Use of Coaxial Gas Jackets to Stabilize Taylor Cones of Volatile Solutions and to Induce Particle‐to‐Fiber Transitions

Larsen, Gustavo; Spretz, Ruben; Velarde-Ortiz, Raffet

doi:10.1002/adma.200306021

Cited by 120 publications

(98 citation statements)

References 14 publications

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“…During electrospinning the polymer solution was fed with 4 mL h -1 through a capillary (inner diameter = 1.0 mm) using the dry ice experimental set-up described elsewhere [39]. A high voltage of 20 kV was applied to the needle tip, which was kept in a chloroform/air stream [40]. The distance between the needle tip and the cylindrical collector (diameter = 8 cm, covered with aluminium foil) was kept at 20 cm.…”

Section: Nanocomposite Scaffoldsmentioning

confidence: 99%

pH-dependent antibacterial effects on oral microorganisms through pure PLGA implants and composites with nanosized bioactive glass

et al. 2013

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Biomaterials made of biodegradable poly(-hydroxyesters) such as poly(lactide-co-glycolide) (PLGA) are known to decrease the pH in the vicinity of the implants. Bioactive glass (BG) is being investigated as a counteracting agent buffering the acidic degradation products. However, in dentistry the question arises whether an antibacterial effect is rather obtained from pure PLGA or from BG/PLGA composites, as BG has been proved to be antimicrobial. In the present study the antimicrobial properties of electrospun PLGA and BG45S5/PLGA fibres were investigated using human oral bacteria (specified with mass spectrometry) incubated for up to 24 h. BG45S5 nanoparticles were prepared by flame spray synthesis. The change in colony-forming units (CFU) of the bacteria was correlated with the pH of the medium during incubation. The morphology and structure of the scaffolds as well as the appearance of the bacteria were followed bymicroscopy. Additionally, we studied if the presence of BG45S5 had an influence on the degradation speed of the polymer. Finally, it turned out that the pH increase induced by the presence of BG45S5 in the scaffold did not last long enough to show a reduction in CFU. On the contrary, pure PLGA demonstrated antibacterial properties that should be taken into consideration when designing biomaterials for dental applications. AbstractBiomaterials made of biodegradable poly(α-hydroxyesters) like poly(lactide-co-glycolide) (PLGA) are known to decrease the pH in the vicinity of the implants. Bioactive glass (BG) is being investigated as a counteracting agent buffering the acidic degradation products.However, in dentistry the question arises whether an antibacterial effect is rather obtained from pure PLGA or from BG/PLGA composites, as BG has been proved antimicrobial. In the present study the antimicrobial properties of electrospun PLGA and BG45S5/PLGA fibres were investigated using human oral bacteria (specified with mass spectrometry) incubated for up to 24 h. BG45S5 nanoparticles were prepared by flame spray synthesis. The change in colony-forming units (CFU) of the bacteria was put into correlation with the pH of the medium during incubation. Morphology and structure of the scaffolds as well as the appearance of the bacteria were followed by microscopy. Additionally, we studied if the presence of BG45S5 had an influence on the degradation speed of the polymer. Finally, it turned out that the pH increase induced by BG45S5 presence in the scaffold did not last long enough to show a reduction in CFU. On the contrary, pure PLGA demonstrated antibacterial properties that should be taken into consideration when designing biomaterials for dental applications.

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Section: Nanocomposite Scaffoldsmentioning

confidence: 99%

pH-dependent antibacterial effects on oral microorganisms through pure PLGA implants and composites with nanosized bioactive glass

et al. 2013

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“…Since the stabilized compound Taylor cone and the initial jet are the requirements for the co-axial electrospinning, high vapor pressure solvents may also not be used in the sheath solution as they may produce unstable Taylor cones [35] and lead to multiple jets due to fast evaporation. Such unstable Taylor cones can cause the formation of irregular core-sheath structures as well and result in separate fibers from the two solutions.…”

Section: Core-shell Fibers From Co-axial Electrospinningmentioning

confidence: 99%

“…Many model proteins and biomolecules encapsulated in core-shell fibers were investigated. Cells were also tried to be electrospun in fibers via coaxial electrospinning [65,72] Yi et al [73] formed biodegradable poly(glycerol sebacate) (PGS)/ PLLA composite fibers by coaxial electrospinning from 15% PGS/5% PLLA and 10% PLLA in 1,1,1,3,3,3-hexafluoropropanol as the inner and outer solutions, respectively, and the fibrous scaffold exhibited good compatibility with human microvascular endothelial cells.…”

Section: Core-shell Fibers In Tissue Engineering Scaffoldsmentioning

confidence: 99%

Core-shell Fibers for Biomedical Applications-A Review

Elahi¹,

Wang²,

Guan³

et al. 2013

J Bioeng Biomed Sci

111

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Now is the age of high-tech research and development. Different types of fibers have been produced in the last decades for the benefit of human needs. Core-shell nanofibers are a revolutionary development in the field of science and technology. Preparation of nanoscale fibers in a core-shell configuration, using two dissimilar materials, via a novel technique of electrospinning has presented unusual potential for use in many novel applications. The studies have addressed issues related to the technology involved and examined the suitability of the technique for producing unique nanoscale morphologies involving variety of materials. Numerous studies have been published on the preparation of core-shell nanofibers by electrospinning process for developing novel structures for new applications. No major review of the co-axial electrospinning process has appeared to the knowledge of the authors but is needed in order to develop a fuller understanding of the status of work in this field. After a brief introduction to the conventional electrospinning process, this paper focuses on the preparation and uses of core-shell fibers by electrospinning studies published to date. It attempts to categorize them in terms of the approaches adopted, and highlights the knowledge gained with respect to the material and process parameters that impact the size and the uniformity of the core-shell nanofibers obtained.

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“…In the conventional air blowing process, for fabrication of micron-scale fibers with final average diameter near 5 lm, air with initial speed of about 200 m/s is used, comparable to the speed of an airplane [16]. For manufacturing of sub-micron fibers the so called ''blowing assisted electrospinning process'' was proposed [8], [17,18]. In this process, the electric force is the dominating factor, while the gas-blowing feature can assist in controlling evaporation and crystallization of the polymer solution or melt.…”

Section: Introductionmentioning

confidence: 99%

“…However, the high temperature of the blown air instigated difficulties in controlling fiber formation from solution due to fast solvent evaporation rate and its effect on a rapid viscosity increase [8], [17]. Confining the capillary tip in a solvent-saturated atmosphere could prevent premature solvent evaporation, but the tip could be blocked due to polymer crystallization that could be provoked by the cooling of air or solvent vapors spout [18]. Analysis of patent information [19][20][21][22][23] suggests drawing a conclusion that in all hitherto invented devices and apparatuses for the electro-blown spinning processes, the employed gas stream provides the majority of the forwarding forces in the initial stages of electrospinning of the fibers.…”

Section: Introductionmentioning

confidence: 99%

Application of gentle annular gas veil for electrospinning of polymer solutions and melts

Rein

Cohen

Ronen

et al. 2009

Polymer Engineering & Sci

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A novel experimental device for elevated‐temperature electrospinning of highly volatile and quickly crystallizing polymer solutions and melts was developed. The main parameters of gentle annular gas veil in electrospinning process were studied. The influence of electrical conductivity of solvent on the diameter of electrospun fibers from ultra‐high molecular weight polyethylene was experimentally determined. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

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Use of Coaxial Gas Jackets to Stabilize Taylor Cones of Volatile Solutions and to Induce Particle‐to‐Fiber Transitions

Cited by 120 publications

References 14 publications

pH-dependent antibacterial effects on oral microorganisms through pure PLGA implants and composites with nanosized bioactive glass

pH-dependent antibacterial effects on oral microorganisms through pure PLGA implants and composites with nanosized bioactive glass

Core-shell Fibers for Biomedical Applications-A Review

Application of gentle annular gas veil for electrospinning of polymer solutions and melts

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