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1
Choy, Wai-man, and 蔡維敏. "Flexible nerve guidance conduit for peripheral nerve regeneration." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B47326621.
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The golden method of peripheral nerve system injury is the nerve autograft, but it is associated with
drawbacks such as donor site morbidity, needs of second incisions and the shortage of nerve grafts.
Comparatively, connecting the nerve defect directly is an alternative. Unfortunately, if the defects
are long, the induced tension will deteriorate the nerve regeneration. These limitations led to the
development of artificial nerve guidance conduit (NGC). The market available NGC have problems
of unsatisfactory functional recovery and may collapse after the implantation. These are attributed
to material and structural deficiencies. Therefore, there is essential to study a biomaterial, which has
excellent biological and physical properties to fit the NGC application. In addition, some studies
suggested that the poor functional recovery resulted from the NGC implantation were due to the
lack of micro-guidance inside the conduit. Thus, it is necessary to investigate the structural
influence on the functional recovery of peripheral nerve injury.
Crosslinked urethane-doped polyester elastomer (CUPE) is newly invented for a blood vessel graft
because it possesses similar mechanical properties of blood vessel which is similar to nerve as well.
Therefore, CUPE was also considered to be the NGC. Its biocompatibility has been proved to be
excellent in the previous study done by Dr. Andrew SL, Ip. Targeting on the long peripheral nerve
regeneration, the aims of this study are (1) to investigate the biocompatibility of CUPE in in-vitro
condition and (2) to study the influence of nerve-like structure on the peripheral nerve system injury
in an animal model. The ultimate goal is to enhance the functional recovery of peripheral nerve
system injury by implanting a flexible biomaterial, CUPE, which has a nerve-like microarchitecture.
It is hypothesized that the nerve-like structure can promote the axonal regeneration.
The surface energy and roughness of CUPE were investigated. It showed a relatively low surface
energy compared to other conventional biopolymers such that the cell adhesion and also the
proliferation were inhibited. Therefore, the CUPE was modified by the immersion into a high
glucose DMEM. The change in the hydrophilicity, roughness and cell viability of medium treated
CUPE were studied. The hydrophilicity of treated CUPE was increased but the roughness was
remaining unchanged whereas the pH of the immersion solution did not cause any effect on the cell
activity on the CUPE. In the pilot animal study, five channels along the CUPE-NGC had a similar
myelinated fiber density and population compared to the nerve autograft. Also, the channels in the
CUPE-NGC were fragmented.
In summary, the medium treatment could enhance the hydrophilicity of CUPE and the cell activity
on CUPE. Such modifications did not governed by the pH of the medium. The NGC-CUPE with
five channels, which imitated a basic nerve structure was shown to have a similar tissue
regeneration and the functional recovery as the nerve autograft did. The results proved the
hypothesis that the nerve-like structure can promote the functional recovery of peripheral nerve
system injury with the use of a new biomaterial, CUPE as the NGC substrate.published_or_final_version
Orthopaedics and Traumatology
Master
Master of Philosophy
2
Mobasseri, Seyedeh. "Design and development of a nerve guide conduit with novel structural properties for peripheral nerve repair." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/design-and-development-of-a-nerve-guide-conduit-with-novel-structural-properties-for-peripheral-nerve-repair(b7e551b7-80c1-4f65-aaef-955a58623be8).html.
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The present study has developed poly ε-caprolactone (PCL)/ poly lactic acid (PLA) films with specific internal structure suitable to prepare nerve guide conduit for peripheral nerve repair. The film preparation method has been carried out using an environmental chamber to prepare the solvent cast films with the specific surface structure. Different cellular behaviour of neuronal cell cultures was seen on the pitted films with different pits configurations (size and distribution). The consistent surface morphology provided a reliable surface structure for further in vitro and in vivo studies. The effect of a medical grade sterilisation process using gamma radiation at eight doses (0-45kGy) on PCL/PLA films was explored. It has been shown that material properties, including mechanical strength, were significantly affected, while cellular behaviour and responses (NG108-15) were improved. Grooved films with three groove shapes (Sloped, Square, and V shape) were prepared using patterned silicon substrates, photolithography and wet/dry etching. The groove patterns were successfully transferred and good mechanical strength was observed for grooved PCL/ PLA. Oriented growth of NG108-15 cells was observed on the patterned films with an improved alignment and organisation on SL and V shape grooved films. UV-ozone treatment was used to increase hydrophilicity of PCL/PLA films to improve Schwann cells behaviour. No negative effect was observed on cell growth and proliferation on the treated films however the mechanical properties were reduced. Schwann cells expressed typical long spindle-shape morphology with cell-to-cell interaction in longitudinal direction on the treated grooved films. Consistent to in vitro experiment with NG108-15, Schwann cells alignment was also improved on SL and V shape grooves. A three-week in vivo study was carried out to test grooved and non-grooved conduits in a rat sciatic nerve model. The grooved conduits showed better regeneration, with SL-grooved film showing a significant improvement of nerve regeneration. A separate in vivo study evaluated the effect of wall-thickness on nerve regeneration. However, it was shown that the wall thickness had no positive effect, and the conduit with improved mechanical strength adversely affected the nerve regeneration. In conclusion, a nerve guide conduit was developed with the optimised surface structure to support nerve regeneration. The promising in vitro and in vivo studies together with the suitable biomechanical properties and specific surface structure and morphology indicate that the grooved PCL/PLA conduit is a viable treatment for peripheral nerve repair.
3
Martin, Christopher. "Development of a bioelectric nerve conduit using solenoid technology, and nano fabrication." Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/5278/.
Full textAbstract:
Peripheral nerve repair outcomes have lagged behind comparable surgical techniques for many decades. A number of advanced approaches have been adopted over the last ten years. In particular the application of electrical stimulation during a repair is of great interest. It is clear that electrical stimulation of regenerating nerve tissue has a great many effects and can improve functional outcomes for patients. This work has focused on developing systems capable of applying accurate electric fields on the microscale within a biodegradable conduit, powered wirelessly. Experiments were conducted in vitro with a view to making progress towards an in vivo implementation. Electrical stimulation was applied to regenerating sensory neurons in vitro, from a rat dorsal root ganglion. Mechanical guidance cues aligned neurons towards different microelectrode configurations in order to record the effect of applied electrical stimulation. This was performed using custom stimulation modules. SU-8 microgrooves and Ti/Au electrodes acted as mechanical and electrical cues respectively. This method was employed to great effect, identifying the effect of a number of electrical stimulation parameters. This led to a stimulation protocol featuring a 1:4 duty cycle, 20 mV amplitude, 100 Hz sinusoidal signal. This produced a number of interesting effects, including neuronal turning and a barrier formation. These results, demonstrated at the cellular level using a custom device and an autonomous stimulation system illustrates progress towards an optimised electrical stimulation waveform for neuronal growth control. A novel transfer printing process was developed to produce patterned gold films on the biodegradable polymer, polycaprolactone. Patterned Au, 400 nm thick, was transferred to a sheet of the polymer, producing a 15 turn, spiral inductor. The inductor was then electroplated to a thickness of 30 μm and wire-bonded. Power and data were transferred wirelessly to the receiver circuit. Receiver circuits, connected to stimulation test modules in planar form, delivered electrical stimulation waveforms to regenerating sensory neurons on polycaprolactone. This stimulation resulted in confinement of the cells between two pairs of electrodes, demonstrating the efficacy of the novel receiver circuits. This was achieved with four electrodes in a twin-barrier configuration. These results illustrate progress towards implantation in vivo, using remotely powered electronics to guide regenerating neurons to their targets with microelectrodes. Sensing cell growth through changes in electrical impedance is a well-documented technique. A receiver inductor has been connected to caco-2 cells in culture. Power was transmitted to the receiver inductor through an inductive link. Changes in the cell-monolayer have been detected at the transmitter output circuit, showing that the impedance changes are of sufficient magnitude to be reflected to the transmitter. Trypsin or EDTA were added to confluent layers of caco-2 cells, detaching them from the surface of the microchannel electrode array. This detachment was seen at the transmitter in the form of transient voltage changes. Data was acquired in using Labview programming and PXI hardware systems. This work illustrates progress towards biodegradable, passive cell sensing inspired by radio frequency identification technology, and electric cell impedance sensing.
4
Hazari, Anita. "Synthetic conduits and growth factors for improved peripheral nerve regeneration." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391620.
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5
McGrath, Aleksandra. "Development of biosynthetic conduits for peripheral nerve repair." Doctoral thesis, Umeå universitet, Anatomi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-60915.
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Peripheral nerve injuries are often associated with significant loss of nervous tissue leading to poor restoration of function following repair of injured nerves. Although the injury gap could be bridged by autologous nerve graft, the limited access to donor material and additional morbidity such as loss of sensation and scarring have prompted a search for biosynthetic nerve transplants. The present thesis investigates the effects of a synthetic matrix BD™ PuraMatrix™ peptide (BD)hydrogel, alginate/fibronectin gel and fibrin glue combined with cultured rat Schwann cells or human bone marrow derived mesenchymal stem cells (MSC) on neuronal regeneration and muscle recovery after peripheral nerve injury in adult rats. In a sciatic nerve injury model, after 3 weeks postoperatively, the regenerating axons grew significantly longer distances within the conduits filled with BD hydrogel if compared with the alginate/fibronectin gel. The addition of rat Schwann cells to the BD hydrogel drastically increased regeneration distance with axons crossing the injury gap and entering into the distal nerve stump. However, at 16 weeks the number of regenerating spinal motoneurons was decreased to 49% and 31% in the BD hydrogel and alginate/fibronectin groups respectively. The recovery of the gastrocnemius muscle was also inferior in both experimental groups if compared with the nerve graft. The addition of the cultured Schwann cells did not further improve the regeneration of motoneurons and muscle recovery. The growth-promoting effects of the tubular conduits prepared from fibrin glue were also studied following repair of short and long peripheral nerve gaps. Retrograde neuronal labeling demonstrated that fibrin glue conduit promoted regeneration of 60% of injured sensory neurons and 52% of motoneurons when compared with the autologous nerve graft. The total number of myelinated axons in the distal nerve stump in the fibrin conduit group reached 86% of the nerve graft control and the weight of gastrocnemius and soleus muscles recovered to 82% and 89%, respectively. When a fibrin conduit was used to bridge a 20 mm sciatic nerve gap, the weight of gastrocnemius muscle reached only 43% of the nerve graft control. The morphology of the muscle showed a more atrophic appearance and the mean area and diameter of fast type fibres were significantly worse than those of the corresponding 10 mm gap group. In contrast, both gap sizes treated with nerve graft showed similar fiber size. The combination of fibrin conduit with human MSC and daily injections of cyclosporine A enhanced the distance of regeneration by four fold and the area occupied by regenerating axons by three fold at 3 weeks after nerve injury and repair. In addition, the treatment also significantly reduced the ED1 macrophage reaction. At 12 weeks after nerve injury the treatment with cyclosporine A alone or cyclosporine A combined with hMSC induced recovery of the muscle weight and the size of fast type fibres to the control levels of the nerve graft group. In summary, these results show that a BD hydrogel supplemented with rat Schwann cells can support the initial phase of neuronal regeneration across the conduit. The data also demonstrate an advantage of tubular fibrin conduits combined with human MSC to promote axonal regeneration and muscle recovery after peripheral nerve injury.
6
Goodman, Bryce. "Commercialization of Epineural Conduits for Enhancement of Nerve Regeneration in Segmental Nerve Defects." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1340649008.
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7
Pettersson, Jonas. "Biosynthetic conduits and cell transplantation for neural repair." Doctoral thesis, Umeå universitet, Institutionen för integrativ medicinsk biologi (IMB), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-42440.
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Spinal cord injury results in complete failure of the central neurons to regenerate and is associated with cyst formation and enlargement of the trauma zone. In contrast to the spinal cord, axons in the injured peripheral nerve have the capacity to undergo some spontaneous regeneration. However, significant post-traumatic loss of nervous tissue causing long nerve gap is one of the main reasons for the poor restoration of function following microsurgical repair of injured nerves. The present thesis investigates the effects of biodegradable conduits prepared from fibrin glue and poly-beta-hydroxybutyrate (PHB) in combination with cultured Schwann cells, mesenchymal stem cells and extracellular matrix molecules on regeneration after spinal cord and peripheral nerve injury in adult rats. At 4-8 weeks after transplantation into the injured spinal cord, the PHB conduit was well integrated into the cavity but regenerating axons were found mainly outside the PHB. When suspension of BrdU-labeled Schwann cells was added to the PHB, regenerating axons filled the conduit and became associated with the implanted cells. Modification of the PHB surface with extracellular matrix molecules significantly increased Schwann cell attachment and proliferation but did not alter axonal regeneration. To improve the labeling technique of the transplanted cells, the efficacy of fluorescent cell tracers Fast Blue, PKH26, Vibrant DiO and Cell Tracker™ Green CMFDA was evaluated. All tested dyes produced very efficient initial labeling of olfactory ensheathing glial cells in culture. The number of Fast Blue-labeled cells remained largely unchanged during the first 4 weeks whereas the number of cells labeled with other tracers was significantly reduced after 2 weeks. After transplantation into the spinal cord, Fast Blue-labeled glial cells survived for 8 weeks but demonstrated very limited migration from the injection sites. Additional immunostaining with glial and neuronal markers demonstrated transfer of the dye from the transplanted cells to the host tissue. In a sciatic nerve injury model, the extent of axonal regeneration through a 10mm gap bridged with tubular PHB conduit was compared with a fibrin glue conduit. At 2 weeks after injury, the fibrin conduit supported similar axonal regeneration and migration of the host Schwann cells compared with the PHB conduit augmented with a diluted fibrin matrix and GFP-labeled Schwann cells or mesenchymal stem cells. The long-term regenerative response was evaluated using retrograde neuronal labeling. The fibrin glue conduit promoted regeneration of 60% of sensory neurons and 52% of motoneurons when compared with the autologous nerve graft. The total number of myelinated axons in the distal nerve stump in the fibrin conduit group reached 86% of the nerve graft control and the weight of gastrocnemius and soleus muscles recovered to 82% and 89%, respectively. When a fibrin conduit was used to bridge a 20mm sciatic nerve gap, the weight of gastrocnemius muscle reached only 43% of the nerve graft control. The morphology of the muscle showed more chaotic appearance and the mean area and diameter of fast type fibers were significantly worse than those of the corresponding 10mm gap group. In contrast, both gap sizes treated with nerve graft showed similar fiber size. In summary, these results show that a PHB conduit promotes attachment, proliferation and survival of adult Schwann cells and supports marked axonal growth after transplantation into the injured spinal cord. The data suggest an advantage of the fibrin conduit for the important initial phase of peripheral nerve regeneration and demonstrate potential of the conduit to promote long-term neuronal regeneration and muscle recovery.
8
Kalbermatten, Daniel. "Nerve gap repair by the use of artificial conduits and cultured cells." Doctoral thesis, Umeå universitet, Anatomi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-35582.
Full textAbstract:
Peripheral nerve injuries are often associated with loss of nerve tissue and require autologous nerve grafts to provide a physical substrate for axonal growth. This thesis investigates the use of fibrin as both a tubular conduit to guide nerve regeneration and also as a matrix material to suspend various regenerative cell types within/on poly-3-hydroxybutyrate (PHB) nerve conduits. Adipose derived stem cells (ASC) are found in abundant quantities. In this thesis the ability of rat ASC to differentiate into Schwann cells was determined and a preliminary study of the neurotrophic potential of human ASC was also investigated. Rat sciatic nerve axotomy was performed proximally in the thigh to create a 10-mm gap between the nerve stumps and the gap was bridged using the various conduits. At early time points the nerve grafts were harvested and investigated for axonal and Schwann cell markers. After 16 weeks the regenerative response from sensory and motor neurons was also evaluated following retrograde labelling with Fast Blue fluorescent tracer. Stem cells were treated with a mixture of glial growth factors and after 2 weeks in vitro the expression of Schwann cell markers was analysed by immunocytochemistry and Western blotting. ASC were cocultured with the NG108-15 neuronal cell line to determine their ability to promote neurite outgrowth. Human ASC were isolated from the deep and superficial layers of abdominal fat tissue obtained during abdominoplasty procedures. RT-PCR was used to investigate the expression of neurotrophic factors. Immunohistochemistry showed a superior nerve regeneration distance in the fibrin conduit compared with PHB. The fibrin conduit promoted regeneration of 60% of sensory neurones and 52% of motor neurones when compared with an autograft group at 16 weeks. The total number of myelinated axons in the distal nerve stump in the fibrin-conduit group reached 86% of the graft and the weight of gastrocnemius and soleus muscles recovered to 82% and 89% of the controls, respectively. In vitro studies showed that rat ASC could be differentiated to a Schwann cell phenotype. These treated cells enhanced both the number of NG108-15 cells expressing neurites and neurite length. In the same coculture model system, human superficial fat layer ASC induced significantly enhanced neurite outgrowth when compared with the deep layer fat cells. RT-PCR analysis showed ASC isolated from both layers expressed neurotrophic factors. These results indicate that a tubular fibrin conduit can be used to promote neuronal regeneration following peripheral nerve injury. There was also a beneficial effect of using a fibrin matrix to seed cells within/on PHB conduits which should ultimately lead to improved functional recovery following nerve injury. There might also be an advantage to use a simple strip of PHB rather than a conventional tube-like structure implying that single fascicle nerve grafting could be advantageous for nerve repair. The results of in vitro experiments indicate adipose tissue contains a pool of regenerative stem cells which can be differentiated to a Schwann cell phenotype and given that human ASC express a range of neurotrophic factors they are likely to be of clinical benefit for treatment of peripheral nerve injuries.
9
Yurie, Hirofumi. "The efficacy of a scaffold-free Bio 3D conduit developed from human fibroblasts on peripheral nerve regeneration in a rat sciatic nerve model." Kyoto University, 2019. http://hdl.handle.net/2433/242407.
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10
An, Xiaoxian. "Magnesium metal implants and their effects on soft tissue repairs." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1592395032696939.
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11
Yip, Siu-leung, and 葉紹亮. "Biocompatibility and efficacy of a new synthetic polymer, crosslinked urethane-doped polyester elastomers (CUPEs), as nerve conduit forreconstruction of segmental peripheral nerve defect using rat model." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45153759.
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Ho, Wing-hang Angela, and 何穎恆. "Biocompatibility and efficacy of five-channel and eight-channel crosslinked urethane-doped polyester elastomers (CUPEs) as nerve guidance conduit for reconstruction of segmental peripheral nerve defect using rat model." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/193523.
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Introduction
Peripheral nerve injury is common in clinical practice. The usual etiologies are penetrating injury, stretch, compression, crush and ischemia. Outcome of nerve injury depends on the etiology and also the management. Nerve defect is a challenging scenario. The current gold standard of managing a nerve defect is autologous nerve graft.
However, due to the selection of nerve graft and donor site morbidity, artificial nerve conduits are gaining popularity. However, there are drawbacks of single hollow conduit such as lack of internal support to prevent conduit collapse and inability so as to recreate the proper native spatial arrangement of cells and extracellular matrix within the conduit. In this study, the biocompatibility and efficacy of five-channel and eight-channel Crosslinked Urethane-doped Polyester Elastomers (CUPEs) as nerve guidance conduit will be evaluated through a rat model with reconstruction of segmental peripheral nerve defect.
Material and method
Eighteen adult Sprague-Dawley rats were used. Tthey were randomly allocated to three groups: autograft group, five-channel conduit group and eight-channel conduit group with each consisted of six rats. A 10mm nerve defects were created at the right sciatic nerve. They were bridged with reverse autograft, 5-channel conduit and 8-channel conduit. After eight weeks the rats were euthanized and the reconstructed nerves were harvested for histomorphometric analysis.
Results
All conduits showed regenerated nerve tissue inside. There was no collapse of the conduits. There were no severe tissue reaction or scarring near the reconstructed nerve. No neuroma was formed. Histomorphometric analysis showed nerve regeneration was enhanced with increasing number of channels inside conduit. There was overall drop in fiber density between proximal and distal segment among all groups.
Conclusions
CUPE nerve guidance conduit is biocompatible and shows good nerve regeneration in reconstructing nerve defect.published_or_final_version
Obstetrics and Gynaecology
Master
Master of Medical Sciences
13
Silantyeva, Elena A. "Functionalized Nanofiber Substrates for Nerve Regeneration." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1555582661302756.
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Vennemeyer, John J. "Investigation of Magnesium-based Interventions for Central and Peripheral Nervous Tissue Regeneration." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367940294.
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Mitsuzawa, Sadaki. "The Efficacy of a Scaffold-free Bio 3D Conduit Developed from Autologous Dermal Fibroblasts on Peripheral Nerve Regeneration in a Canine Ulnar Nerve Injury Model: A Preclinical Proof-of-Concept Study." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263517.
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Thomson, Suzanne Emma. "Translational development of a three-dimensional bioactive conduit for peripheral nerve repair, through the application of topographical cues & stem cell support." Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/8747/.
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Arslantunali, Damla. "Multiwalled Carbon Nanotube- Poly(2-hydroxyethyl Methacrylate) Composite Conduitfor Peripheral Nerve Repair." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614105/index.pdf.
Full textAbstract:
There are different methods used in the surgical treatment of peripheral nerve injury. In this respect, end-to-end surgical reconnection of the damaged nerve ends or autologous nerve grafts are applied as soon as possible after the injury. When autologous tissue transplant is considered, there are some medical devices available generally for relatively short nerve defects. As a solution for this problem, different tissue engineered nerve conduits have been developed.
In the current study, a pHEMA hydrogel membranes were designed to mimic the tubular conduits and they were loaded with 1-6% (w/w) multiwalled carbon nanotubes (mwCNTs) to obtain electrical conductivity. The most important reason for the use of CNTs in peripheral nerve injury is their electrical conductivity. Within the context of the study, the degree of swelling, contact angles, electrical conductivity and mechanical properties of the membranes were analyzed. As the amount of mwCNTs were increased, the contact angles, indicating higher hydrophobicity and the electrical conductivity increased. The tensile test of the mwCNT-pHEMA composite membranes showed that the membranes have viscoelastic structure similar to the structure of the soft tissues. The structure of the mwCNT containing pHEMA composite membranes were analyzed with different microscopical techniques such as SEM, CSLM and microCT. MwCNTs on the hydrogels were morphologically similar to the original. SEM micrographs also showed that the mwCNTs were grouped in clumps on hydrogel surfaces. No mwCNT leaching was observed because the mwCNTs were embedded in the hydrogel, therefore, no cytotoxic effect was observed. The pHEMA hydrogels were porous which is suitable for transportation of materials, electrolytes and gas needed for cell nutrition and growth.
In the in vitro studies, SHSY5Y neuroblastoma cells were seeded on the membranes to determine the sustainability and effects of the membranes on the cell growth. Electrical potential of 1 and 2 V were used to stimulate the cells. Microscopical examination with SEM and CSLM, and MTT viability assay were used. The SHSY5Y neuroblastoma cells were attached and proliferated on both the composite and the hydrogel membranes. The cells on pHEMA membranes without mwCNTs, however, were not able to survive after application of electrical potential.
As a conclusion, use of composite membranes in the treatment of peripheral nerve injury as a nerve conduit is appropriate. Electrical stimulation, however, did not induce the cells to align in contrast to the expected results, indicating potential and current application regime needs to be optimized to obtain the desired results.
18
McKay, Hart Andrew. "Sensory neuronal protection & improving regeneration after peripheral nerve injury." Doctoral thesis, Umeå universitet, Handkirurgi, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-52.
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Peripheral nerve trauma is a common cause of considerable functional morbidity, and healthcare expenditure. Particularly in the ~15% of injuries unsuitable for primary repair, standard clinical management results in inadequate sensory restitution in the majority of cases, despite the rigorous application of complex microsurgical techniques. This can largely be explained by the failure of surgical management to adequately address the neurobiological hurdles to optimal regeneration. Most significant of these is the extensive sensory neuronal death that follows injury, and which is accompanied by a reduction in the regenerative potential of axotomised neurons, and in the supportive capacity of the Schwann cell population if nerve repair is delayed. The present study aimed to accurately delineate the timecourse of neuronal death, in order to identify a therapeutic window during which clinically applicable neuroprotective strategies might be adopted. It then proceeded to investigate means to increase the regenerative capacity of chronically axotomised neurons, and to augment the Schwann cells’ ability to promote that regenerative effort. Unilateral sciatic nerve transection in the rat was the model used, initially assessing neuronal death within the L4&5 dorsal root ganglia by a combination of morphology, TdT uptake nick-end labelling (TUNEL), and statistically unbiased estimation of neuronal loss using the stereological optical disector technique. Having identified 2 weeks, and 2 months post-axotomy as the most biologically relevant timepoints to study, the effect upon neuronal death of systemic treatment with acetyl-L-carnitine (ALCAR 10, or 50mg/kg/day) or N-acetyl-cysteine (NAC 30, or 150mg/kg/day) was determined. A model of secondary nerve repair was then adopted; either 2 or 4 months after unilateral sciatic nerve division, 1cm gap repairs were performed using either reversed isografts, or poly-3-hydroxybutyrate (PHB) conduits containing an alginate-fibronectin hydrogel. Six weeks later nerve regeneration and the Schwann cell population were quantified by digital image analysis of frozen section immunohistochemistry. Sensory neuronal death begins within 24 hours of injury, but takes 1 week to translate into significant neuronal loss. The rate of neuronal death peaks 2 weeks after injury, and neuronal loss is essentially complete by 2 months post-axotomy. Nerve repair is incompletely neuroprotective, but the earlier it is performed the greater the benefit. Two clinically safe pharmaceutical agents, ALCAR & NAC, were found to virtually eliminate sensory neuronal death after peripheral nerve transection. ALCAR also enhanced nerve regeneration independently of its neuroprotective role. Plain PHB conduits were found to be technically simple to use, and supported some regeneration, but were not adequate in themselves. Leukaemia inhibitory factor enhanced nerve regeneration, though cultured autologous Schwann cells (SC’s) were somewhat more effective. Both were relatively more efficacious after a 4 month delay in nerve repair. The most profuse regeneration was found with recombinant glial growth factor (rhGGF-2) in repairs performed 2 months after axotomy, with results that were arguably better than were obtained with nerve grafts. A similar conclusion can be drawn from the result found using both rhGGF-2 and SC’s in PHB conduits 4 months after axotomy. In summary, these findings reinforce the significance of sensory neuronal death in peripheral nerve trauma, and the possibility of its` limitation by early nerve repair. Two agents for the adjuvant therapy of such injuries were identified, that can virtually eliminate neuronal death, and enhance regeneration. Elements in the creation of a bioartificial nerve conduit to replace, or surpass autologous nerve graft for secondary nerve repair are presented.
19
Asada, Yoshiyuki. "Neural repair of the injured spinal cord by grafting : comparison between peripheral nerve segments and embryonic homologous structures as a conduit of CNS axons." Kyoto University, 2002. http://hdl.handle.net/2433/149743.
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Mohanna, Pari-Naz. "Bioengineeringof nerve conduits." Thesis, University College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.406160.
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Mokarram-Dorri, Nassir. "Modulating immune response inside biomaterial-based nerve conduits to stimulate endogenous peripheral nerve regeneration." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54860.
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Injuries to the peripheral nervous system (PNS) are major and common source of disability, impairing the ability to move muscles and/or feel normal sensations, or resulting in painful neuropathies. Annually traumatic nerve injuries resulting from collisions, gunshot wounds, fractures, motor vehicle accidents, lacerations, and other forms of penetrating trauma, affected more than 250,000 patients just in the U.S. The clinical gold standard to bridge long non-healing nerve gaps is to use a nerve autograft- typically the patient’s own sural nerve. However, autografts are not ideal because of the need for secondary surgery to ‘source’ the nerve, loss of function at the donor site, lack of appropriate source nerve in diabetic patients, neuroma formation, and the need for multiple graft segments. Despite our best efforts, finding alternative ‘nerve bridges’ for peripheral nerve repair remains challenging – of the four nerve ‘tubes’ FDA approved for use in the clinic, none is typically used to bridge gaps longer than 10 mm due to poor outcomes. Hence, there is a compelling need to design alternatives that match or exceed the performance of autografts across critically sized nerve gaps.
Here we demonstrate that early modulation of innate immune response at the site of peripheral nerve injury inside biomaterials-based conduit can favorably bias the endogenous regenerative potential after injury that obviates the need for the downstream modulation of multiple factors and has significant implications for the treatment of long peripheral nerve gaps. Moreover, our study strongly suggests that more than the extent of macrophage presence, their specific phenotype at the site of injury influence the regenerative outcomes. This research will advance our knowledge regarding peripheral nerve regeneration, and help developing technologies that are likely to improve clinical outcomes after peripheral nerve injury. The significant results presented here are complementary to a growing body of evidence showing the direct correlation between macrophage phenotype and the regeneration outcome of injured tissues.
22
Tohill, Mel Patrick. "Cellular and gene therapies for the enhancement of peripheral nerve regeneration through bio-engineered nerve conduits." Thesis, University College London (University of London), 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497805.
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Sedaghati, T. "Design and development of nerve conduits for peripheral nerve regeneration using a new bioabsorbable nanocomposite polymer." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1465974/.
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Nerve autografting is the “gold standard” technique to repair nerve defects with a gap larger than 30 mm. The current commercially available FDA and CE approved nerve conduits offer considerable benefits to the patients suffering from completely transected nerve. They fail, however, to support neural regeneration in gaps over 30 mm. The aim of this research was to design, develop and evaluate new nerve conduits made from a biodegradable nanocomposite material known as polyhedral oligomeric silsesquioxanes incorporated poly (caprolactone) urea/ urethane (POSS-PCL). This material has been previously shown to have favourable cellular interactions. The biomechanical properties of POSS-PCL nanocomposite with varying POSS concentration were evaluated. Increasing POSS concentration resulted in less viscous polymer solution while increased the surface hydrophobicity, surface roughness and in vitro protein absorption. This increase, however, caused a considerable reduction in Schwann cells proliferation and rounded morphology. To enhance cellular interactions of the POSS-PCL surface, it was functionalized with synthetic RGD peptide, which resulted in an increase of SCs average process length while reducing the hydrophobicity of POSS-PCL surface. Furthermore, human adipose derived stem cells were successfully differentiated into Schwann-like cells as determined by S-100 expression and NGF production. The porogen concentration used for making porous conduits was also investigated using solvent evaporation technique combined with porogen leaching. It was demonstrated that 2% POSS-PCL with 30% porogen had the favourable viscoelastic properties for nerve conduit manufacturing. Two types of nerve conduit with varying wall thicknesses were fabricated and examined for their physiochemical properties. Double layered conduits were considered more suitable for the short-term pilot in vivo study as they had higher compressive resistance and suture retention ability than the single layered ones. Following in vivo implantation of conduits, Visual observations showed good interaction of conduits with surrounding tissue and no obvious inflammation at the repair site after 6 weeks. Histology revealed that the porous conduit (17.53±6.44 μm pore size) improved myelin sheath formation compared to non-porous POSS-PCL nerve conduit. Further investigations of POSS-PCL conduits are required to determine if this implant can overcome the limitation of commercially available nerve conduits.
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Longo, Marco Vinicius Losso. "Influência da adição de células-tronco mesenquimais derivadas de tecido adiposo associadas a conduto de fibrina na regeneração de nervo periférico em modelo experimental de ratos." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/5/5132/tde-21012016-164659/.
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INTRODUÇÃO: O tratamento padrão para lesões de nervo periférico que não podem ser suturados primariamente é a enxertia de nervo autólogo. Esse método, porém, carece de resultados satisfatórios e impõe algumas limitações técnicas e complicações. Várias opções já foram estudadas como alternativas ao enxerto de nervo, porém ainda não há conduto biológico ou sintético disponível para uso clínico que tenha a mesma capacidade regenerativa do enxerto de nervo autólogo. Os avanços em cultura celular e o maior entendimento dos mecanismos moleculares e celulares da regeneração nervosa levaram ao uso de células promotoras de regeneração associado aos condutos na tentativa de melhorar os resultados da reconstrução nervosa. Vários estudos demonstraram que o uso de célulastronco derivadas de tecido adiposo (ADSC) em condutos aloplásticos potencializa a regeneração neural. No entanto, nenhum estudo até hoje comparou a adição de ADSC indiferenciadas em conduto aloplástico ao tratamento padrão com autoenxerto. Esse estudo tem como objetivo avaliar a influência da adição de células-tronco mesenquimais derivadas de tecido adiposo em conduto de fibrina na regeneração de nervo periférico e comparar com enxertia de nervo autógeno em modelo experimental de ratos. MÉTODO: Em um modelo de lesão de nervo ciático (defeito de 10 mm) foram avaliados 30 ratos Wistar divididos em 3 grupos. O defeito de nervo foi reconstruído usando conduto de fibrina (Grupo Conduto, n=10), conduto de fibrina acrescido de ADSC (Grupo ADSC, n=10) e autoenxerto do nervo (Grupo Autoenxerto, n=10). A avaliação funcional dos ratos foi realizada com o teste de marcha (walking track analysis) com 4, 8 e 12 semanas e o índice de função ciática (IFC) foi determinado. Após 12 semanas, o peso do músculo tríceps sural foi avaliado. Segmentos dos nervos regenerados também foram coletados para análises histológicas como densidade axonal e diâmetro médio das fibras. RESULTADOS: O grupo Conduto mostrou recuperação funcional no teste da marcha após a reconstrução do nervo, porém com resultados inferiores aos outros dois grupos. O grupo ADSC mostrou recuperação intermediária e o grupo Autoenxerto obteve os melhores resultados (IFC com 12 semanas de -53,3±.3 vs -44,7±3 vs - 35,6±2, respectivamente, p < 0,001). A relação de peso do músculo tríceps sural no grupo Conduto foi de 41,1±3%, no grupo ADSC de 53,3±4% e no grupo Autoenxerto de 71,0 ± 4% (p < 0,001). Na avaliação histológica, o grupo Conduto mostrou densidade axonal de 39,8±3 axônios/10.995?m2 e diâmetro médio das fibras de 3,9 ± 0?m2, o grupo ADSC densidade axonal de 58,8 ± 3 axônios/10.995um2 e diâmetro médio das fibras de 4,9 ± 1um2 e o grupo Autoenxerto densidade axonal de 67,1±2 axônios/10.995?m2 e diâmetro médio das fibras de 8,9±1um2 (p < 0,001). CONCLUSÃO: A adição de células-tronco mesenquimais derivadas de tecido adiposo (ADSC) em conduto de fibrina na regeneração de nervo periférico, em modelo experimental de ratos, mostrou recuperação funcional e regeneração histológica estatisticamente mais significativa comparada à reconstrução somente com conduto de fibrina, porém ainda aquém dos resultados obtidos com enxertia de nervo autógenoIntroduction: The standard treatment for peripheral nerve injuries that cannot be primarily sutured is nerve autograft. But this method lacks satisfactory results and imposes some technical limitations and complications. Several options have been studied as alternatives to nerve autografting, but there is no biological or synthetic conduit available for clinical use that provides the same regenerative capacity of nerve autograft. Advances in cell culture and understanding of nerve regeneration mechanisms led to the use of regeneration-inducing cells in association with conduits, in an attempt to improve the reconstruction results. Several studies have shown that the use of adipose derived stem cells (ADSC) into conduits enhances neural regeneration. However, there is no study that compared the addition of undifferentiated ADSC in alloplastic conduit to standard treatment with autograft. This study evaluated the influence of the addition of adipose derived stem cell in fibrin conduit for peripheral nerve regeneration in comparison to the nerve autograft, in a rat model. Method: A sciatic nerve injury model (10-mm defect) was performed in 30 Wistar rats, which were divided into 3 groups. Nerve defect was reconstructed using fibrin conduit (Conduit group, n=10), fibrin conduit filled with ADSC (ADSC group, n = 10) and nerve autograft, (Autograft group, n=10). The walking behavior was measured by footprint analysis at 4, 8, and 12 weeks and sciatic function index (SFI) was determined. After 12 weeks, the triceps surae muscle weight was evaluated and histological analysis was performed to evaluate the regenerated nerve and measured axonal density and fibers diameter average. Results: The Conduit group showed less improvement in walking behavior compared to ADSC group and Autograft group (SFI at 12 weeks, - 53.3 ± .3 vs -44.7 ± 3 vs -35.6 ± 2 respectively, p< 0.001). The triceps surae muscle weight ratio of the fibrin conduit group was 41.1± 3%, ADSC group was 53.3 ± 4%, and Autograft group 71.0 ± 4% (p < 0.001). In histological evaluation, the Conduit group showed axonal density of 39.8±3 axons/10995um2 and fiber diameter average of 3.9±0 ?m2, the ADSC group had axonal density of 58.8 ± 3 axons/10995 um2 and fiber diameter average of 4.9±1?m2 and axon density of Autograft group was 67.1±2 axons/10995 um2 and fiber diameter average was 8.9±1?m2 (p < 0.001). Conclusion: The addition of adipose derived stem cells (ADSC) into fibrin conduit used for nerve reconstruction following peripheral nerve injury in the rat model, showed better functional recovery and better histological regeneration compared to reconstruction with fibrin conduit without ADSC. However, the functional recovery in the ADSC group was worse than that in nerve Autograft group and the nerve repair with the ADSC-fibrin conduit has less myelinated fibers when compared to the repair with nerve autograf
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Meyer, Cora [Verfasser]. "Peripheral nerve regeneration using hollow and enriched chitosan-based guidance conduits / Cora Meyer." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2014. http://d-nb.info/1065262922/34.
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Taylor, Caroline. "Material selection for fabricating an internal guidance scaffold for improving current nerve guide conduits." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/22082/.
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Albadawi, Emad. "Neuroanatomical evaluation of the outcome of peripheral nerve repair using 3D printed biodegradable conduits." Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/20933/.
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Kaizawa, Yukitoshi. "BRIDGING A 30 MM DEFECT IN THE CANINE ULNAR NERVE USING VESSEL-CONTAINING CONDUITS WITH IMPLANTATION OF BONE MARROW STROMAL CELLS." Kyoto University, 2016. http://hdl.handle.net/2433/204575.
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Di, Summa Pietro Giovanni. "Schwann cell-like differentiated adipose-derived stem cells : in vivo applications and future perspectives for nerve regeneration." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/schwann-celllike-differentiatedadiposederived-stem-cellsin-vivo-applications-and-futureperspectives-for-nerve-regeneration(cce4ab09-f58b-48c6-9372-5efcb1127e1a).html.
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Traumatic injuries resulting in peripheral nerve lesions often require a graft to bridge the gap. Although autologous nerve graft is still the first choice strategy in reconstructions, it has the severe disadvantage of the sacrifice of a functional nerve. Cell transplantation in a bioartificial conduit is an alternative strategy to create a favourable environment for nerve regeneration. Among adult stem cells, adipose-derived stem cells (ASC) are a useful tool in regenerative medicine as they can be induced towards multiple mesodermal and nonmesodermal lineages, being recently differentiated into cells showing Schwann cell-like morphology, glial cell markers and increased neurotrophic potential. The first two chapters of this work describe in vivo applications of Schwann cell-like differentiated ASC (dASC), seeded into biodegradable nerve guides made of fibrin, investigating both brief (2 weeks) and long (4 months) term effects on the regenerating nerves. Comparison was carried out with similarly differentiated bone marrow mesenchymal stem cells (dMSC), Schwann cells (SC)and empty fibrin conduits, as well as with autologous nerve grafts. Regeneration was evaluated in a 1cm gap total axotomy sciatic nerve injury model on rats. Results showed that dASC could improve regeneration distance in a similar manner to other regenerative cells inthe brief term. This effect was maintained and strengthened in the long term, where nerve morphology, spinal motoneurons regeneration, protection from muscle atrophy and electrophysiological performances of regenerated nerves were analysed. dASC positive effects lasted in the long term with functional results comparable to the autologous nerve grafts, which served as controls. The third chapter focuses on the possibility to further improve dASC regenerative performances using fibronectin and laminin, two key extracellular matrix (ECM) molecules involved in nerve regeneration, with the future aim to optimize cell host, directional cues and neurotrophism of tissue engineered conduits. Fibronectin and laminin protected dASC from stress-induced cell death in vitro, significantly increasing cell adhesion and viability. Laminin significantly improved neurotrophic properties of dASC enhancing neurite outgrowth of both primary sensory neurons and NG108-15 neurons co-cultured with dASC, suggesting a further activation of the neurotrophic effect of dASC by ECM molecules. These improved effects were increased when a direct contact was established between the laminin substrate, dASC and neurons, suggesting a primary role of laminin in contact signalling, finally boosting the neurotrophic potential of dASC. Further studies will be needed to clarify the interactions between dASC and the complexniche of peripheral nerve regeneration, including the ECM molecules. However, the neurotrophic potential of dASC expressed in both in vitro and in vivo experiments opens wide perspectives in tissue engineering applications among new methods to enhance peripheral nerve repair.
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Toba, Toshinari. "Regeneration of canine peroneal nerve with the use of a polyglycolic acid-collagen tube filled with laminin-soaked collagen sponge : A comparative study of collagen sponge and collagen fibers as filling materials for nerve conduits." Kyoto University, 2003. http://hdl.handle.net/2433/148710.
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Ni, Hsiao-Chiang, and 倪孝強. "The application of nerve conduit in peripheral nerve reconstruction." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/27123790694954240063.
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博士國立中興大學
化學工程學系所
98
In the first part, an innovative technique combining phase transition and microprinting in one step was applied to fabricate the nerve conduits used in peripheral nerve regeneration. The asymmetric microporosity served to generate asymmetric permeability and the surface microgrooves were introduced to achieve cell alignment in vitro. The symmetric/asymmetric porous poly(D,L-lactide) (PLA) substrates with microgrooves on the surface were tested for their ability to repair 10 mm sciatic nerve transection defects in rats. The in vivo results showed that the regenerated nerves in the asymmetric conduits with surface microgrooves had highest degree of myelination at 4 weeks and the most number of vessels at 6 weeks. The walking track analysis also implied that the asymmetric conduits with surface microgrooves had the highest degree of functional recovery. To further improve the performance, chitosan (containing nano gold) and fibroblast growth factor 1 (FGF1) were sequentially grafted on the microgrooved PLA surface by the assistance of open air plasma treatment in the second part. Grafting of these components was verified with electron spectroscopy for chemical analysis (ESCA). The modified nerve conduits showed enhanced ability in the repair of 10 mm sciatic nerve transection defects in rats. In the third part, grafting of FGF1 was required to be performed on chitosan-nano Au modified surface for better activity of the released FGF1. The performance of the PLA conduits grafted by chitosan-nano Au and FGF1 also had the best result in the regeneration capacity and in promoting the functional recovery of sciatic nerve with large defect (15 mm) in rats. If the conduits were seeded with neural stem cells (NSCs), the degree of myelination and the area of regenerated nerve were further enhanced after 12 weeks. This was evident by the waveform of compound muscle action potentials which was relatively similar to that in autografts at 6 weeks, as well as the nerve conduction velocity which achieved about 90% of that in autografts at 12 weeks. Living NSCs were demonstrated in the regenerated nerve tissue after 6 weeks of implantation. Some NSCs had partially differentiated into glia-like cells. More NSCs were found in the regenerated nerve of the conduits if the nerve conduit employed had better performance prior to cell seeding. It is thus possible to consolidate tissue engineering nerve conduits with well-designed substrate, growth factors and stem cells that synergistically contribute to regenerate the severely damaged nerve.
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Hou-Yu, Chiang. "Efficacies of Nerve Regeneration after Grafting a Polycaprolactone Nerve Conduit." 2005. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-1207200517121800.
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Chiang, Hou-Yu, and 江皓郁. "Efficacies of Nerve Regeneration after Grafting a Polycaprolactone Nerve Conduit." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/04620325189816995588.
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博士國立臺灣大學
解剖學研究所
93
We established histopathological and neurophysiological approaches to examine whether different designs of polycaprolactone-engineered nerve conduits (hollow versus laminated), could promote nerve regeneration as autologous grafts after transection of sciatic nerves. Changes of various antigen profiles in Schwann cells and regenerated axons within the hollow and the laminated conduits were examined by immunohistochemistry. Nerve growth factor receptor (p75) and glial fibrillary acidic protein (GFAP) were up-regulated in the laminated conduit with fewer expressions of phosphorylated neurofilaments. Different results with down-regulations of p75 and GFAP and abundant expressions of phosphorylated neurofilaments were observed in the hollow conduit and the autologous graft. The findings revealed that the hollow conduit had better regeneration efficacy than the laminated one. For evaluating the long-term axonal regeneration and the functional recovery after conduit grafting, further quantitative assessments included morphometric analysis at the level of sciatic nerve, neuromuscular junction (NMJ) and gastrocnemius muscle, and nerve conduction studies on sciatic nerves were performed at POM 3 and POM 6. Six months after nerve grafting, the nerve fiber density in the hollow-conduit group was similar to that in the autologous-graft group; the laminated-conduit group only achieved ~20% of these values. The consequences of these differences were reflected in nerve growth into muscular targets; this was demonstrated by combined cholinesterase histochemistry for NMJ and immunohistochemistry for nerve fibers innervating NMJ with an axonal marker, protein gene product 9.5. Hollow conduits had similar index of NMJ innervation as autologous grafts; the values were higher than those of laminated conduits. Among the three groups, there were same patterns of differences in the cross-sectional area of muscle fibers and amplitudes of compound muscle action potential. These results indicate that hollow conduits were as efficient as autologous grafts to facilitate nerve regeneration, and provide a multidisciplinary approach to quantitatively evaluate muscular reinnervation after nerve injury.
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Chang, Shun-Hsung, and 張順雄. "Reinforcement of a Biodegradable Nerve Guide Conduit in Peripheral Nerve Repair." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/w4b6x2.
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碩士長榮大學
生物科技學系碩士班
98
This study developed a biodegradable reinforced nerve guide conduit (GGT), containing genipin cross-linked gelatin annexed with -tricalcium phosphate ceramic particles (TCP), was applied in peripheral nerve regeneration. The conduit was dark bluish in appearance and round with a rough and compact outer surface observed by SEM. Water uptake and swelling tests indicated that the conduit noticeably increased the stability in water, and the hydrated conduit did not collapse. From the in vitro degradation rate test, the degradation rates of the GGT conduits were attenuated as the weight ratios of the TCP was increased. The mechanical measurement showed that such good mechanical properties, which benefit from the addition of TCP ceramic particles, render it possible for the GGT conduit to resist the muscular contraction and keep its cylindrical shape unchanged within a considerable periods after implantation into the body. GGT-soaking solutions not only exhibited no toxicity but also promoted the viability, growth and GFAP expressions of adipose-derived stem cells (ADSCs). Moreover, the GGT composite film showed a better ability to support cell attachment and growth. Cytotoxicity tests revealed that the GGT conduit not only was not toxic but also promoted the viability and growth of neural stem cells (NSCs). Results of the in vitro cell culture test suggested that NSCs could attach onto the GGT conduit and the GGT-cell contact promoted the proliferation and differentiation of NSCs. This study cultured rat sciatic nerves on the GGT substrate to examine the in vitro biocompatibility of GGT conduits with peripheral nerve tissues. After 14 d of culture, more derived cells migrated out of the sciatic nerve and the neurites elongated from the neurons of sciatic nerve to form long cell chains under light microscopy. After 21 d of culture, many of the derived cells formed compact arrangements with a side-by-side or end-to-end configuration, forming a multi-layer structure covering the GGT substrate under SEM. Adding TCP ceramic particles reduced the degradation of GGT conduits by enzymes throughout the subcutaneous test and the rates of degradation in vivo decreased as the TCP content increased. After subcutaneous implantation on the dorsal side of a rat, the degraded conduit only evoked a mild tissue response, with the formation of a thin tissue capsule (< 100 μm) surrounding the conduit, indicating that the GGT conduits were biocompatible. Walking tract analysis showed a little higher SFI score and better improvement in the toe spreading in the GGT group than in the autograft group after eight weeks of implantation. Peak amplitude under the muscle action potential curve showed an increase as a function of the recovery period, indicating that the nerve had undergone adequate regeneration both in GGT and autograft group. These results demonstrate the feasibility of designed GGT conduits in the applications of peripheral nerve repair.
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Hsieh, Shu-Chih, and 謝淑枝. "Effect of an Epineurial-like Biohybrid Nerve Conduit on Nerve Regeneration." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/11503477024909257880.
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博士國立中興大學
化學工程學系所
104
A novel approach of making a biomimetic nerve conduit was established by seeding adipose-derived adult stem cells (ADSCs) on the external wall of porous poly(D, L-lactic acid) (PLA) nerve conduits. The PLA conduits were fabricated using gas foaming salt and solvent-nonsolvent phase conversion. We examined the effect of two different porous structures (GS and GL) on ADSC growth and proliferation. The GS conduits had better structural stability,permeability, and porosity, as well as better cell viability at 4, 7, and 10 days. The epineurial-like tissue was grown from ADSC-seeded conduits cultured for 7 days in vitro and then implanted into 10 mm rat sciatic nerve defects for evaluation. The regeneration capacity and functional recovery were evaluated by histological staining, electrophysiology, walking track, and functional gait analysis after 6 weeks of implantation. Experimental data indicated that the autograft and ADSC-seeded GS conduits had better functional recovery than the blank conduits and ADSC-seeded GL conduits. The area of regenerated nerve and number of myelinated axons quantified based on the histology also indicated that the autograft and AGS groups performed better than the other two groups. We suggested that ADSCs may interact with endogenous Schwann cells and release neurotrophic factors to promote peripheral nerve regeneration. The design of the conduit may be critical for producing a biohybrid nerve conduit and to provide an epineurial-like support.
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Lai, Hsin Jou, and 賴欣柔. "Development and application of anti-adhesive nerve conduit for peripheral nerve repair." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/2t3ge9.
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Lin, Shih-Ting, and 林詩婷. "Nerve conduit fabrication using microporous chitosan/ collagen composite." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/23398293676504347313.
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碩士國立中興大學
生醫工程研究所
103
In this study, a double-layer nerve conduit scaffold that consists of a inner poly(lactic-co-glycolic acid) (PLGA) scaffold with palisade structure and an outer micro-porous chitosan/collagen composite (CSC) membrane is developed. The PLGA scaffold (length = 5.62 mm, diameter = 1.2 mm) is fabricated using the commonly used soft-lithography process and then rolls into a tube. The micro-porous chitosan/collagen composite membrane is fabricated through lyophilization (freeze-drying) with its pore size being controlled by the weight ratio between chitosan and collagen. CSC properties such as water absorption rate, permeation rate, and biocompatibility are then performed. The chitosan/collagen composite containing 25% of chitosan (CSC-25%) possesses high water absorption rate and permeation rate is adopted as the outer structure of the nerve conduit scaffold. After wrapping a palisade PLGA tube with a CSC-25% membrane to complete a double-layer nerve conduit scaffold, mouse brain neural stem cells KT98 is injected to the inner PLGA scaffold through the pores of the outer CSC membrane. Images of biopsy samples illustrate that KT98 cells can immobilize on the CSC-25% membrane after 7 days’ culture. At the 14th day of culture, KT98 cells have increased their thickness and wrapped the PLGA scaffold. Longitudinal section images further indicate that KT98 cells grow along the palisade structure of the PLGA scaffold.
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HSU, CHIA CHUN, and 徐嘉鈞. "A Study on Chitosan Nerve Conduit Loading aFGF Microsphere." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/30572337613288364681.
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碩士國立臺灣大學
醫學工程學研究所
97
Nerve bridging is suture a biomaterial-made conduit and to overpass the damaged nerve end to end with microsurgery. Peripheral nerve could be bridged between the proximal nerve and the distal stump to restore the function. Nerve conduits could eliminate tension at the healing site and induce the regeneration of axons. Nerve conduits also could permit neurobiological recovery to enhance neural regeneration and stop cells and their secretions from obstructing neural regeneration. In this study, we provide acid fiberblast growth factor to induce the nerve to be regenerated and use PDLLA microsphere for drug delivery system. Chitosan was used to fabricate the nerve conduit. Combining Freeze-Drying method and dipping in the wet soaking method prepare out the conduit containing two kinds structure , and then rolled the material to make nerve conduit with pore and multi-layered. In the experiment, analyze with SDS page method to know the most stable environment for capsule acid fiberblast growth factor. Use bovine serum albumin as model drug to find the release profile of PDLLA microsphere. And test the best dosage in the cell activity experiment of 3T3 fiberblast cell. Prove acid fiberblast growth factor can be released form the PDLLL microsphere in the ELSA test. Observe chitosan nerve conduit structure by the scanning electron microscope. In The experimental result , ethyl acetate is better at the choice of organic phase than methylene chloride, and add ploy-lysine can promote the stable of the acid fiberblast growth factor undergo double emulsion process. Use bovine serum albumin as model drug to find the release profile of PDLLA microsphere. The result indicate PDLLA microsphere can keep more than 14 day releasing. the best activity dosage of cell is 1-10 ng/ml in the cell activity experiment of 3T3 fiberblast cell.for the release sample of six hours and two days, about 0.7 ng/ml acid fiberblast growth factor can be inspected in ELISA test. We can find the PDLLA microsphere can be kept in the porous layer of the chitosan nerve conduit.Combining Freeze-Drying method and dipping in the wet soaking method can prepare out the conduit containing two kinds structure whose non-porous film layer and 100μm pore sponge layer.
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Huang, Chun-Chieh, and 黃俊傑. "The Biocompatibility of Multi-Channel Peripheral Nerve Conduit Manufactured by Chitosan." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/27615677318086520445.
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碩士國立臺灣大學
醫學工程學研究所
93
For peripheral nerve regeneration, it often uses artificial nerve conduits to prevent the nerve from the tension applied during suturing the injured nerve directly. Chitosan is one of the most potential materials to be used for manufacture artificial nerve conduits due to its outstanding characteristics, such as biocompatibility, biodegradability, induce less tissue response and so on. Chitosan is also proved medicinal by FDA so as to make it possible to be used on clinic. In this study, we develop a brand new method, wire-heating and lyophilizing process, for manufacturing nerve conduit, and make it facile and reproducible. The characteristics of chitosan conduits, such as micro surface morphology, crystalline, and the choice of neutralizer are also evaluated. The experiment results show that the chitosan conduits with the hollow channels are highly porous, and are appropiate to use weak base as neutralizer. Using weak base as neutralizer can not only hold the micro-structure but also keep the crystalline of chitosan. The degradation rate test of chitosan conduits also shows that the conduits can provide with a longer lasting structure support during the period of nerve regeneration. Furthermore, we also evaluate the cell viability of chitosan. Schwann Cells were cultured on chitosan membrane, and further on conduits. It shows that chitosan membrane surface modified with biomolecules, one of which laminin was used in this study, can improve the poor condition of cell adhesion to chitosan membrane. However, it was also found that a poor result appeared in the culture of Schwann Cells in chitosan conduits. It is assumed that one reason could be the absence of biomolecular modification, and the other one could be the shape of the channel not being adapted to the cells.
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Lin, Ying-Ting, and 林穎廷. "A novel chitosan nerve conduit with micro and nano hybrid patterns." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/gtcb2q.
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碩士國立中興大學
生醫工程研究所
102
Nerve conduits have been widely used for repairing damaged nerve bundles. However, the repair rate is still far below expectation currently. To enhance the proliferation of nerve cells on nerve conduits, nerve conduits that can mimic the natural environment of human body is a feasible solution. Since the primitive living environment, that is in the scale of nano/micro meter, can influence the growth of nerve cell, it is desirable to fabricate a scaffold mimicking the primitive living environment such that the growth of nerve cells can be well directed. Therefore, a novel chitosan nerve conduit with micro and nano hybrid patterns is proposed in this study. The microelectromechanical system (MEMS) and nickel electroforming techniques were used for the fabrication of the chitosan nerve conduits. The hemispheric array of the barrier layer of an anodic aluminum oxide (AAO) film was used as the substrate. The MEMS process was then used to fabricate micro-structure pattern on the surface of the barrier layer. Following, a nickel replica mold was produced through electroforming using the patterned AAO barrier layer as the template. Scaffolds of chitosan nerve conduit were formed by casting using the synthesized nickel replica mold. Nerve cells were then cultured on the scaffolds. The WST-1 test was used to illustrate the cells proliferation rate. The cell adhesion and morphology were observed through the Hoechst (staining nucleus) and phalloidin (staining cytoskeleton) labeling. It is observed that a micro-structure can only guide the nerve cells to grow along a certain direction, while the proposed micro and nano hybrid structure can successfully guide the growth direction and enhance the proliferation of nerve cells.
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Hsu, Son-Haur, and 許松豪. "Application of Stem Cells, Neurotrophic Factors and Conduit in Nerve Repair." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/18222609648271582087.
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博士國立臺灣大學
動物學研究所
101
Nerve injury causes the death of neural cells and the breakage of nerve fibers resulting in the loss of nerve function. Neuron regeneration faces a difficult challenge due to the highly specialized system and the complex repair mechanism. In this study, according to the concept of tissue engineering and neural regeneration strategy, We use chitosan as a degradable biomaterial to integrate the three main tissue engineering elements: cell, scaffold and cell regulating factors, for achieving the purpose of nerve regeneration. Firstly, self-assembled drug carrier by using chitosan and heparin to adsorb, protect, prolong and enhance the bioactivity of growth factors (also called acidic fibroblast growth factor (aFGF)) was developed and also decrease the fibrosis and prevent adhesion in vivo. Furthermore, chitosan incorporating with carbon nanotube (CNT) can effectively improve the physicochemical properties of chitosan in various applications, especially in mechanical strength and electrical conductivity. In order to make CNT/Chitosan cell friendly most, electric O2-plasma treatment and laminin modification were applied. Successful modification was confirmed by immunolocalization, significantly improved cell adhesion and neurite extension. We hypothesize that CNT/chitosan materials provide functional nerve conduit for healing injured nerves. In this study, the final test used laminin-modified chitosan multi-walled nerve conduit combining with bone marrow stem cells (BMSCs), and grating to bridge in sciatic nerve of SD for 16 weeks. The result is shown that the therapy with stem cell can promote the neuron regeneration to crossover a 10 mm long gap and help more motor neuron to survivor. Moreover, the result is also shown that the degradation of chitosan might cause chronic inflammation which might fail the regeneration of neuron, and the therapy with stem cell can modulate the inflammation to overcome this problem. At last, this study is shown the important of animal experiments: because these data cannot present the material or cell test, the long-term animal experiments is the only way to confirm the safety and the applicability of research results. This paper using many strategy of neuron regeneration from materials, growth factors, cells to animal testing. Hope the results in this study can contribute a little to the research of neuron regeneration.
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Chang, Yo Cheng, and 張祐誠. "Multi-channeled Gelatin Scaffold Incorporating with Neurotrophic Gradient and Nanotopography as Nerve Guidance Conduit for Peripheral Nerve Regeneration." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/hajne4.
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碩士國立清華大學
材料科學工程學系
105
Peripheral nerve injuries affect a great amount of trauma patients annually. Development of nerve conduits will likely allow scientific and medical communities to improve functional recovery after nerve injuries. However, the efficacy of nerve conduits is often compromised by the lack of cells within the conduit, molecular factors enriched microenvironment and the extracellular matrix (ECM) mimetic spatial arrangement for nerve regeneration. In this study, a multi-channeled scaffold combined with aligned nanofibers and neurotrophic gradient (MC/AN/NG) was developed to attract axon outgrowth and mimic the fascicular architecture of ECM. In mechanical test, the result confirmed that a multi-channeled (MC) scaffold crosslinked with microbial transglutaminase (mTG) was stronger as demonstrated by the higher ultimate tensile strength and Young's modulus compared to untreated one. Nerve growth factor (NGF) release profile exhibited a discontinuous concentration gradient from 6.6 ng/mL to 107.2 ng/mL. In in vitro study, differentiated neural stem cells (dNSCs) could extend their neurites along the aligned nanofibrous structure. The cell density increased in higher NGF concentration region of gradient membrane. BDNF promoted myelination more significantly than the non-treated and NGF-treated groups, evidenced by the immunostaining. In in vivo study, the MC/AN/NG scaffold was used for bridging a 15 mm gap in a rabbit sciatic nerve transection model. The MC/AN/NG scaffold achieved functional recovery comparable to autograft as evidenced by significantly improved nerve function and fascicular morphology. From the above result findings, we suggests that the MC/AN/NG scaffold could be a promising nerve guidance conduit for peripheral nerve regeneration.
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Hu, Che lun, and 胡哲綸. "The Bio-effect of Neural Stem/Progenitor Cells on Novel Nerve Conduit." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/52642910322240373830.
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SHIH, YI-AN, and 施弈安. "SHED cells differentiate to nerve cells in chitosan conduit under dynamic culture." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/bbezw8.
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碩士國立臺北科技大學
生物科技研究所
100
Stem cells from human exfoliated deciduous teeth (SHED) are novel stem cell lines. Many studies have confirmed that SHEDs are similar to mesenchymal stem cell differentiated capacity and can be directly obtained from the dental waste, reducing the complexity of surgery problems. 4% chitosan conduit fabricated by the freeze-dried to provide the cell growth of three-dimensional space. Using a revolving oscillator, promote cell differentiation under dynamic culture system. In this study, we measured neural differentiation capacity of SHEDs by Real-time polymerase chain reaction(qPCR), and detected neuronal differentiation associated gene (Nestin、β-III tubulin、GFAP、CNPase). The morphology of SHED cells on chitosan conduit were observed by using confocal microscopy as well as the immunocytochemistry of Nestin and γ-enolase measured. Based on the results, the gene expression of glial cell marker GFAP and CNPase under chitosan conduit are higher than the cells those in growing in the plane culture. In the past, neuroglial cells were an assisting role in neural cells. In recent years, there are many studies indicated that neuroglia can assist the electrical signals. After long time incubation, the cell skeleton protein β-III tubulin of gene expression increased 11 times, β-III tubulin was considered is the early neuronal markers. SHEDs would cluster together in chitosan conduit under dynamic culture. Through the 3D-scaffold and the dynamic system, which can promote SHEDs differentiation into neural cells. Our data indicate that chitosan conduit combined with the dynamic culture significantly help SHEDs differentiation into neuroglial cells. This culture system can be used to animal experimentation, and in the clinical application in future.
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Mohamadi, F., S. Ebrahimi-Barough, M. R. Nourani, K. Mansoori, M. Salehi, A. A. Alizadeh, S. M. Tavangar, Farshid Sefat, S. Sharifi, and J. Ai. "Enhanced sciatic nerve regeneration by human endometrial stem cells in an electrospun poly (ε-caprolactone)/collagen/NBG nerve conduit in rat." 2017. http://hdl.handle.net/10454/16990.
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NoIn recent years, for neurodegenerative diseases therapy, research has focused on the stem cells therapy. Due to promising findings in stem cell therapy, there are various sources of stem cells for transplantation in human. The aim of this study was to evaluate sciatic nerve regeneration in the rat after nerve transaction followed by human endometrial stem cells (hEnSCs) treatment into poly (e-caprolactone)/collagen/nanobioglass (PCL/collagen/NBG) nanofibrous conduits. After treatment of animals, the performance in motor and sensory tests, showed significant improvement in rats treated with hEnSCs as an autograft. H&E images provided from cross-sectional and, longitudinal-sections of the harvested regenerative nerve as well as immunohistochemistry results indicated that regenerative nerve fibres had been formed and accompanied with new blood vessels in the conduit cell group. Due to the advantage of high surface area for cell attachment, it is reported that this electrospun nerve conduit could find more application in cell therapy for nerve regeneration in future, to further improve the functional regeneration outcome, especially for longer nerve defect restoration. In conclusion, our results suggest that the PCL/collagen/NBG nanofibrous conduit filled with hEnSCs is a suitable strategy to improve nerve regeneration after a nerve transaction in rat.
Iran National Science Foundation (INSF) grant number 95849510
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Chen, Sing-De, and 陳興德. "Enhancing cell growth on poly(ε-caprolactone) nerve conduit scaffold surface by chemical modification." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/72808817230675176537.
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碩士雲林科技大學
化學工程與材料工程研究所
96
This study using hybrid nerve growth factor(NGF)/GRGD、NGF/tirofiban to modify PCL scaffold surface in order to enhance bioactivity;PC12 is a model cell used to discus the growth effect by chemical modification. Prepare PCL scaffold,grafting chitosan by glutaradehye,then using SANPAH graft NGF、GRGD、tirofiban、NGF/GRGD、NGF/tirofiban.In ATR-FTIR, 839 cm-1 1279 cm-1 1342 cm-1 peaks demonstrate GRGD has grafted on the PCL surface. In ESCA, there are S atom appears, demonstrate tirofiban grafted on PCL surface. In HPLC, assay GRGD and tirofiban specific peaks,and the graft yield was 85% and 87%.The MTS assay,grafted hybrid NGF/GRGD**>GRGD**>CS ; hybrid NGF/tirofiban*>tirofiban**>CS(**:P<0.05、*:P<0.1), and the cell stain DAPI , shows the same results to MTS. By using chemical modification, grafting NGF/GRGD、NGF/tirofiban,can enhance PC12 cell adhesion and growth. Through the study, grafting NGF/GRGD、NGF/tirofiban can effectively enhance the growth of cell and have good potential applied to nerve guide conduits.
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Lu, Jen-Chieh, and 盧仁傑. "Preparation of highly aligned electrospun hollow fibers and its evaluation as nerve guide conduit." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/36556007520057682685.
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碩士臺北醫學大學
生醫材料暨工程研究所
98
An electrospinning method and new formulation were developed to prepare novel “epitaxial growth-like” highly aligned, mono-layered micron size hollow fibrous membrane. With a co-axial spinneret and a pair of biodegradable polymeric solutions, common electrospinning parameters and a rotating drum collector, an interesting phenomenon was observed. The electrospun fibers were deposited on the same spot on the rotating drum. These fibers piled up and stood up from the surface of the drum as the collecting time increase. The samples were washed with water for 24 hours. SEM observation revealed sheets of mono-layered micron size hollow fibers membrane. These fibers were well aligned and tightly packed, just like the epitaxial growth of some semiconducting materials. According to TGA and XRD analysis, different PLLA concentration in electrospun hollow fibers resulted in the similar thermal properties and crystalline structure. The morphology of electrospun PLLA hollow fibrous membrane changes from random to highly aligned when the PLLA concentration increased. The highly aligned fibrous membrane has better mechanical properties. NIH3T3, PC-12 and dental pulp cells were added into PLLA hollow fibers respectively via bio-electrospinning technique. The PC-12 cells were successfully added into inner core. Flourescein-transfected PC-12 cells, were observed in the electrospun hollow fibers by fluorescent microscope. After addition of NGF into tubes, PC-12 cells attached to the tube wall. Axons of PC-12 cells were successfully induced. It grow along the tube. This perfectly aligned hollow fibrous membrane is considered as highly anisotropic structure scaffold. It mimics some tissue structures, such as nerve tissue, vascular structure, and could be many other applications as well.
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Wei-ChinHuang and 黃偉欽. "Nano-mechanical analyses of myelination process and topographical design of guiding channels for nerve conduit." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/35553457518252878697.
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博士國立成功大學
材料科學及工程學系碩博士班
101
In vitro development of myelinated axons were differentiated by Schwann cells co-cultured with PC12 cells. In first part of this thesis, the three major myelination stages with distinct structural characteristics, mechanical properties and thicknesses around the myelinated axon with various co-culture times were confirmed. The dynamic contact module and continuous depth sensing nano-indentation are used on the myelinated structure to obtain the load-on-sample versus measured displacement curve of a multi-layered myelin sheath, which is used to determine the work required for the nano-indentation tip to penetrate the myelin sheath structure. By analyzing the harmonic contact stiffness versus the measured displacement profile, the results can be used to estimate the three stages of the multi-layered structure on a myelinated axon. In the next part of this thesis, different sizes of morphologically and chemically modified microgrooves were fabricated to evaluate the Schwann cells adhesion and cell alignment on the surface. By all the results of these observations, Schwann cells performed different adhesion properties with different microgrooves designs. Eventually, plano-concave fibers (PCFs) of poly-lactic acid combined advantages of these sizes of microgrooves are designed as a unit of guided channels in nerve conduit. The guided channels designed for supporting Schwann cells to facilitate mass transport and promote nerve regeneration. The surface-modified PCFs are imprinted with linearly patterned grooves (LPGs) to guide adherent Schwann cell elongation and axon extension. After being co-cultured with PC12 neuron-like cells, Schwann cells differentiate into the myelinated type and interact with PC12 axons. The myelinated axons aggregate as a linear bundle and extend along the direction of LPGs on a PCF. The design of PCFs can potentially bridge gaps in injured nerves, improving the therapeutic efficacy of nerve regeneration.
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Ko, Chien-Hsin, and 柯建新. "Biodegradable Bisvinyl Sulfonemethyl-crosslinked Gelatin Conduit Promotes Regeneration after Peripheral Nerve Injury in Adult Rats." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/2qm42e.
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博士中國醫藥大學
基礎醫學研究所博士班
106
In our previous study, we found that gelatin-based materials exhibit good conductivity and are non- cytotoxic. In this study, gelatin was cross-linked with bisvinyl sulfonemethyl (BVSM) to fabricate a biodegradable conduit for peripheral nerve repair. First, BVSM on the prepared conduit was characterized to determine its mechanical properties and contact angle. The maximum tensile strength and water contact angle of the gelatin-BVSM conduits were 23 ± 4.8 MPa and 74.7 ± 9°, which provided sufficient mechanical strength to resist muscular contraction; additionally, the surface was hydrophilic. Cytotoxicity and apoptosis assays using Schwann cells demonstrated that the gelatin-BVSM conduits are non-cytotoxic. Next, we examined the neuronal electrophysiology, animal behavior, neuronal connectivity, macrophage infiltration, calcitonin gene-related peptide localization and expression, as well as the expression levels of nerve regeneration-related proteins. The number of fluorogold-labelled cells and histological analysis of the gelatin-BVSM nerve conduits was similar to that observed with the clinical use of silicone rubber conduits after 8 weeks of repair. Therefore, our results demonstrate that gelatin-BVSM conduits are promising substrates for application as bioengineered grafts for nerve tissue regeneration.
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Chen, Chien-Chang, and 陳建璋. "The efficacy of 3D-printable polyurethane conduit with neuron schwann cell spheroids for peripheral nerve regeneration." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ht83xt.
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