Atividade antifúngica de nanofibras de policaprolactona/nistatina: estudo in vitro e in vivo / Antifungal activity of polycaprolactone/nystatin nanofibers: in vitro and in vivo study

Este estudo avaliou a eficácia in vitro e in vivo de mantas de nanofibras (NF) de policaprolactona (PCL) incorporadas com nistatina (NIS) no tratamento da estomatite protética (EP) em modelos animais. NF foram sintetizadas com diferentes concentrações de NIS, totalizando quatro soluções: PCL puro, PCL/NIS 0,045 g, PCL/NIS 0,090 g e PCL/NIS 0,225 g. A liberação da NIS foi analisada por espectroscopia Ultravioleta-Visível. A capacidade das mantas de inibirem o biofilme de Candida albicans, principal fator etiológico da EP, dividindo-se cinco grupos (N=5) compostos por um grupo com controle de células de C. albicans e com PCL puro, além das três concentrações de NIS. A seguir, foi analisada a viabilidade celular em queratinócitos humanos (HaCat) por meio do teste colorimétrico de resazurina. Cinco grupos foram divididos (N=10): controle celular, PCL puro e as três concentrações de NIS. Em modelos animais de ratos Wistar albinos (N=18), dispositivos palatinos (DP) de resina acrílica foram confeccionados simulando próteses totais e utilizados para a indução da EP. Para isso, DP contaminados com C. albicans foram cimentados na região molar da cavidade bucal dos animais e permaneceram em boca por 48 h. Após esse período, os DP foram removidos e os animais foram divididos em três grupos: (C) controle; (B1) com tratamento por mantas de PCL/NIS 0,045 g e (B2) PCL/NIS 0,225 g, com N=6. Então novos DP, livres de contaminação, foram cimentados na cavidade oral dos animais e permaneceu por mais 48 h. Após esse período, os animais foram eutanasiados, a contagem de UFC/ mL foi realizada e os palatos foram coletados para a análise histológica. A curva padrão de NIS obtida apresentou R2 de 0,99. As três concentrações de NF apresentaram liberação de NIS, com pico no tempo de 6 h e valores de 66,26 µg/ mL para PCL/NIS 0,045 g, de 333,87 µg/ mL para PCL/NIS 0,090 g e 436,51 µg/ mL para PCL/NIS 0,225 g, constantes até o fim do experimento. Os grupos com NIS reduziram em 2,5 log10 de crescimento do biofilme fúngico em relação aos grupos sem tratamento, Controle e PCL, sem diferença estatística significativa. Não foi observada citotoxicidade nas células HaCat, com viabilidade celular de 93,7% para PCL/NIS 0,045 g, 72,6% para PCL/NIS 0,090 g e 72,4% para PCL/NIS 0,225 g. A indução da EP nos três grupos foi possível e, porém, sem redução significativa na contagem de UFC/ mL de C. albicans nos grupos B1 e B2. Na análise histológica do grupo C pôde-se observar infiltração de hifas de Candida na camada queratinizada, presença de células inflamatórias formando micro abscessos e um discreto infiltrado inflamatório no tecido conjuntivo subjacente ao epitélio infectado. Nos grupos B1 e B2 não foram encontradas alterações epiteliais, concluindo-se que as NF demonstraram atividade antifúngica in vitro e foram efetivas na prevenção da penetração de hifas no tecido palatino de animais com DP (AU)

This study evaluated the in vitro and in vivo efficacy of nanofiber (NF) mats of polycaprolactone (PCL) incorporated with nystatin (NIS) in the treatment of denture stomatitis (DS) in animal models. NFs were synthesized with different concentrations of NIS, totaling four solutions: pure PCL, PCL/NIS 0.045 g, PCL/NIS 0.090 g, and PCL/NIS 0.225 g. The release of NIS was analyzed by Ultraviolet-Visible spectroscopy. The ability of the mats to inhibit Candida albicans biofilm, the main etiological factor of DS, was assessed by dividing five groups (N=5) composed of a group with C. albicans cell control and with pure PCL, in addition to the three concentrations of NIS. Next, cell viability in human keratinocytes (HaCat) was analyzed using the resazurin colorimetric test. Five groups were divided (N=10): cell control, pure PCL, and the three concentrations of NIS. In albino Wistar rat animal models (N=18), palatal devices (PD) made of acrylic resin were fabricated to simulate total prostheses and used to induce DS. For this, PD contaminated with C. albicans were cemented in the molar region of the animals' oral cavity and remained in the mouth for 48 hours. After this period, the PDs were removed, and the animals were divided into three groups: (C) control; (B1) treated with PCL/NIS 0.045 g mats, and (B2) PCL/NIS 0.225 g, with N=6. Then new, uncontaminated PDs were cemented in the animals' oral cavity and remained for another 48 hours. After this period, the animals were euthanized, UFC/ mL counts were performed, and the palates were collected for histological analysis. The standard NIS curve obtained showed an R2 of 0.99. The three concentrations of NF showed NIS release, with a peak at 6 h and values of 66.26 µg/ mL for PCL/NIS 0.045 g, 333.87 µg/ mL for PCL/NIS 0.090 g, and 436.51 µg/ mL for PCL/NIS 0.225 g, remaining constant until the end of the experiment. The groups with NIS reduced fungal biofilm growth by 2.5 log10 compared to the untreated groups, Control and PCL, with no significant statistical difference. No cytotoxicity was observed in HaCat cells, with cell viability of 93.7% for PCL/NIS 0.045 g, 72.6% for PCL/NIS 0.090 g, and 72.4% for PCL/NIS 0.225 g. Induction of DS in the three groups was possible; however, there was no significant reduction in UFC/ mL counts of C. albicans in groups B1 and B2. Histological analysis of group C revealed infiltration of Candida hyphae in the keratinized layer, presence of inflammatory cells forming micro abscesses, and a discreet inflammatory infiltrate in the connective tissue underlying the infected epithelium. No epithelial alterations were found in groups B1 and B2, concluding that NFs demonstrated in vitro antifungal activity and were effective in preventing hyphal penetration into palatal tissue in animals with PD.(AU)

Pharmacodynamic evaluation of Polygonum capitatum nanofiber functional dressing / 中国药房

OBJECTIVE To evaluate the efficacy of the functional dressing of Polygonum capitatum nanofibers （P-PVP-PCL）. METHODS P-PVP-PCL were prepared by electrospinning technology， and the microstructure of P-PVP-PCL was observed. The antibacterial activity and antioxidant activity of P-PVP-PCL and its effects on the survival rate， adhesion and migration rate of mouse fibroblast L929 cells were investigated. The effects of medical gauze dressing， blank nanofiber dressing （PVP-PCL） and P- PVP-PCL on the healing rate of the wound were investigated by establishing the back skin wound model of rats. The pathological changes of the wound tissue and collagen fiber deposition were observed， as well as the number of platelet endothelial cell adhesion molecule-1 （CD31） positive blood vessels and the expression of transforming growth factor-β （TGF-β） protein in wound tissue. RESULTS P-PVP-PCL had a smooth surface and a double-layer structure at the cross-section. The inhibition rates of P-PVP-PCL against Staphylococcus aureus and Escherichia coli were （98.88±0.66）% and （94.75±1.41）% ， respectively. The antioxidant activity of P-PVP-PCL was （83.69±1.56）%， and the cell activity of the P-PVP-PCL group was significantly higher than those of the control group and PVP-PCL group （P＜0.05）. Compared with medical gauze dressings， P-PVP-PCL was more conducive to L929 cell adhesion； at 48 hours， the cell scratches in this group had basically healed. Compared with the medical gauze dressing group， the wound healing rates of the PVP-PCL group and the P-PVP-PCL group were significantly increased （P＜0.05）. On the 14th day of intervention， the wounds in the P-PVP-PCL group had basically healed， there was no dermal necrosis in the wound tissue， and the collagen fibers were arranged relatively neatly and the density was relatively uniform. The number of CD31 positive blood vessels and the expression of TGF-β protein showed a downward trend compared with the 7th day of intervention， and the number of CD31 positive blood vessels was significantly lower than those of the medical gauze dressing group and PVP-PCL group （P＜0.05）， but the protein expression of TGF- β was significantly higher than those of the medical gauze dressing group and the PVP-PCL group （P＜0.05）. CONCLUSIONS P-PVP-PCL has good antibacterial and antioxidant activity in E-mail：444096585@qq.com vitro， and can promote the proliferation， adhesion and migration of L929 cells. It can promote wound healing of rats in vivo.

An injectable hydrogel/staple fiber composite for sustained release of CA4P and doxorubicin for combined chemotherapy of xenografted breast tumor in mice / 南方医科大学学报

OBJECTIVE@#To prepare an injectable hydrogel/staple fiber composite loaded with combretastain A-4 disodium phosphate (CA4P) and doxorubicin (DOX) and evaluate its antitumor efficacy via intratumoral injection.@*METHODS@#DOX-loaded PELA staple fibers (FDOX) were prepared using electro-spinning and cryo-cutting, and the drug distribution on the surface of the fibers was observed using a fluorescence microscope, and the encapsulation efficiency and loading capacity of FDOX were determined with a fluorospectro photometer. The fibers were then dispersed in CA4P-loaded PLGA-PEG-PLGA tri-block polymer solution at room temperature to obtain the hydrogel/staple fiber composite (GCA4P/FDOX). The thermo-sensitivity of this composite was determined by a test tube inverting method. An ultraviolet spectrophotometer and a fluorospectrophotometer were used to detect the release profile of CA4P and DOX, respectively. We observed in vivo gel formation of the composite after subcutaneous injection in mice. The in vitro cytotoxicity of GCA4P/FDOX composite in MCF-7 and 4T1 cells was assessed using cell Counting Kit-8 (CCK-8) reagent. In a mouse model bearing breast tumor 4T1 cell xenograft, we evaluated the antitumor efficacy of the composite by monitoring tumor growth within 30 days after intratumoral injection of the composite. HE staining, immunohistochemistry for Ki67 and immunofluorescence (TUNEL) assay were used for pathological examination of the tumor tissues 21 days after the treatments.@*RESULTS@#The average length of FDOX was 4.0±1.3 μm, and its drug loading capacity was (2.69±0.35)% with an encapsulation efficiency of (89.70±0.12)%. DOX was well distributed on the surface of the fibers. When the temperature increased to 37 ℃, the composite rapidly solidified to form a gel in vitro. Drug release behavior test showed that CA4P was completely released from the composite in 5 days and 87% of DOX was released in 30 days. After subcutaneous injection, the composite solidified rapidly without degradation at 24 h after injection. After incubation with GCA4P/FDOX for 72 h, only 30.6% of MCF-7 cells and 28.9% of 4T1 cells were viable. In the tumor-bearing mice, the tumor volume was 771.9±76.9 mm3 in GCA4P/FDOX treatment group at 30 days. Pathological examination revealed obvious necrosis of the tumor tissues and tumor cell apoptosis induced by intratumoral injection of G4A4P/FDOX.@*CONCLUSION@#As an efficient dual drug delivery system, this hydrogel/staple fiber composite provides a new strategy for local combined chemotherapy of solid tumors.

Research progress on electrospinning technology in wound dressing / 国际生物医学工程杂志

Electrospinning is a technology that uses a high-voltage electrostatic field to prepare ultrafine fibers, which are widely used in tissue engineering and biomedical fields because the nanofiber materials prepared have strong mechanical strength and can mimic the structure of extracellular matrix (ECM). In this paper, the characteristics of synthetic and natural polymers for the preparation of medical dressings by electrostatic spinning were described in detail, and their advantages and disadvantages were compared according to the source of the matrix polymer. Several kinds of loaded substances used in wound dressing were summarized, the mechanism of the dressing to promote wound healing was described, and the problems of making electrospinning wound dressing were analyzed, in order to promote the further development of electrospinning technology in the field of wound dressing.

Application and Prospect Analysis of Preparation Technology in Improving Antibacterial Activity of Traditional Chinese Medicine / 中国实验方剂学杂志

Pathogenic bacterial infection is one of the main clinical symptoms. Antibiotics are widely used in clinical practice to inhibit or kill the bacteria， fungi and other pathogenic microorganisms. However， with the massive use of antibiotics， drug-resistant strains continue to appear that make the antibacterial situation is becoming increasingly severe. Due to the advantages of multiple targets， multiple pathways and multiple components， traditional Chinese medicine （TCM） have gradually attracted more attention and were used in antibacterial treatment. However， some antimicrobial TCM have problems such as low solubility， poor stability， and low bioavailability. Improving and enhancing the antibacterial activity of TCM through preparation technology is one of the effective solutions. Based on this， two aspects of unilateral antibacterial TCM preparation technology and combination antibacterial preparation technology are introduced， including inclusion technology， nanotechnology， electrospinning， 3D printing and others. Distinctive features and specific application effects of these preparation technologies are explained firstly， and then their advantages and disadvantages are compared and analyzed. The review can be a useful reference for improving the antibacterial activity of TCM.

Biomateriales compuestos para restauración ósea obtenidos mediante tecnologías basadas en el uso del campo electromagnético / Composite biomaterials for bone restoration obtained by technologies based on the use of the electromagnetic

Introducción: El panorama demográfico en el mundo está cambiando. La población mayor de 60 años es el segmento que está creciendo más rápidamente y en el que las enfermedades del tejido óseo se presentan con más frecuencia, lo que aumenta la demanda de materiales y tecnologías apropiadas para restaurar estos tejidos. Objetivo: Analizar la información que se ha generado sobre el desarrollo de biomateriales compuestos para la reparación ósea, con énfasis en la identificación de las tecnologías emergentes basadas en el uso del campo electromagnético, sus aplicaciones y potencialidades. Métodos: Se consultaron trabajos científicos publicados en libros, revistas, patentes y tesis. El 80 por ciento de la documentación seleccionada pertenece al periodo 2010-2019. Análisis e integración de la información: Los métodos identificados fueron clasificados en cinco grupos: electrodeposición química, ya sea por electrólisis, electroforesis o síntesis electroforética in situ; electroporación; electrohilado; control magnético distal y bioestimulación electromagnética de células y tejidos, directamente o por la introducción de dispositivos que convierten la energía electromagnética en energía mecánica. Conclusiones: Estos métodos permiten la conformación de matrices celulares y acelulares compuestas y, además, dispositivos bioestimuladores con control de los parámetros de construcción y acción, de tal manera, que se logran procesos con mayor grado de reproducibilidad y a la medida de los requerimientos específicos para cada paciente(AU)

Introduction: The global demographic panorama is changing. The population aged over 60 years is the fastest growing segment, as well as the one where bone tissue diseases are most common, increasing the demand of appropriate materials and technologies to restore those tissues. Objective: To analyze the information so far generated about the development of composite biomaterials for bone repair, with an emphasis on the identification of emerging technologies based on the use of the electromagnetic field, its applications and potential. Methods: An analysis was performed of scientific papers published in books, journals, patents and theses. Of the documentation selected, 80 percent was from the period 2010-2019. Data analysis and integration: The methods identified were classified into five groups: chemical electrodeposition, be it by in situ electrophoretic synthesis, electrolysis or electrophoresis; electroporation; electrospinning; distal magnetic control and electromagnetic biostimulation of cells and tissues, either directly or incorporating devices which convert electromagnetic energy into mechanical energy. Conclusions: These methods permit the conformation of composite cellular and acellular matrices as well as biostimulator devices controlling construction and action parameters in such a way that the processes obtained display greater reproducibility and are more in keeping with the specific requirements of each patient(AU)

Advantages and characteristics of electrospun aligned nanofibers as scaffolds for tissue engineering / 中国组织工程研究

BACKGROUND: Tissue engineering technology relies on biomaterial scaffolds as supporting structures for tissue repair and regeneration. Among these biological scaffolds, electrospun fiber scaffolds have been widely applied in regenerative medicine owing to their mimicry of the natural structure of extracellular matrix. OBJECTIVE: To summarize the current application of electrospun aligned nanofibers in the field of tissue engineering. METHODS: Relevant articles included in PubMed from January 2010 to March 2020 were searched by the first author, with key words of “electrospinning; aligned nanofibers; tissue engineering; regenerative medicine; bioactive materials” in English. Relevant articles included in CNKI and Wanfang database from January 2010 to March 2020 were searched with key words of “electrospinning; aligned nanofibers; oriented fiber; tissue engineering; tissue regeneration” in Chinese. Finally, 67 articles were included for review. RESULTS AND CONCLUSION: Electrospinning is a simple and effective technology for the preparation of nanomaterials. In recent years, many kinds of natural materials or polyester materials with good biocompatibility and biodegradability have been prepared into electrospun nanofiber scaffolds with different structures by electrospinning technology, which are widely used in tissue engineering, regenerative medicine and other fields. Among them, the electrospun oriented nanofiber scaffolds, inspired by the highly directional characteristics of natural extracellular matrix, have highly consistent fiber arrangement direction, which can promote cell adhesion and migration through contact guidance, and the combination with cells or growth factors can further promote cell proliferation and differentiation, and ultimately achieve tissue regeneration in nerve, myocardium, tendon and bone tissue. In the field of regeneration and wound healing, it has great potential and wide application prospect.

Analysis of the association of parameters in the formation of ultrafine fibers from PEI and PMMA / Análise da associação de parâmetros na formação de fibras ultrafinas de PEI e PMMA

Objective: The aim of the study was to fabricate and morphologically characterize ultrafine Polyetherimide fibers (PEI) associated with Polymethylmethacrylate (PMMA) ­ PP (group formed by the association of PEI with PMMA), produced by the electrospinning process. Material and Methods: A solution of PEI (0.562 g) + PMMA (0.377 g) dissolved in 2.5 mL of chloroform, 0.85 mL of Dimethylformamide (DMF) and 0.85 mL of 1.1.2.2 Tetrachloroethane (TCE) was prepared. For the electrospinning process, different continuous voltages (10 to 18 kV) and two different distances (8 and 12 cm) between the needle tip and the collecting apparatus were used, giving rise to 6 distinct groups of ultrafine fibers (PP 1 to 6) that were observed in Scanning Electron Microscopy to check for defects and calculate the average diameter of the fibers. Results: The best parameter, the parameter that was most effective for the production of fibers, observed was subjected to Energy Dispersion X-ray Spectroscopy (EDS), X-ray Diffraction (XRD) and Contact Angle Analysis tests. The data were analyzed using the ANOVA and Tukey test (p <0.05). From the comparative analysis of the pre-established parameters, the pattern of PP4 ultrafine fibers was shown to be more effective. Conclusion: The PP4 standard (13 kV ­ 12 cm) had an average diameter of 0.37 µm. An adequate parameter to electrospinning was able to produce ultrafine fibers of PMMA/PEI (AU)

Introdução: O objetivo do estudo foi sintetizar e caracterizar morfologicamente fibras ultrafinas de Polieterimida (PEI) associadas ao Polimetilmetacrilato (PMMA) - PP (grupo formado pela associação de PEI com PMMA), produzidas pelo processo de eletrofiação. Material e Métodos: Foi preparada uma solução de PEI (0,562 g) + PMMA (0,377 g) dissolvido em 2,5 mL de clorofórmio, 0,85 mL de Dimetilformamida (DMF) e 0,85 mL de 1.1.2.2 Tetracloroetano (TCE). Para o processo de eletrofiação, foram utilizadas diferentes tensões contínuas (10 a 18 kV) e duas distâncias diferentes (8 e 12 cm) entre a ponta da agulha e o aparelho coletor, dando origem a 6 grupos distintos de fibras ultrafinas (PP 1 a 6) que foram observados em Microscopia Eletrônica de Varredura para verificar defeitos e calcular o diâmetro médio das fibras. Resultados: O melhor parâmetro, o parâmetro mais eficaz para a produção de fibras, observado foi submetido aos testes de Espectroscopia de Dispersão de Energia (EDS), Difração de Raios X (DRX) e Análise do Ângulo de Contato. Os dados foram analisados pela ANOVA e teste de Tukey (p <0,05). A partir da análise comparativa dos parâmetros pré-estabelecidos, o padrão das fibras ultrafinas PP4 mostrou-se mais eficaz. Conclusão: O padrão PP4 (13 kV - 12 cm) apresentou diâmetro médio de 0,37 µm. Um parâmetro adequado para eletrofiação foi capaz de produzir fibras ultrafinas de PMMA / PEI. (AU)

Development of electrospun-based polyetherimide fibers and diameter analysis for potential use in dental materials / Desenvolvimento de fibras de polieterimida à base de eletrofiação e análise de diâmetro para uso potencial em materiais odontológicos

Objetives: this study aimed to fabricate electrospun-based polyetherimide (PEI) fibers, under controlled parameters, and to perform a diameter analysis for potential mechanical improvement of dental materials. Material and Methods: PEI pallets (0.75 g) were dissolved in 2 mL of chloroform and then processed by electrospinning, under a flow rate of 1mLh-1, three different electrical voltages (10kV, 15kV and 20kV) and three distances (10 cm, 15 cm and 18 cm) between the needle tip and collector. These parameter combinations resulted in nine experimental groups that were analyzed using scanning electron microscopy (SEM) and image processing program for diameter measurement. Statistical analysis was performed using two-way ANOVA with post-hoc Tukey (5% significance). Results: from SEM images it was possible to observe formation of solid, misaligned and flawless defect-free fibers. And from the statistical analysis, distance (p = 0,0026) and the electric tension (p = 0,0012) showed a significant difference, but not for interaction between then (p = 0,4486). Conclusion: thus, it can be concluded that there is a possibility of the morphology control of PEI electrospun fibers, such as diameter, that can be used for a variety of applications such as incorporation in dental materials in order to improve its properties. (AU)

Objetivos: o objetivo deste estudo foi fabricar fibras de polieterimida à base de eletrofiação (PEI), sob parâmetros controlados, e realizar uma análise de diâmetro para potencial aprimoramento mecânico de materiais odontológicos. Material e métodos: paletes de PEI (0,75 g) foram dissolvidos em 2 mL de clorofórmio e processados pela eletrofiação, sob uma razão de fluxo de 1 mLh-1, três tensões elétricas diferentes (10 kV, 15 kV e 20 kV) e três distâncias (10 cm, 15 cm e 18 cm) entre a ponta da agulha e o coletor. Essas combinações de parâmetros resultaram em nove grupos diferentes que foram analisadas usando microscopia eletrônica de varredura (MEV) e programa de processamento de imagem para medição de diâmetro. Resultados: a partir das imagens de MEV foi possível observar a formação de fibras sólidas, desalinhadas e sem defeitos. E a partir da análise estatística, a distância (p = 0,0026) e a tensão elétrica (p = 0,0012) apresentaram diferença significativa, mas não para interação entre elas (p = 0,4486). Conclusão: assim, pode-se concluir que existe a possibilidade de controle da morfologia das fibras eletrofiadas PEI, como o diâmetro, que pode ser utilizado para uma variedade de aplicações, como incorporação em materiais dentários, a fim de melhorar suas propriedades (AU)

Electrospinning: Avances y aplicaciones en el campo de la biomedicina / Electrospinning: Advances And Applications In The Field Of Biomedicine

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.

Effect of PLGA electrospinning membrane carrying paclitaxel-liposomes on proliferation and differentiation of neural stem cells / 吉林大学学报(医学版)

Objective: To investigate the effects of polyactic-co-glycolic (PLGA) electrospinning membrane carrying paclitaxel liposomes with different concentrations on the proliferation and differentiation of the neural stem cells (NSCs) â™ and to evaluate the feasibility of PLGA electrospinning membrane carrying paclitaxel liposomes in the tissue engineering repair of spinal cord injury. Methods: The paclitaxel liposomes and PLGA were mixed in different proportions and the electrospinning technique was used to construct 1, 5 and 10 ng • L electrospinning membrane carrying paclitaxel liposomes. The NSCs were isolated and purified from the fetal rat brain tissue. The diameters of PLGA electrospinning membrane carrying paclitaxel-liposomes in various groups were detected by scanning electron microscope (SEM) â™ and the isolated and purified NSCs were identified by immunofluorescence staining. The NSCs were cultured in PLGA electrospinning membrane carrying paclitaxel-liposomes with different concentrations (0, 1, 5 and 10 p. g • L ) as PLGA electrospinning membrane group and PLGA electrospinning membrane carrying 1, 5 and 10 n g • L paclitaxel-liposomes groups. The proliferation levels of the NSCs in various groups was detected by MTT method, and the expression levels of Tuj-1 and GFAP mRNA in the NSCs in various groups were detected by RT-PCR method. Results: The PIjGA electrospinning membrane carrying paclitaxel-liposomes were white thin films. The SEM results showed that there was no statistical differences in the fiber diameters of PLGA electrospinning membrane carrying paclitaxel-liposomes between various groups ( P > 0.05). The immunofluorescence staining results showed that the cells isolated from fetal rat brain tissue were spherical and positive expression of Nestin protein. The MTT assay results showed that the proliferation level of NSCs in PLGA electrospinning membrane carrying 5 fxg ' L paclitaxel liposomes group was higher than those in the other three groups (P<"0.05). The RT-PCR results showed that compared with PLGA electrospinning membrane group, the expression level of Tuj-1 mRNA in the NSCs in PLGA electrospinning membrane carrying 5 pg ∗ L paclitaxel-liposomes group was increased ( P< 0. 05) and the expression level of GFAP mRNA in the NSCs in PLGA electrospinning membrane carrying 5/ig ∗ L paclitaxel-liposomes group was decreased ( P < 0.05 ). Conclusion: Medium concentration of paclitaxel can promote the proliferation of NSCs and induce the differentiation of NSCs into the neurons. PIjGA electrospinning membrane carrying medium concentration of paclitaxel-liposomes has certain application value in the repair of spinal cord injury.

Construction of periodontal biomimetic membrane with electrospun poly(Lactic-co-glycolic acid) nanofibers and electrosprayed chitosan microspheres / 中国组织工程研究

BACKGROUND: When the teeth are separated from the alveolar fossa, the periodontal membrane breaks, and the residual periodontal membrane on the avulsed tooth root surface changes from three-dimensional to two-dimensional, thus losing the role of scaffold, and leading to root bone adhesion after replantation of avulsed tooth. How to develop a three-dimensional sustained-release scaffold material that can adhere to the root surface with a certain thickness and strength is one of the key factors for successful regeneration of avulsed tooth periodontal membrane. OBJECTIVE: To construct a three-dimensional periodontal biomimetic membrane that can adhere to the avulsed tooth root surface and allow sustained-release of growth factors. METHODS: Poly(lactic-co-glycolic acid) (PLGA) membrane was prepared using electrospinning technique. The effects of dichloromethane and dimethylformamide mixture, hexafluoroisopropanol, and trichloromethane on electrospun membrane were investigated to obtain the optimal electrospinning solvent. Chitosan microspheres were prepared by electrospray and ion cross-linking techniques. The effects of molecular weight (50, 000, 100, 000) and mass concentration (10, 20 g/L) of chitosan, sodium tripolyphosphate concentration (2%, 5%, 10%) and voltage (14, 28 kV) on chitosan microspheres were studied to screen the optimum parameters. Chitosan microspheres containing stromal cell-derived factor-1 (optimal parameter design) were constructed. The release rate of stromal cell-derived factor-1 alpha in vitro was determined. First, the root surface of teeth was wrapped with electrospun PLGA membrane, then chitosan microspheres were dripped on the surface, and finally the surface was wrapped with a thin layer of electrospun PLGA. Thus, PLGA-chitosan-PLGA biomimetic membrane was constructed. RESULTS AND CONCLUSION: Electrospun PLGA membrane prepared with hexafluoroisopropanol as electrospinning solvent had the smallest average diameter and the largest porosity. When the relative molecular weight of chitosan was 50, 000 and the mass concentration was 20 g/L, the size of chitosan microspheres was basically the same, and the average diameter was 366. 6 μm. In addition, chitosan microsphere had good monodispersity, fullness, and stability. Chitosan microspheres formed under 28 kV voltage and were more in line with the requirements of biomimetic membrane for avulsed tooth. The surface of microspheres prepared by 5% sodium tripolyphosphate had medium-sized pores, which are most conducive to clinical periodontal membrane regeneration. Chitosan microspheres can sustainably release stromal cell derived factor 1alpha for about 1 month. In this study, we constructed a three-dimensional PLGA-chitosan-PLGA periodontal biomimetic membrane that can adhere to the avulsed tooth root surface and allow sustained-release of growth factors and obtained the optimal parameters of constructing the periodontal biomimetic membrane. Based on the PLGA-chitosan-PLGA periodontal biomimetic membrane, the effect and mechanism of tissue engineering on replantation of avulsed tooth can be further studied.

A novel hydroxyapatite fiber scaffold for three-dimensional cell culture / 中国组织工程研究

BACKGROUND: The dense microstructure of biological scaffolds and the limitation of cell growth microenvironment are the two major difficulties in the application of biological scaffolds in bone tissue repair. OBJECTIVE: To prepare fluffy hydroxyapatite/polylactic acid composite fiber scaffold, so that cells can easily enter into the scaffold and to realize three-dimensional culture of bone marrow mesenchymal stem cells. METHODS: Fluffy hydroxyapatite/polylactic acid composite scaffold was prepared by using modified electrospinning technology combined with biomineralization. The physical and chemical properties of the fiber scaffold were measured and observed. Human bone marrow mesenchymal stem cells were inoculated on the fluffy hydroxyapatite/polylactic acid composite scaffold and traditional hydroxyapatite/polylactic acid composite scaffold. Cell proliferation, adherence and morphological changes were detected. RESULTS AND CONCLUSION: (1) The thickness of hydroxyapatite coating in the fluffy hydroxyapatite/polylactic acid composite scaffold was about 8.3 µm, most of hydroxyapatite fibers were in discrete state with a diameter of 8-14 µm. The fibers were connected by pores, and the pore diameter was (65±35) µm. The surface area, porosity and water absorption of the scaffold were significantly higher than those of the traditional scaffold (P < 0.01). (2) After 12 hours of culture, the adherence of bone marrow mesenchymal stem cells on the two scaffolds was similar, 83% and 81% cells adhered on the traditional and fluffy scaffolds, respectively. (3) After 7 days of culture, the number of proliferated cells in the fluffy hydroxyapatite/polylactic acid composite scaffold was significantly more than that in the traditional hydroxyapatite/polylactic acid composite scaffold (P < 0.01). (4) After 7 days of culture, FDA staining and scanning electric microscopy showed that cell-cell independent shape appeared in the traditional scaffold. A large number of cells appeared in the fluffy scaffold and grew into cell clusters with high cell activity, which formed a cell-fiber construction. These results indicate that this new type hydroxyapatite/polylactic acid composite scaffold is beneficial for cell entry and proliferation.

A drug-loading system for electrospinning wound repair: Component selection and construction strategy / 中国组织工程研究

BACKGROUND: As an excellent material in recent years, electrospinning membrane provides a new method to promote the healing of wound. Based on the diversity of its fibrous base and active components, it is flexible to build a drug delivery system for electrospinning wound repair. OBJECTIVE: To summarize the mechanism and functional characteristics of the components belonging to electrospinning fiber membrane drug-loading system, and to guide the selection of construction strategies for wound healing materials. METHODS: The literature search was performed in Web of Science, PubMed, CNKI, and WanFang databases. The key words were “electrospinning, wound dressing, nanofibers, wound healing, drug deliver”. Ninety articles were included in this review finally. RESULTS AND CONCLUSION: The construction strategies of electrospinning wound repair drug-delivery system were diverse. Through electrospinning technology, different polymers could be used to carry stem cell components or other small functional bioactive “drugs”, thus constructing a variety of effective composite systems. These materials might be applied to all aspects of the wound healing process, and finally achieve the purpose of promoting wound soft tissue healing. The excellent drug-loading system/drug-loading strategies have expanded the vision of wound treatment. Compared with traditional hydrogel and accessory treatment products, the multi-mechanism, function and possibility characteristics of electrospinning wound repair drug-delivery system determined its advantages in wound treatment.

Application and significance of nanofibrous macroporous scaffold preparation technology for bone tissue engineering / 中国组织工程研究

BACKGROUND: Bionic porous scaffolds used in bone tissue engineering requires extracellular matrix-like nanofibrous and connected macroporous structure to effectively support cell implantation, adhesion, proliferation and other behaviors, and promote tissue regeneration. OBJECTIVE: To summarize the research progress in nanorfibrous macroporous scaffold preparation technology for tissue engineering based on the latest relevant research trends. METHODS: The first author searched Web of Science, CNKI and Baidu academic databases to retrieve papers published from 2000 to 2019 with the search terms “bone tissue engineering, nanofibrous, macroporous, scaffolds” in English and Chinese, respectively. Finally, 58 articles were included in result analysis. RESULTS AND CONCLUSION: The scaffolds with nanofibrous structures are fabricated using three strategies, including electrospinning, thermally induced phase separation, and self-assembly process. However, bone scaffold fabricated by a single strategy failed to provide interconnected macropores to simulate the microenvironment in the body, which was necessary for cell migration, growth, differentiation, proliferation, and tissue and organ regeneration. Therefore, it is now of great practical and scientific significance to develop macroporous nanofibrous scaffold using a combination of several strategies. Three-dimensional printing technique can provide precise structure and enables the customization of the internal structure and external shape of the scaffold, which promotes the development of bone tissue engineering technique.

A novel hydroxyapatite fiber scaffold for three-dimensional cell culture / 中国组织工程研究

BACKGROUND: The dense microstructure of biological scaffolds and the limitation of cell growth microenvironment are the two major difficulties in the application of biological scaffolds in bone tissue repair. OBJECTIVE: To prepare fluffy hydroxyapatite/polylactic acid composite fiber scaffold, so that cells can easily enter into the scaffold and to realize three-dimensional culture of bone marrow mesenchymal stem cells. METHODS: Fluffy hydroxyapatite/polylactic acid composite scaffold was prepared by using modified electrospinning technology combined with biomineralization. The physical and chemical properties of the fiber scaffold were measured and observed. Human bone marrow mesenchymal stem cells were inoculated on the fluffy hydroxyapatite/polylactic acid composite scaffold and traditional hydroxyapatite/polylactic acid composite scaffold. Cell proliferation, adherence and morphological changes were detected. RESULTS AND CONCLUSION: (1) The thickness of hydroxyapatite coating in the fluffy hydroxyapatite/polylactic acid composite scaffold was about 8.3μ m, most of hydroxyapatite fibers were in discrete state with a diameter of 8-14μm. The fibers were connected by pores, and the pore diameter was (65±35) μm. The surface area, porosity and water absorption of the scaffold were significantly higher than those of the traditional scaffold (P<0.01).(2) After 12 hours of culture, the adherence of bone marrow mesenchymal stem cells on the two scaffolds was similar, 83% and 81% cells adhered on the traditional and fluffy scaffolds, respectively. (3) After 7 days of culture, the number of proliferated cells in the fluffy hydroxyapatite/polylactic acid composite scaffold was significantly more than that in the traditional hydroxyapatite/polylactic acid composite scaffold (P<0.01).(4) After 7 days of culture, FDA staining and scanning electric microscopy showed that cell-cell independent shape appeared in the traditional scaffold. A large number of cells appeared in the fluffy scaffold and grew into cell clusters with high cell activity, which formed a cell-fiber construction. These results indicate that this new type hydroxyapatite/polylactic acid composite scaffold is beneficial for cell entry and proliferation.

VPA/PLGA microfibers produced by coaxial electrospinning for the treatment of central nervous system injury

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.

Preparation and characterization of naftifine-loaded poly(vinyl alcohol)/sodium alginate electrospun nanofibers

In this study, naftifine (a topical antifungal drug) loaded poly(vinyl) alcohol (PVA)/sodium alginate (SA) nanofibrous mats were prepared using the single-needle electrospinning technique. The produced nanofibers were crosslinked with glutaraldehyde (GTA) vapor. The morphology and diameter of the electrospun nanofibers were studied by scanning electron microscopy (SEM). SEM images showed the smoothness of the nanofibers and indicated that the fiber diameter increased with crosslinking and drug loading. Atomic force microscopy (AFM) images confirmed the uniform production of the scaffolds, and elemental mapping via energy dispersive X-ray spectroscopy (EDS) showed the uniform distribution of the drug within the nanofibers. An attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy study demonstrated that naftifine has sufficient secondary interactions with the polymer blend. The crosslinking treatment decreased the burst drug release effectively and the release mechanism followed Korsmeyer-Peppas Super Case-II transport. Overall, these findings suggest the potential use of naftifine-loaded PVA/SA nanofibers as a topical antifungal drug delivery system.

Fabrication Of Nanofibres By Electrospinning Using Keratin From Waste Chicken Feathers, Pva And Agnps

Objective: To prepare and characterise keratin from chicken feathers (CF), collected from the slaughter house, and to blend with poly vinly alcohol (PVA) and biosynthesised silver nanoparticles (AgNPs) and to convert into nanofibers by an elctrospinning process. Methods: The extraction of keratin from chicken feathers was done by sodium m-bisulphite. The solution was subjected to ammonium sulphate precipitation to separate keratin. The nanoparticles was synthesised using tridax procumbens. The isolated keratin and PVA was mixed in the ration 0f 50:50 with 1 ml of biosynthesised nanoparticles was blended and made into nanofibres by electrospinning technique. Results: The precipitated protein was analysed using FT-IR analysis confirming the presence of β-keratin in the sample isolated from chicken feathers and the concentration of keratin was estimated to be 1.85 g/ml. PVA solution with 4% w/v had the best film forming ability. The solution containing keratin, PVA and silver nanoparticles was prepared in various proportions. These solutions when subjected to electrospinning, fibrous network was observed in 50:50 (PVA: Keratin) ratio with 1 ml of synthesised silver nanoparticle solution. Hydrogen bonding between keratin and PVA indicated in the XRD analysis showed successful film forming of the nanofiber, the DSC analysis also showed similar results as the obtained peak was at 214 °C which is in between the characteristic heat degradation temperature of both the keratin and PVA. The thermogravimetric analysis (TGA) showed high thermal stability as the complete degradation of the nanofiber was observed at 420 °C. Incorporation of metal nanoparticles by herbal approach using tridax procumbens in the nanofibers provided the antimicrobial properties. The nanofibres obtained by electrospinning process appeared stable and continous for solutions containing no more than 50% wt of CF. The average diameter of the nanofibres increased as the CF content increased. Conclusion: Keratin isolated from the waste chicken feathers impregnated with biosyntheised silver nanoparticles using tridax procumbens and PVA can be converted into nanofibers by electrospinning process. Thus, the biocomposite nano fibers are shown as a novel eco-friendly material that must be adequately applied in the development of green composites for the biomedical applications such as wound dressings.

Drug eluting sutures: A recent update

The main use of surgical sutures is to assist closure and healing of trauma-induced as well as surgical wounds. Thisis done by upholding wound tissues together in order to facilitate the healing process. A huge variety of suturesare available for the medical purposes, e.g., bio active sutures, knot-less sutures, electronic sutures, drug-elutingsutures, anti-microbial sutures, and stem cells containing sutures. Sutures increase the capabilities to improve tissueapproximation and wound healing. Sutures with drug eluting property are the advanced type of sutures being used forsurgical purpose via delivery of drug to the specified area. Various new strategies develop the effectiveness of suturesto be used as physical entity to get better biologically active component which enables the delivery of various desirabledrugs and cells to the affected site. Ideal modified sutures should not only retain its mechanical integrity during thehealing process, but should also deliver the drugs loaded in it, in a controlled manner. These nano-structured fibers,produced by electrospinning and electrospraying techniques, offer tuneable release kinetics applicable to diversebiomedical applications. Drug eluting sutures lead to reduced surgical site infections, accelerated wound healing,reduced post-operative complications, and the most important thing is it reduces the need for supplement drugs. It willbe the biggest achievement if we get the desired concentration and effect of the loaded drug in these sutures withoutaffecting its mechanical properties. This can be achieved by enhancing/modifying the control release approaches. Thecurrent review gives updated information on recent advances in drug eluting sutures.