Project related news and papers

Project related news and papers (80)

Neural interfaces with the peripheral nervous system have been developed to provide a direct communication pathway between peripheral nerves and prosthetic limbs. This study reports a regenerated peripheral nervous system which can control the reinnervated muscles and interpret neurological signals. The acquired bioelectrical signals can be used for the interpretation of mind which will be used to monitor prosthetic limbs. Transected nerves were regenerated through PDMS scaffolds and transferred signals through embedded microwires and acquisition systems.

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In this study, the in vitro release of proteins from novel, biodegradable phase-separated poly(ε-caprolactone-PEG)-block-poly(ε-caprolactone), [PCL-PEG]-b-[PCL]) multiblock copolymers with different block ratios and with a low melting temperature (49–55 °C) was studied. The effect of block ratio and PEG content of the polymers (i.e. 22.5, 37.5 and 52.5 wt%) as well as the effect of protein molecular weight (1.2, 5.8, 14, 29 and 66 kDa being goserelin, insulin, lysozyme, carbonic anhydrase and albumin, respectively) on protein release was investigated. Proteins were spray-dried with inulin as stabilizer to obtain a powder of uniform particle size. Spray-dried inulin-stabilized proteins were incorporated into polymeric implants by hot melt extrusion. All incorporated proteins fully preserved their structural integrity as determined after extraction of these proteins from the polymeric implants. In general, it was found that the release rate of the protein increased with decreasing molecular weight of the protein and with increasing the PEG content of the polymer. Swelling and degradation rate of the copolymer increased with increasing PEG content. Hence, release of proteins of various molecular weights from [PCL-PEG]-b-[PCL] multi-block copolymers can be tailored by varying the PEG content of the polymer.

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Nerve guide scaffolds from block polyurethanes without any additional growth factors or protein were prepared using a particle leaching method. The scaffolds of block polyurethanes (abbreviated as PUCL-ran-EG) based on poly(ɛ-caprolactone) (PCL-diol) and poly(ethylene glycol) (PEG) possess highly surface-area porous for cell attachment, and can provide biochemical and topographic cues to enhance tissue regeneration. The nerve guide scaffolds have pore size 1–5 μm and porosity 88%. Mechanical tests showed that the polyurethane nerve guide scaffolds have maximum loads of 4.98 ± 0.35 N and maximum stresses of 6.372 ± 0.5 MPa. The histocompatibility efficacy of these nerve guide scaffolds was tested in a rat model for peripheral nerve injury treatment. Four types of guides including PUCL-ran-EG scaffolds, autograft, PCL scaffolds and silicone tubes were compared in the rat model. After 14 weeks, bridging of a 10 mm defect gap by the regenerated nerve was observed in all rats. The nerve regeneration was systematically characterized by sciatic function index (SFI), histological assessment including HE staining, immunohistochemistry, ammonia silver staining, Masson's trichrome staining and TEM observation. Results revealed that polyurethane nerve guide scaffolds exhibit much better regeneration behavior than PCL, silicone tube groups and comparable to autograft. Electrophysiological recovery was also seen in 36%, 76%, and 87% of rats in the PCL, PUCL-ran-EG, and autograft groups respectively, whilst 29.8% was observed in the silicone tube groups. Biodegradation in vitro and in vivo show proper degradation of the PUCL-ran-EG nerve guide scaffolds. This study has demonstrated that without further modification, plain PUCL-ran-EG nerve guide scaffolds can help peripheral nerve regeneration excellently.

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Co-polymers of lactide and glycolide, referred to as PLGA, have generated tremendous interest because of their excellent biocompatibility, biodegradability and mechanical strength. Various polymeric devices like  microspheres, micro capsules, nanoparticles, pellets, implants, and films have been fabricated using these polymers. They can be transformed by spinning into filaments for subsequent fabrication of desirable textile  structures. Spinning may be accomplished by various routes. The fibers may be fabricated into various forms and may be used for implants and other surgical applications such as sutures. They are also easy to formulate into various delivery systems for carrying a variety of drug classes. The present article presents a review on the production of PLGA fiber by various methods, along with correlations between structure and  properties of the fibers. The applications of these fibers in biomedical domains are also discussed. 
 

Nerve injuries may occur due to trauma, tumor removal, and accidental surgical resection. Rodents are the most common pre-clinical nerve defect models; however, accelerated regeneration of the damaged peripheral nerves in rodents and inability to investigate large gaps are major limitations for the rodent model, making large animal models necessary. The purpose of this project is to identify key considerations in developing a non-human primate (NHP) large-gap peripheral nerve model, as well as to provide an interim analysis of our first set of NHPs.

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Peripheral nerve regeneration can be enhanced by chemical and mechanical cues for neurite growth. Aligned and randomly oriented electrospun nanofibers of poly(ε-caprolactone) (PCL) or a blend of PCL and elastin were fabricated to test their potential to provide contact guidance to embryonic chick dorsal root ganglia for peripheral nerve regeneration. Scanning electron microscopy was used to analyze the fiber diameter. Fiber diameter was found to be significantly smaller when elastin was incorporated into the scaffold (934 ± 58 nm for PCL and 519 ± 36 nm for PCL:elastin). After 24 h in culture, there was preferential cell attachment and neurite extension along the fibers of the elastin-containing scaffolds (average neurite extension 173.4 ± 20.7 μm), indicating that the presence of elastin promotes neurite outgrowth on electrospun scaffolds.

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(Nanowerk News) Damage to the peripheral nervous system, usually caused by serious accidents, can lead to loss of motor control and sensory perception. This is a very serious injury with grave consequences for the lives of thousands of people of all ages. Peripheral nerve injuries are responsible for over a million medical consultations every year in the USA and Europe, of which over 10% end up in the operating theatre. The physical impairments resulting from this injury are caused by the lack of connections between the nerve cells owing to the severing of the nerve.

Last year the Basque cooperative centre for research into microtechnologies, CIC microGUNE, took part in 15 European projects which involved a total budget of 64.5 million euros. Moreover, the centre has led four European microtechnology projects: NEURIMP, HINMICO, ANGELAB and LABONFOIL. Apart from the last one, terminated in 2013, all are currently active.

The NEURIMP project, for example, aims to develop new biomaterials which, in combination with micro-nano-fabrication technologies, enable producing prostheses that help in the repair of peripheral nerves in medullary lesions. The HINMICO initiative aims to develop and integrate diverse microtechnologies focused on achieving large-scale production of chain polymers for multi-material and multifunctional micro-components.

The other two projects led by microGUNE involve human health. The goal of ANGELAB is to develop a family of products capable of undertaking the genetic analysis of the foetus using a sample of maternal blood. The LABONFOIL project, concluded in 2013, developed four devices for rapid and low-cost diagnosis with different uses such as the monitoring of colorectal cancer or identifying pathogens in food.Over the coming years the perspectives for growth of the microsystems are in the order of 9% in sectors related to mobility, and 20% in sectors involving life sciences (human, animal and environmental health).

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Injury to peripheral nerves can occur as a result of various surgical procedures, including oral and maxillofacial surgery. In the case of nerve transaction, the gold standard treatment is the end-to-end reconnection of the two nerve stumps. When it cannot be performed, the actual strategies consist of the positioning of a nerve graft between the two stumps. Guided nerve regeneration using nano-structured scaffolds is a promising strategy to promote axon regeneration. Biodegradable electrospun conduits composed of aligned nanofibers is a new class of devices used to improve neurite extension and axon outgrowth. Self assembled peptide nanofibrous scaffolds (SAPNSs) demonstrated promising results in animal models for central nervous system injuries, and, more recently, for peripheral nerve injury. Aims of this work are (1) to review electrospun and self-assembled nanofibrous scaffolds use in vitro and in vivo for peripheral nerve regeneration; and (2) its application in peripheral nerve injuries treatment. The review focused on nanofibrous scaffolds with a diameter of less than approximately 250 nm. The conjugation in a nano scale of a natural bioactive factor with a resorbable synthetic or natural material may represent the best compromise providing both biological and mechanical cues for guided nerve regeneration. Injured peripheral nerves, such as trigeminal and facial, may benefit from these treatments.

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Gelatin-Modified Nanofibrous PHBV Tube as Artificial Nerve Graft for Rat Sciatic Nerve Regeneration

A modified nanofibrous poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nerve conduit has been used to evaluate its efficiency based on the promotion of peripheral nerve regeneration in rats. The authors used a gelatin-modified nanofibrous poly (3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit to bridge a 30 mm long gap in the rat sciatic nerve. At four months after nerve conduit implantation, regenerated nerves were macroscopically observed and histologically assessed. In the nanofibrous graft, the rat sciatic nerve trunk had been reconstructed by restoration of nerve continuity and formation of myelinated nerve fiber. There were Schwann cells and glial cells in the regenerated nerves. These findings suggest that modified nanofibrous poly(3-hydroxybutyrate-co-3- hydroxyvalerate) nerve conduit is suitable for repair of long-segment sciatic nerve defects.

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