Melt‐spun hollow fibers: Modeling and experiments

Rovère, Anne De; Shambaugh, Robert L.

doi:10.1002/pen.10822

Cited by 27 publications

(22 citation statements)

References 14 publications

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“…On the other hand, suturability of nerve guidance channels depends both on the material mechanical properties and the tube wall thickness. Extrusion process is a flexible technique which allows a regulation of the guide geometrical features (inner diameter, wall thickness, tube length), depending on the spinneret die dimensions, the air flow within the inner cavity of the guide, the extrusion temperature and the draw ratio of the extruded hollow filament (De Rovère and Shambaugh 2001;Lipscomb 1994). The first requirement for a polymer to be manufactured into a hollow conduit by melt-extrusion is its thermal stability at the applied Fig.…”

Section: Discussionmentioning

confidence: 99%

Melt-extruded guides for peripheral nerve regeneration. Part I: Poly(ε-caprolactone)

Chiono

Vozzi

et al. 2009

Biomed Microdevices

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Melt-extruded guides for peripheral nerve repair based on poly(epsilon-caprolactone) (PCL) were realised and their physico-chemical properties were evaluated. Preliminarily, PCL cast films were found to support the attachment and proliferation of Neonatal Olfactory Bulb Ensheating Cells (NOBEC). S5Y5 neuroblastoma cells were cultured inside PCL guides in their uncoated form or coated with a non-specific adhesion protein (gelatin) and a specific peptide for nerve regeneration (poly(L-lysine)). Coating increased cell density (gelatin) and/or the cell density rate on substrates (poly(L-lysine); gelatin) as compared to uncoated guides. Various in vivo tests were carried out for the repair of small (0.5 cm), medium (1.5 cm) and long (4.5 cm) size defects in the peripheral nerves of Wistar rats. For the small nerve defects, uncoated and coated PCL guides were tested. Results from in vivo tests were subjected to histological examination after 45 days, 6 and 8 months postoperative for small, medium and large defects, respectively. Regeneration was found for small and medium size defects. For 0.5 cm defects, the coating did not affect regeneration significantly. Grip-tests also evidenced functional recovery for the 1.5 cm-long defects treated with PCL guides, after 6 months from implantation. On the other hand, mechanical stiffness of PCL conduits impaired the repair of 4.5 cm-long defects in 8-month period: the lack of flexibility of the guide to rat movements caused its detachment from the implant site. The research showed that PCL guides can be used for the successful repair of small and medium size nerve defects, with possible improvements by suitable bio-mimetic coatings.

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Section: Discussionmentioning

confidence: 99%

Melt-extruded guides for peripheral nerve regeneration. Part I: Poly(ε-caprolactone)

Chiono

Vozzi

et al. 2009

Biomed Microdevices

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“…Non-woven polystyrene fibrous matrices were produced by spunbonding. 17,18 The apparatus consisted of a Brabenderä single screw extruder, a spin pack equipped with a gear pump, and a spinneret. The extruder barrel was 19.0 mm (0.75 in.)…”

Section: Scaffoldsmentioning

confidence: 99%

Flow Perfusion Improves Seeding of Tissue Engineering Scaffolds with Different Architectures

et al. 2007

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Engineered bone grafts have been generated in static and dynamic systems by seeding and culturing osteoblastic cells on 3-D scaffolds. Seeding determines initial cellularity and cell spatial distribution throughout the scaffold, and affects cell-matrix interactions. Static seeding often yields low seeding efficiencies and poor cell distributions; thus creating a need for techniques that can improve these parameters. We have evaluated the effect of oscillating flow perfusion on seeding efficiency and spatial distribution of MC3T3-E1 pre-osteoblastic cells in fibrous polystyrene matrices (20, 35 and 50-microm fibers) and foams prepared by salt leaching, using as controls statically seeded scaffolds. An additional control was investigated where static seeding was followed by unidirectional perfusion. Oscillating perfusion resulted in the most efficient technique by yielding higher seeding efficiencies, more homogeneous distribution and stronger cell-matrix interactions. Cell surface density increased with inoculation cell number and then reached a maximum, but significant detachment occurred at greater flow rates. Oxygen plasma treatment of the fibers greatly improved seeding efficiency. Having similar porosity and dimensions, fibrous matrices yielded higher cell surface densities than foams. Fluorescence microscopy and histological analyses in polystyrene and PLLA scaffolds demonstrated that perfusion seeding produced more homogeneous cell distribution, with fibrous matrices presenting greater uniformity than the foams.

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“…The authors generally obtained tubes with various diameter dimensions and wall thickness: the extrusion processing parameters (temperature profile along the extruder, screw rotor speed, drawing rate and air flow in the inner cavity) may be selected as to obtain melt-extruded guides with the desired geometrical features [25][26] according to the application, i.e. the type of lesion (trauma extension and its localization in the body).…”

Section: Scanning Electron Microscopy Analysismentioning

confidence: 99%

Enzymatically‐Modified Melt‐Extruded Guides for Peripheral Nerve Repair

Chiono¹,

Ciardelli²,

Vozzi³

et al. 2008

Engineering in Life Sciences

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In this work, melt-extruded guides for peripheral nerve repair were produced, based on blends between poly-(e-caprolactone) and gelatin with a low gelatin amount (10 wt. %), with the aim of combining the good melt process ability of the synthetic polymer with the optimal biocompatibility of the natural polymer. In one case, a blend was produced between poly-(e-caprolactone) and gelatin previously crosslinked by transglutaminase, using a solution mixing technique. The blend was then melt-extruded obtaining nerve guidance channels. In another case, a blend between poly-(e-caprolactone) and uncrosslinked gelatin was first produced, then melt-extruded into tube-shaped manufacts. Finally, poly-L-lysine was grafted on the gelatin domains exposed on the inner tube surface using transglutaminase catalysis, with the aim to confer to the channel guide a specific signaling for nerve cells attachment, proliferation and migration. Scanning electron microscopy (SEM) and Fourier transform infrared-attenuated total reflectance spectroscopy (FTIR-ATR) coupled with Chemical Imaging analysis showed that the obtained binary blends were poor compatible, however, appropriate mixing techniques might lead to an homogeneous distribution of gelatin domains within the poly-(e-caprolactone) matrix. Confocal microscopy (CM) was applied as a powerful tool to study the accessibility of mTGase towards gelatin substrates, using suitable model lysine-rich peptides (FITC-labeled KKKKGY). Confocal microscopy also gave a confirmation of poly-L-lysine enzymatic grafting on the exposed gelatin domains on the inner blend tube surface. In vitro cell tests using S5Y5 neuroblastoma cells showed that the produced nerve guides were biocompatible, however, gelatin was confirmed to be a non-specific protein for the attachment and proliferation of nerve cells. On the other hand, poly-L-lysine functionalization of the inner tube surface greatly improved the in-vitro cell response.

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Melt‐spun hollow fibers: Modeling and experiments

Cited by 27 publications

References 14 publications

Melt-extruded guides for peripheral nerve regeneration. Part I: Poly(ε-caprolactone)

Melt-extruded guides for peripheral nerve regeneration. Part I: Poly(ε-caprolactone)

Flow Perfusion Improves Seeding of Tissue Engineering Scaffolds with Different Architectures

Enzymatically‐Modified Melt‐Extruded Guides for Peripheral Nerve Repair

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