fibers were achieved with minimal tissue reaction. Conclusion: As a biocompatible material, PCL nanofibers seem to be a promising modality for the repair of different tissue defects including melting, thinning, and perforation. They may also be a suitable material for manufacturing keratoprostheses.
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A new method was proposed for analysis of the organic compounds in cigarette smoke by high resolution Orbitrap mass spectrometry based on polyacrylonitrile-silica (PAN-SiO2) nanofiber membrane extraction and methanol elution.Hydrophobic PAN-SiO2 nanofiber membrane which was used to enrich small molecular organic compounds in cigarette smoke was prepared by the technology of electrospinning.Several parameters including the concentrations of PAN and SiO2 nanopartical,elecrospining voltage,needle aperture and flow rate of spinning solution were optimized.Under the optimal conditions,a PAN-SiO2 nanofiber membrane with good adsorption performance and great physical strength was obtained.A total of 21 compounds including acetone,styrene,acrolein,isoprene,and acrylonitrile were identified by analyzing the cigarette smoke with Orbitrap MS spectrometry in the positive ion mode.Six organic acids including salicylic acid,malic acid and lactic acid were detected in negative ion mode.The limits of detection and quantification for nicotine were 0.071 ng/L and 0.236 ng/L,respectively.