The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Molly S. Shoichet - One of the best experts on this subject based on the ideXlab platform.
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7.31 Biomaterials for Spinal Cord Repair
Comprehensive Biomaterials II, 2017Co-Authors: M.d. Baumann, Jason C. Stanwick, I.e. Donaghue, Molly S. ShoichetAbstract:Traumatic spinal cord injury results in permanent neurological and functional deficits as a result of tissue damage and degeneration. The local inhibitory environment resulting from an injury poses a significant impediment to spinal cord regeneration and is one of the reasons why functional improvement will require multiple treatment strategies. Several biomaterial-based strategies have been investigated in animal models. These approaches can be broadly classified as either drug delivery or cell delivery strategies. Hydrogels and polymeric particles, used for controlled release of therapeutic biomolecules, circumvent the blood–spinal cord barrier when delivered directly at the injury site and thereby avoid the need for invasive delivery techniques. Nerve Guidance Channels and scaffolds, used for cell delivery, can be engineered to provide the chemical and mechanical cues necessary to support implanted cells and promote tissue repair. These biomaterials provide an opportunity to achieve effective treatment options through the improvement of the delivery of therapeutics and cells to the injured spinal cord.
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Biomaterials for Spinal Cord Repair
Comprehensive Biomaterials, 2011Co-Authors: M.d. Baumann, Jason C. Stanwick, I.e. Donaghue, Molly S. ShoichetAbstract:Traumatic spinal cord injury results in permanent neurological and functional deficits as a result of tissue damage and degeneration. The local inhibitory environment resulting from an injury poses a significant impediment to spinal cord regeneration and is one of the reasons why functional improvement will require multiple treatment strategies. Several biomaterial-based strategies have been investigated in animal models. These approaches can be broadly classified as either drug delivery or cell delivery strategies. Hydrogels and polymeric particles, used for controlled release of therapeutic biomolecules, circumvent the blood–spinal cord barrier when delivered directly at the injury site and thereby avoid the need for invasive delivery techniques. Nerve Guidance Channels and scaffolds, used for cell delivery, can be engineered to provide the chemical and mechanical cues necessary to support implanted cells and promote tissue repair. These biomaterials provide an opportunity to achieve effective treatment options through the improvement of the delivery of therapeutics and cells to the injured spinal cord.
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Incorporation of protein-eluting microspheres into biodegradable Nerve Guidance Channels for controlled release
Journal of controlled release : official journal of the Controlled Release Society, 2005Co-Authors: Alex Goraltchouk, Vanessa I. Scangav.i. Scanga, Cindi M. Morshead, Molly S. ShoichetAbstract:Nerve Guidance Channels (NGCs) promote axonal regeneration after transection injury of the peripheral Nerve or spinal cord, yet this regeneration is limited. To enhance regeneration further, we hypothesize that localized delivery of therapeutic molecules combined with the NGC is required. In an attempt to achieve such an NGC, we designed and synthesized a novel NGC in which protein-encapsulated microspheres were stably incorporated into the tube wall. Specifically, poly(lactide-co-glycolide) (PLGA 50/50) microspheres were physically entrapped in the annulus between two concentric tubes, consisting of a chitosan inner tube and a chitin outer tube. Taking advantage of the extensive shrinking that the outer chitin tube undergoes with drying, >15 mg of microspheres were loaded within the tube walls. Using BSA-encapsulated microspheres as the model drug delivery system, BSA was released from microsphere loaded tubes (MLTs) for 84 days, and from freely suspended PLGA microspheres for 70 days. An initial burst release was observed for both MLTs and free microspheres, followed by a degradation-controlled release profile that resulted in a higher release rate from MLTs initially, which was then attenuated likely due to the buffering effect of chitin and chitosan tubes. Epidermal growth factor (EGF), co-encapsulated with BSA in PLGA 50/50 microspheres in MLTs, was released for 56 days with a similar profile to that of BSA. Released EGF was found to be bioactive for at least 14 days as assessed by a neurosphere forming bioassay.
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synthesis of degradable poly l lactide co ethylene glycol porous tubes by liquid liquid centrifugal casting for use as Nerve Guidance Channels
Biomaterials, 2005Co-Authors: Alex Goraltchouk, Thomas Freier, Molly S. ShoichetAbstract:Biodegradable Nerve Guidance Channels are advantageous, obviating the need for their removal after regeneration; however, most Channels lack the appropriate mechanical properties for soft tissue implantation and/or degrade too quickly, resulting in reduced regeneration and necessitating the need for the design of polymers with tunable degradation profiles and mechanical properties. We designed a series of biodegradable polymeric hydrogel tubes consisting of L-lactide (LLA) and polyethylene glycol (PEG) where both the ratio of LLA to PEG and PEG molar mass were varied. By adjusting the PEG:LLA ratio and the molecular weight of the PEG oligomer we were able to control degradation and mechanical properties of our polymers. By incorporating methacrylate (MA) groups on both termini of the linear oligomers, porous tubes were synthesized by a redox-initiated free radical mechanism during a liquid-liquid centrifugal casting process. The tube wall had a bead-like morphology, as determined by SEM, which was reminiscent of previous porous hydrogel tubes synthesized by the same method. Tubes swelled with degradation to 160 vol%, or 640 wt%, and an increased radius calculated at 1.26 times. Those tubes with greater PEG content and PEG molar mass degraded faster than those with greater LLA content, as was expected. Interestingly, the wall morphology changed with degradation to a fiber-like structure and the mechanical properties decreased with degradation. By correlating the accelerated degradation study to a physiologic one, these porous hydrogel tubes were stable for an equivalent of 1.5 months, after which the mechanical properties began to deteriorate. This study demonstrates how porous hydrogel tubes can be designed to meet tissue regeneration criteria by tuning the formulation chemistry and specifically how the ratio of hydrophobic/crystalline LLA and hydrophilic/amorphous PEG impact tube properties.
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Nerve Guidance Channels as drug delivery vehicles.
Biomaterials, 2005Co-Authors: Alexandra Piotrowicz, Molly S. ShoichetAbstract:Abstract Nerve Guidance Channels (NGCs) have been shown to facilitate regeneration after transection injury to the peripheral Nerve or spinal cord. Various therapeutic molecules, including neurotrophic factors, have improved regeneration and functional recovery after injury when combined with NGCs; however, their impact has not been maximized partly due to the lack of an appropriate drug delivery system. To address this limitation, Nerve growth factor (NGF) was incorporated into NGCs of poly(2-hydroxyethyl methacrylate-co-methyl methacrylate), P(HEMA-co-MMA). The NGCs were synthesized by a liquid–liquid centrifugal casting process and three different methods of protein incorporation were compared in terms of protein distribution and NGF release profile: (1) NGF was encapsulated (with BSA) in biodegradable poly( d , l -lactide-co-glycolide) 85/15 microspheres, which were combined with a PHEMA polymerization formulation and coated on the inside of pre-formed NGCs by a second liquid–liquid centrifugal casting technique; (2) pre-formed NGCs were imbibed with a solution of NGF/BSA and (3) NGF/BSA alone was combined with a PHEMA formulation and coated on the inside of pre-formed NGCs by a second liquid–liquid centrifugal casting technique. Using a fluorescently labelled model protein, the distribution of proteins in NGCs prepared with a coating of either protein-loaded microspheres or protein alone was found to be confined to the inner PHEMA layer. Sustained release of NGF was achieved from NGCs with either NGF-loaded microspheres or NGF alone incorporated into the inner layer, but not from Channels imbibed with NGF. By day 28, NGCs with microspheres released a total of 220 pg NGF/cm of channel whereas those NGCs imbibed with NGF released 1040 pg/cm and those NGCs with NGF incorporated directly in a PHEMA layer released 8624 pg/cm. The release of NGF from NGCs with microspheres was limited by a slow-degrading microsphere formulation and by the maximum amount of microspheres that could be incorporated into the NGCs structure. Notwithstanding, the liquid–liquid centrifugal casting process is promising for localized and controlled release of multiple factors that are key to tissue regeneration.
Patrick Aebischer - One of the best experts on this subject based on the ideXlab platform.
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robots and biological systems towards a new bionics
2012Co-Authors: P Dario, Giulio Sandini, Patrick AebischerAbstract:1. Vision and Dynamic Systems.- Active Perception and Exploratory Robotics.- Object Identification and Search: Animate Vision Alternatives to Image Interpretation.- A Model of Human Feature Detection Based on Matched Filters.- Visualizing and Understanding Patterns of Brain Architecture.- Dynamic Vision.- A Model of the Acquisition of Object Representations in Human 3D Visual Recognition.- 2. Hands and Tactile Perception.- The Perception of Mechanical Stimuli Through the Skin of the Hand and Its Physiological Bases.- Borrowing Some Ideas from Biological Manipulators to Design an Artificial One.- Mechanical Design for Whole-Arm Manipulation.- Whole-Hand Manipulation: Design of an Articulated Hand Exploiting All Its Parts to Increase Dexterity.- Stable Grasping and Manipulation by a Multifinger Hand with the Capability of Compliance Control.- 3. Locomotion.- Mobile Robots - the Lessons from Nature.- Quadruped Walking Machine - Creation of the Model of Motion.- Biped Locomotion by FNS: Control Issues and an ANN Implementation.- How Fast Can a Legged Robot Run?.- Robot Biped Walking Stabilized with Trunk Motion.- 4. Intelligent Motor Control.- A New Concept of the Role of Proprioceptive and Recurrent Inhibitory Feedback in Motor Control.- Analogic Models for Robot Programming.- Structural Constraints and Computational Problems in Motor Control.- Motion Control in Intelligent Machines.- Control of Contact in Robots and Biological Systems.- Motor Control Simulation of Time Optimal Fast Movement in Man.- Constraints on Underspecified Target Trajectories.- Proposal for a Pattern Matching Task Controller for Sensor-Based Coordination of Robot Motions.- Sensory-Motor Mapping with a Sequential Network.- 5. Design Technologies.- Flexible Robot Manipulators and Grippers: Relatives of Elephant Trunks and Squid Tentacles.- Progress in the Design and Control of Pseudomuscular Linear Actuators.- Shape Memory Alloy Linear Actuators for Tendon-Based Biomorphic Actuating Systems.- CCD Retina and Neural Net Processor.- Retina-Like CCD Sensor for Active Vision.- Designing Artificial Structures from Biological Models.- Design Strategies for Gas and Odour Sensors Which Mimic the Olfactory System.- 6. Interfacing Robots to Nervous System.- Multi-Electrode Stimulation of Myelinated Nerve Fibers.- The Role of Materials in Designing Nerve Guidance Channels and Chronic Neural Interfaces.- Regeneration-Type Peripheral Nerve Interfaces for Direct Man/Machine Communication.- Integrated Bioelectronic Transducers.- 7. Robot Societies and Self-Organization.- A Robot Being.- Swarm Intelligence in Cellular Robotic Systems.- A Control Architecture for Cooperative Intelligent Robots.- Cellular Robotics - Construction of Complicated Systems from Simple Functions.
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gdnf and ngf released by synthetic Guidance Channels support sciatic Nerve regeneration across a long gap
European Journal of Neuroscience, 2002Co-Authors: Eric G. Fine, Anne D. Zurn, Patrick Aebischer, Isabelle Decosterd, Michael PapaloizosAbstract:The present work was performed to determine the ability of neurotrophic factors to allow axonal regeneration across a 15-mm-long gap in the rat sciatic Nerve. Synthetic Nerve Guidance Channels slowly releasing NGF and GDNF were fabricated and sutured to the cut ends of the Nerve to bridge the gap. After 7 weeks, Nerve cables had formed in nine out of ten Channels in both the NGF and GDNF groups, while no neuronal cables were present in the control group. The average number of myelinated axons at the midpoint of the regenerated Nerves was significantly greater in the presence of GDNF than NGF (4942 +/-1627 vs. 1199 +/-431, P < or = 0.04). A significantly greater number of neuronal cells in the GDNF group, when compared to the NGF group, retrogradely transported FluoroGold injected distal to the injury site before explantation. The total number of labelled motoneurons observed in the ventral horn of the spinal cord was 98.1 +/-23.4 vs. 20.0 +/-8.5 (P < or = 0.001) in the presence of GDNF and NGF, respectively. In the dorsal root ganglia, 22.7% +/- 4.9% vs. 3.2% +/-1.9% (P +/-0.005) of sensory neurons were labelled retrogradely in the GDNF and NGF treatment groups, respectively. The present study demonstrates that, sustained delivery of GDNF and NGF to the injury site, by synthetic Nerve Guidance Channels, allows regeneration of both sensory and motor axons over long gaps; GDNF leads to better overall regeneration in the sciatic Nerve.
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Nerve growth factor- and neurotrophin-3-releasing Guidance Channels promote regeneration of the transected rat dorsal root.
Experimental neurology, 2001Co-Authors: Jocelyne Bloch, Eric G. Fine, Nicolas Bouche, Anne D. Zurn, Patrick AebischerAbstract:Dorsal roots have a limited regeneration capacity after transection. To improve Nerve regeneration, the growth-promoting effects of the neurotrophins Nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) were evaluated. The proteins were continuously released by synthetic Nerve Guidance Channels bridging a 4-mm gap in the transected dorsal root. Four weeks after lesion, the regenerated Nerve cables were analyzed for the presence of myelinated and unmyelinated axons. While BDNF showed a limited effect on axonal regeneration (863 +/- 39 axons/regenerated Nerve, n = 6), NGF (1843 +/- 482) and NT-3 (1495 +/- 449) powerfully promoted regeneration of myelinated axons compared to Channels releasing the control protein bovine serum albumin (293 +/- 39). In addition, NGF, but not BDNF nor NT-3, had a potent effect on the regeneration of unmyelinated axons (NGF, 55 +/- 1.4; BDNF, 4 +/- 0.3; NT-3, 4.7 +/- 0.3 axons/100 microm(2); n = 6). The present study suggests that synthetic Nerve Guidance Channels slowly and continuously releasing the neurotrophins NGF and NT-3 can overcome the limited regeneration of transected dorsal root.
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in vivo performance of a new biodegradable polyester urethane system used as a Nerve Guidance channel
Biomaterials, 1998Co-Authors: M Borkenhagen, R C Stoll, P Neuenschwander, Ulrich W Suter, Patrick AebischerAbstract:Biodegradable Nerve Guidance Channels (NGCs) represent a promising alternative to current clinical Nerve repair procedures. To be suitable as a NGC material, the polymer system should possess elastomeric properties and degrade at a defined rate without interfering with the regenerating environment. Polymers made of non-crystallizable blocks of poly[glycolide-co-(epsilon-caprolactone)]-diol and crystallizable blocks of poly[(R)-3-hydroxybutyric acid-co-(R)-3-hydroxyvaleric acid]-diol (PHB) can be modulated so as to respond to those criteria. Tubular structures were fabricated from three different types of materials containing either 41, 17 or 8 wt% PHB. Nerve regeneration through a 10 mm long NGC using a transected sciatic Nerve model with an 8 mm gap was studied in rats at 4, 12 and 24 weeks. Out of 26 implanted NGCs, 23 contained regenerated tissue cables centrally located within the channel lumen and composed of numerous myelinated axons and Schwann cells. No significant difference in the degree of regeneration was observed between the various channel types. The inflammatory reaction associated with the polymer degradation had not interfered with the Nerve regeneration process. Macrophages and giant cells surrounded polymer material remnants. A weight loss of 33, 74 and 88% for polymers containing 41, 17 and 8 wt% PHB was observed after 24 weeks by nuclear magnetic resonance (NMR) anaylsis, respectively. In all cases, the polymer fragments had a porous appearance with multiple surface cracks as evidenced by scanning electron microscopical analysis. Guidance Channels made of 8 wt% PHB containing polymer displayed the highest degree of degradation at 24 weeks with only small polymer fragments remaining. The present study suggests that this new biodegradable elastomeric polymeric material holds promises for its utilization as Nerve Guidance Channels.
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Three-dimensional extracellular matrix engineering in the nervous system.
Journal of biomedical materials research, 1998Co-Authors: M Borkenhagen, J.‐f. Clémence, H. Sigrist, Patrick AebischerAbstract:Growing neurites are guided through their environment during development and regeneration via different cellular and extracellular matrix (ECM) molecular cues. To mimic cell-matrix interactions, a three-dimensional (3D) hydrogel-based ECM equivalent containing a covalently immobilized laminin oligopeptide sequence was designed to facilitate Nerve regeneration. This study illustrates that the oligopeptide domain CDPGYIGSR covalently linked to an agarose gel as a bioartificial 3D substrate successfully supports neurite outgrowth from dorsal root ganglia (DRG) in vitro. The specificity of the neurite promoting activity was illustrated through the inhibition of neurite outgrowth from DRG in a CDPGYIGSR-derivatized gel in the presence of solubilized CDPGYIGSR peptide. Gels derivatized with CDPGYIGSK and CDPGRGSYI peptides stimulated a smaller increase of neurite outgrowth. In vivo experiments revealed the capability of a CDPGYIGSR-derivatized gel to enhance Nerve regeneration in a transected rat dorsal root model compared to an underivatized gel, a CDPGRGSYI gel, and saline-filled Nerve Guidance Channels. These data suggest the feasibility of a 3D hydrogel-based ECM equivalent capable of enhancing neurite outgrowth in vitro and in vivo.
Zbigniew Pasieka - One of the best experts on this subject based on the ideXlab platform.
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in vivo evaluation of Nerve Guidance Channels of ptmc plla porous biomaterial
Archives of Medical Science, 2015Co-Authors: Radoslaw A. Wach, Agnieszka Adamus, Janusz M. Rosiak, Bartlomiej Grobelski, Jaroslaw Cala, Karolina Kowalskaludwicka, Zbigniew PasiekaAbstract:INTRODUCTION Peripheral Nerve disruptions, frequently occurring during limb injuries, give rise to serious complications of patients recovery resulting from limitations in neural tissue regeneration capabilities. To overcome this problem bridging techniques utilizing Guidance Channels gain their importance. Biodegradable polymeric tubes seem to be more prospective then non-degradable materials - no necessity of implant removal and possibilities of release of incorporated drugs or biologically active agents that may support Nerve regeneration process are the main advantages. MATERIAL AND METHODS Polymer blend of commercial poly(L-lactic acid) (PLLA) and in-house synthesized poly(trimethylene carbonate) (PTMC) were processed in an organic solvent - phase inversion process on a supporting rod - to form a Guidance porous tube of 1.1 mm inner diameter. In vivo experiments on rat's cut femoral Nerve by using either the tubes or end-to-end suturing (control group) involved 22 and 19 rats, respectively. Motor recovery of operated limbs, neuroma occurrence and histopathology of explanted Nerves were evaluated after 30, 60 and 90 days of implantation. RESULTS Motor recovery of the limbs was of similar rate for the two animal groups. The neuroma formation was evident in over 90% control specimens, while for the bridging group it was less than 40% of all evaluable samples (p = 0.0022). Biocompatibility of applied materials was affirmed by moderate tissue response. CONCLUSIONS Application of the biodegradable PLLA/PTMC polymeric tubes effectively supports regeneration of discontinued Nerves. The applied material prevents neuroma formation, by reducing the scar tissue formation time and, thus, accelerating the process of neural tissue restoration.
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In vivo evaluation of Nerve Guidance Channels of PTMC/PLLA porous biomaterial.
Archives of medical science : AMS, 2013Co-Authors: Radoslaw A. Wach, Agnieszka Adamus, Janusz M. Rosiak, Karolina Kowalska-ludwicka, Bartlomiej Grobelski, Jaroslaw Cala, Zbigniew PasiekaAbstract:INTRODUCTION Peripheral Nerve disruptions, frequently occurring during limb injuries, give rise to serious complications of patients recovery resulting from limitations in neural tissue regeneration capabilities. To overcome this problem bridging techniques utilizing Guidance Channels gain their importance. Biodegradable polymeric tubes seem to be more prospective then non-degradable materials - no necessity of implant removal and possibilities of release of incorporated drugs or biologically active agents that may support Nerve regeneration process are the main advantages. MATERIAL AND METHODS Polymer blend of commercial poly(L-lactic acid) (PLLA) and in-house synthesized poly(trimethylene carbonate) (PTMC) were processed in an organic solvent - phase inversion process on a supporting rod - to form a Guidance porous tube of 1.1 mm inner diameter. In vivo experiments on rat's cut femoral Nerve by using either the tubes or end-to-end suturing (control group) involved 22 and 19 rats, respectively. Motor recovery of operated limbs, neuroma occurrence and histopathology of explanted Nerves were evaluated after 30, 60 and 90 days of implantation. RESULTS Motor recovery of the limbs was of similar rate for the two animal groups. The neuroma formation was evident in over 90% control specimens, while for the bridging group it was less than 40% of all evaluable samples (p = 0.0022). Biocompatibility of applied materials was affirmed by moderate tissue response. CONCLUSIONS Application of the biodegradable PLLA/PTMC polymeric tubes effectively supports regeneration of discontinued Nerves. The applied material prevents neuroma formation, by reducing the scar tissue formation time and, thus, accelerating the process of neural tissue restoration.
Radoslaw A. Wach - One of the best experts on this subject based on the ideXlab platform.
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in vivo evaluation of Nerve Guidance Channels of ptmc plla porous biomaterial
Archives of Medical Science, 2015Co-Authors: Radoslaw A. Wach, Agnieszka Adamus, Janusz M. Rosiak, Bartlomiej Grobelski, Jaroslaw Cala, Karolina Kowalskaludwicka, Zbigniew PasiekaAbstract:INTRODUCTION Peripheral Nerve disruptions, frequently occurring during limb injuries, give rise to serious complications of patients recovery resulting from limitations in neural tissue regeneration capabilities. To overcome this problem bridging techniques utilizing Guidance Channels gain their importance. Biodegradable polymeric tubes seem to be more prospective then non-degradable materials - no necessity of implant removal and possibilities of release of incorporated drugs or biologically active agents that may support Nerve regeneration process are the main advantages. MATERIAL AND METHODS Polymer blend of commercial poly(L-lactic acid) (PLLA) and in-house synthesized poly(trimethylene carbonate) (PTMC) were processed in an organic solvent - phase inversion process on a supporting rod - to form a Guidance porous tube of 1.1 mm inner diameter. In vivo experiments on rat's cut femoral Nerve by using either the tubes or end-to-end suturing (control group) involved 22 and 19 rats, respectively. Motor recovery of operated limbs, neuroma occurrence and histopathology of explanted Nerves were evaluated after 30, 60 and 90 days of implantation. RESULTS Motor recovery of the limbs was of similar rate for the two animal groups. The neuroma formation was evident in over 90% control specimens, while for the bridging group it was less than 40% of all evaluable samples (p = 0.0022). Biocompatibility of applied materials was affirmed by moderate tissue response. CONCLUSIONS Application of the biodegradable PLLA/PTMC polymeric tubes effectively supports regeneration of discontinued Nerves. The applied material prevents neuroma formation, by reducing the scar tissue formation time and, thus, accelerating the process of neural tissue restoration.
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In vivo evaluation of Nerve Guidance Channels of PTMC/PLLA porous biomaterial.
Archives of medical science : AMS, 2013Co-Authors: Radoslaw A. Wach, Agnieszka Adamus, Janusz M. Rosiak, Karolina Kowalska-ludwicka, Bartlomiej Grobelski, Jaroslaw Cala, Zbigniew PasiekaAbstract:INTRODUCTION Peripheral Nerve disruptions, frequently occurring during limb injuries, give rise to serious complications of patients recovery resulting from limitations in neural tissue regeneration capabilities. To overcome this problem bridging techniques utilizing Guidance Channels gain their importance. Biodegradable polymeric tubes seem to be more prospective then non-degradable materials - no necessity of implant removal and possibilities of release of incorporated drugs or biologically active agents that may support Nerve regeneration process are the main advantages. MATERIAL AND METHODS Polymer blend of commercial poly(L-lactic acid) (PLLA) and in-house synthesized poly(trimethylene carbonate) (PTMC) were processed in an organic solvent - phase inversion process on a supporting rod - to form a Guidance porous tube of 1.1 mm inner diameter. In vivo experiments on rat's cut femoral Nerve by using either the tubes or end-to-end suturing (control group) involved 22 and 19 rats, respectively. Motor recovery of operated limbs, neuroma occurrence and histopathology of explanted Nerves were evaluated after 30, 60 and 90 days of implantation. RESULTS Motor recovery of the limbs was of similar rate for the two animal groups. The neuroma formation was evident in over 90% control specimens, while for the bridging group it was less than 40% of all evaluable samples (p = 0.0022). Biocompatibility of applied materials was affirmed by moderate tissue response. CONCLUSIONS Application of the biodegradable PLLA/PTMC polymeric tubes effectively supports regeneration of discontinued Nerves. The applied material prevents neuroma formation, by reducing the scar tissue formation time and, thus, accelerating the process of neural tissue restoration.
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Nerve Guidance Channels based on plla ptmc biomaterial
Journal of Applied Polymer Science, 2013Co-Authors: Radoslaw A. Wach, Agnieszka Adamus, Joanna Dzierzawska, Alicja Olejnik, Janusz M. RosiakAbstract:Biodegradable polymers of poly(lactic acid) (PLLA) and synthesized in-house poly(trimethylene carbonate) (PTMC) with admixture of water-soluble methyl cellulose (MC) were used for development of Nerve Guidance tubes for peripheral nervous system regeneration after injury. Fabrication method involved phase separation of viscous dixane solution of polymers mixture seat on a rod in a proper nonsolvent, which resulted in tubular structure of large porosity. Influence of electron beam sterilization on molecular weight, thermal properties of the polymers, and mechanical performance of the tubes was evaluated. Admixture of hydrophilic MC to synthetic polymers resulted in modification of mechanical properties of the Channels. Extraction of MC showed potential of the tubes for releasing water-soluble bioactive molecules, such as for instance growth factors. Basic in vitro MTT and LDH assays showed no cytotoxic effect of manufactured tubes, therefore, animal experimentations may be considered. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
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Nerve Guidance Channels based on PLLA–PTMC biomaterial
Journal of Applied Polymer Science, 2012Co-Authors: Radoslaw A. Wach, Agnieszka Adamus, Alicja K. Olejnik, Joanna Dzierzawska, Janusz M. RosiakAbstract:Biodegradable polymers of poly(lactic acid) (PLLA) and synthesized in-house poly(trimethylene carbonate) (PTMC) with admixture of water-soluble methyl cellulose (MC) were used for development of Nerve Guidance tubes for peripheral nervous system regeneration after injury. Fabrication method involved phase separation of viscous dixane solution of polymers mixture seat on a rod in a proper nonsolvent, which resulted in tubular structure of large porosity. Influence of electron beam sterilization on molecular weight, thermal properties of the polymers, and mechanical performance of the tubes was evaluated. Admixture of hydrophilic MC to synthetic polymers resulted in modification of mechanical properties of the Channels. Extraction of MC showed potential of the tubes for releasing water-soluble bioactive molecules, such as for instance growth factors. Basic in vitro MTT and LDH assays showed no cytotoxic effect of manufactured tubes, therefore, animal experimentations may be considered. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
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Degradation of Nerve Guidance Channels based on a poly(l-lactic acid) poly(trimethylene carbonate) biomaterial
Polymer Degradation and Stability, 2012Co-Authors: Agnieszka Adamus, Radoslaw A. Wach, Alicja K. Olejnik, Joanna Dzierzawska, Janusz M. RosiakAbstract:Poly(l-lactic acid) (PLLA) and in-house synthesized poly(trimethylene carbonate) (PTMC) were used for development of Nerve Guidance tubes for support of peripheral nervous system regeneration after an injury. Phase separation of a viscous solution of the polymer mixture on a rod in a non-solvent resulted in fabrication of tubular structure of large porosity. After radiation sterilization by electron beam (EB) applied to assure safety of the product, tensile properties and elasticity of manufactured tubes were sufficient for proposed application. Influence of in vitro hydrolytic degradation on molecular weight, thermal properties of the polymers, morphology and mechanical properties of the tubes was evaluated. Besides minor mass loss in the course of 12 months hydrolytic degradation, molecular weight of PLLA component decreased steadily due to hydrolysis of ester bonds. Consequently changes in thermal properties of the polymers such as change in glass transition and melting temperatures were identified. Admixture of methyl cellulose (MC) to PLLA and PTMC synthetic polymers resulted in slight change of mechanical performance of the Channels after an initial two weeks of degradation since this water-soluble polymer of natural origin was extracted from the synthetic polymer matrix. Other parameters of the tube and those of synthetic polymers were not affected by the presence of MC. Based on the experimental data, it is confirmed that proposed polymeric material of PLLA/PTMC blend with and without addition of MC is suitable for further biological and in vivo study.
Janusz M. Rosiak - One of the best experts on this subject based on the ideXlab platform.
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in vivo evaluation of Nerve Guidance Channels of ptmc plla porous biomaterial
Archives of Medical Science, 2015Co-Authors: Radoslaw A. Wach, Agnieszka Adamus, Janusz M. Rosiak, Bartlomiej Grobelski, Jaroslaw Cala, Karolina Kowalskaludwicka, Zbigniew PasiekaAbstract:INTRODUCTION Peripheral Nerve disruptions, frequently occurring during limb injuries, give rise to serious complications of patients recovery resulting from limitations in neural tissue regeneration capabilities. To overcome this problem bridging techniques utilizing Guidance Channels gain their importance. Biodegradable polymeric tubes seem to be more prospective then non-degradable materials - no necessity of implant removal and possibilities of release of incorporated drugs or biologically active agents that may support Nerve regeneration process are the main advantages. MATERIAL AND METHODS Polymer blend of commercial poly(L-lactic acid) (PLLA) and in-house synthesized poly(trimethylene carbonate) (PTMC) were processed in an organic solvent - phase inversion process on a supporting rod - to form a Guidance porous tube of 1.1 mm inner diameter. In vivo experiments on rat's cut femoral Nerve by using either the tubes or end-to-end suturing (control group) involved 22 and 19 rats, respectively. Motor recovery of operated limbs, neuroma occurrence and histopathology of explanted Nerves were evaluated after 30, 60 and 90 days of implantation. RESULTS Motor recovery of the limbs was of similar rate for the two animal groups. The neuroma formation was evident in over 90% control specimens, while for the bridging group it was less than 40% of all evaluable samples (p = 0.0022). Biocompatibility of applied materials was affirmed by moderate tissue response. CONCLUSIONS Application of the biodegradable PLLA/PTMC polymeric tubes effectively supports regeneration of discontinued Nerves. The applied material prevents neuroma formation, by reducing the scar tissue formation time and, thus, accelerating the process of neural tissue restoration.
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In vivo evaluation of Nerve Guidance Channels of PTMC/PLLA porous biomaterial.
Archives of medical science : AMS, 2013Co-Authors: Radoslaw A. Wach, Agnieszka Adamus, Janusz M. Rosiak, Karolina Kowalska-ludwicka, Bartlomiej Grobelski, Jaroslaw Cala, Zbigniew PasiekaAbstract:INTRODUCTION Peripheral Nerve disruptions, frequently occurring during limb injuries, give rise to serious complications of patients recovery resulting from limitations in neural tissue regeneration capabilities. To overcome this problem bridging techniques utilizing Guidance Channels gain their importance. Biodegradable polymeric tubes seem to be more prospective then non-degradable materials - no necessity of implant removal and possibilities of release of incorporated drugs or biologically active agents that may support Nerve regeneration process are the main advantages. MATERIAL AND METHODS Polymer blend of commercial poly(L-lactic acid) (PLLA) and in-house synthesized poly(trimethylene carbonate) (PTMC) were processed in an organic solvent - phase inversion process on a supporting rod - to form a Guidance porous tube of 1.1 mm inner diameter. In vivo experiments on rat's cut femoral Nerve by using either the tubes or end-to-end suturing (control group) involved 22 and 19 rats, respectively. Motor recovery of operated limbs, neuroma occurrence and histopathology of explanted Nerves were evaluated after 30, 60 and 90 days of implantation. RESULTS Motor recovery of the limbs was of similar rate for the two animal groups. The neuroma formation was evident in over 90% control specimens, while for the bridging group it was less than 40% of all evaluable samples (p = 0.0022). Biocompatibility of applied materials was affirmed by moderate tissue response. CONCLUSIONS Application of the biodegradable PLLA/PTMC polymeric tubes effectively supports regeneration of discontinued Nerves. The applied material prevents neuroma formation, by reducing the scar tissue formation time and, thus, accelerating the process of neural tissue restoration.
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Nerve Guidance Channels based on plla ptmc biomaterial
Journal of Applied Polymer Science, 2013Co-Authors: Radoslaw A. Wach, Agnieszka Adamus, Joanna Dzierzawska, Alicja Olejnik, Janusz M. RosiakAbstract:Biodegradable polymers of poly(lactic acid) (PLLA) and synthesized in-house poly(trimethylene carbonate) (PTMC) with admixture of water-soluble methyl cellulose (MC) were used for development of Nerve Guidance tubes for peripheral nervous system regeneration after injury. Fabrication method involved phase separation of viscous dixane solution of polymers mixture seat on a rod in a proper nonsolvent, which resulted in tubular structure of large porosity. Influence of electron beam sterilization on molecular weight, thermal properties of the polymers, and mechanical performance of the tubes was evaluated. Admixture of hydrophilic MC to synthetic polymers resulted in modification of mechanical properties of the Channels. Extraction of MC showed potential of the tubes for releasing water-soluble bioactive molecules, such as for instance growth factors. Basic in vitro MTT and LDH assays showed no cytotoxic effect of manufactured tubes, therefore, animal experimentations may be considered. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
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Nerve Guidance Channels based on PLLA–PTMC biomaterial
Journal of Applied Polymer Science, 2012Co-Authors: Radoslaw A. Wach, Agnieszka Adamus, Alicja K. Olejnik, Joanna Dzierzawska, Janusz M. RosiakAbstract:Biodegradable polymers of poly(lactic acid) (PLLA) and synthesized in-house poly(trimethylene carbonate) (PTMC) with admixture of water-soluble methyl cellulose (MC) were used for development of Nerve Guidance tubes for peripheral nervous system regeneration after injury. Fabrication method involved phase separation of viscous dixane solution of polymers mixture seat on a rod in a proper nonsolvent, which resulted in tubular structure of large porosity. Influence of electron beam sterilization on molecular weight, thermal properties of the polymers, and mechanical performance of the tubes was evaluated. Admixture of hydrophilic MC to synthetic polymers resulted in modification of mechanical properties of the Channels. Extraction of MC showed potential of the tubes for releasing water-soluble bioactive molecules, such as for instance growth factors. Basic in vitro MTT and LDH assays showed no cytotoxic effect of manufactured tubes, therefore, animal experimentations may be considered. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
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Degradation of Nerve Guidance Channels based on a poly(l-lactic acid) poly(trimethylene carbonate) biomaterial
Polymer Degradation and Stability, 2012Co-Authors: Agnieszka Adamus, Radoslaw A. Wach, Alicja K. Olejnik, Joanna Dzierzawska, Janusz M. RosiakAbstract:Poly(l-lactic acid) (PLLA) and in-house synthesized poly(trimethylene carbonate) (PTMC) were used for development of Nerve Guidance tubes for support of peripheral nervous system regeneration after an injury. Phase separation of a viscous solution of the polymer mixture on a rod in a non-solvent resulted in fabrication of tubular structure of large porosity. After radiation sterilization by electron beam (EB) applied to assure safety of the product, tensile properties and elasticity of manufactured tubes were sufficient for proposed application. Influence of in vitro hydrolytic degradation on molecular weight, thermal properties of the polymers, morphology and mechanical properties of the tubes was evaluated. Besides minor mass loss in the course of 12 months hydrolytic degradation, molecular weight of PLLA component decreased steadily due to hydrolysis of ester bonds. Consequently changes in thermal properties of the polymers such as change in glass transition and melting temperatures were identified. Admixture of methyl cellulose (MC) to PLLA and PTMC synthetic polymers resulted in slight change of mechanical performance of the Channels after an initial two weeks of degradation since this water-soluble polymer of natural origin was extracted from the synthetic polymer matrix. Other parameters of the tube and those of synthetic polymers were not affected by the presence of MC. Based on the experimental data, it is confirmed that proposed polymeric material of PLLA/PTMC blend with and without addition of MC is suitable for further biological and in vivo study.
