Electrodes coated with the conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT) possess a... more Electrodes coated with the conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT) possess attractive electrochemical properties for stimulation or recording in the nervous system. Biomolecules, added as counter ions in electropolymerization, could further improve the biomaterial properties, eliminating the need for surfactant counter ions in the process. Such PEDOT/biomolecular composites, using heparin or hyaluronic acid, have previously been investigated electrochemically. In the present study, their biocompatibility is evaluated. An agarose overlay assay using L929 fibroblasts, and elution and direct contact tests on human neuroblastoma SH-SY5Y cells are applied to investigate cytotoxicity in vitro. PEDOT:heparin was further evaluated in vivo through polymer-coated implants in rodent cortex. No cytotoxic response was seen to any of the PEDOT materials tested. The examination of cortical tissue exposed to polymer-coated implants showed extensive glial scarring irrespective of implant material (Pt:polymer or Pt). However, quantification of immunological response, through distance measurements from implant site to closest neuron and counting of ED1+ cell density around implant, was comparable to those of platinum controls. These results indicate that PEDOT:heparin surfaces were non-cytotoxic and show no marked difference in immunological response in cortical tissue compared to pure platinum controls.
Electrodes of the conjugated polymer poly(3,4-ethylene dioxythiophene) (PEDOT) have been shown to... more Electrodes of the conjugated polymer poly(3,4-ethylene dioxythiophene) (PEDOT) have been shown to possess very attractive electrochemical properties for functional electrical stimulation (FES) or r ...
Sensorineural hearing loss, caused by the degeneration of inner ear sensory hair cells or afferen... more Sensorineural hearing loss, caused by the degeneration of inner ear sensory hair cells or afferent auditory neurons, is a major problem in clinical medicine. In birds and lower vertebrates, regeneration of these cells may occur but in mammals, the loss is irreversible. In this study, neuronal progenitors were derived from human embryonic stem cells in the form of neural tube-like rosettes and harvested enzymatically after 4 days (NS4), 7 days (NS7) or 11 days (NS11). This was followed by a further differentiation on laminin-coated plates for 1 or 3 weeks in neural induction medium without bFGF. Such cultures were all dominated by cells immunoreactive for nestin, a common neuronal progenitor marker, as well as for Tuj1, an early marker for neurons. Among the combinations tested, the NS7 + 1 week protocol showed the most abundant induction of the sensory neuron markers TrkC (20%) and peripherin (11%), making this protocol the most favorable for the induction of sensory neurons. Compar...
Our current knowledge of how human tissues grow and develop is limited. We need to increase our u... more Our current knowledge of how human tissues grow and develop is limited. We need to increase our understanding of tissue formation if we are to fully realize the potential of stem cells as a source of material for research into health and disease and possible therapeutic applications. Transplanted pluripotent human embryonic stem cells (hESCs) provide a potential system to model and investigate cell differentiation in humans. hESCs transplanted into immune-deficient mice form complex teratomas consisting of a range of differentiated somatic tissues, some of which appear highly organized and resemble structures normally identified in the embryo and adult. Analysis of such tumors may provide a unique opportunity to study organogenesis and lead to novel approaches in bioengineering and the growth of functioning structures composed of a range of alternative cell types. However, little has been done to characterize the developmental potential of hESCs after transplantation. This concise r...
In vitro studies have shown that the Alzheimer’s disease-related presenilin-1 protein can mediate... more In vitro studies have shown that the Alzheimer’s disease-related presenilin-1 protein can mediate Notch-1 receptor cleavage during signalling. In the present study, we compared the distribution of presenilin-1 and Notch-1 receptor immunoreactivities in human embryonic CNS tissue during the first trimester of development. Our aim was to gain insight into whether these proteins are likely to interact functionally during human
Electrodes coated with the conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT) possess a... more Electrodes coated with the conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT) possess attractive electrochemical properties for stimulation or recording in the nervous system. Biomolecules, added as counter ions in electropolymerization, could further improve the biomaterial properties, eliminating the need for surfactant counter ions in the process. Such PEDOT/biomolecular composites, using heparin or hyaluronic acid, have previously been investigated electrochemically. In the present study, their biocompatibility is evaluated. An agarose overlay assay using L929 fibroblasts, and elution and direct contact tests on human neuroblastoma SH-SY5Y cells are applied to investigate cytotoxicity in vitro. PEDOT:heparin was further evaluated in vivo through polymer-coated implants in rodent cortex. No cytotoxic response was seen to any of the PEDOT materials tested. The examination of cortical tissue exposed to polymer-coated implants showed extensive glial scarring irrespective of implant material (Pt:polymer or Pt). However, quantification of immunological response, through distance measurements from implant site to closest neuron and counting of ED1+ cell density around implant, was comparable to those of platinum controls. These results indicate that PEDOT:heparin surfaces were non-cytotoxic and show no marked difference in immunological response in cortical tissue compared to pure platinum controls.
Electrodes of the conjugated polymer poly(3,4-ethylene dioxythiophene) (PEDOT) have been shown to... more Electrodes of the conjugated polymer poly(3,4-ethylene dioxythiophene) (PEDOT) have been shown to possess very attractive electrochemical properties for functional electrical stimulation (FES) or r ...
Sensorineural hearing loss, caused by the degeneration of inner ear sensory hair cells or afferen... more Sensorineural hearing loss, caused by the degeneration of inner ear sensory hair cells or afferent auditory neurons, is a major problem in clinical medicine. In birds and lower vertebrates, regeneration of these cells may occur but in mammals, the loss is irreversible. In this study, neuronal progenitors were derived from human embryonic stem cells in the form of neural tube-like rosettes and harvested enzymatically after 4 days (NS4), 7 days (NS7) or 11 days (NS11). This was followed by a further differentiation on laminin-coated plates for 1 or 3 weeks in neural induction medium without bFGF. Such cultures were all dominated by cells immunoreactive for nestin, a common neuronal progenitor marker, as well as for Tuj1, an early marker for neurons. Among the combinations tested, the NS7 + 1 week protocol showed the most abundant induction of the sensory neuron markers TrkC (20%) and peripherin (11%), making this protocol the most favorable for the induction of sensory neurons. Compar...
Our current knowledge of how human tissues grow and develop is limited. We need to increase our u... more Our current knowledge of how human tissues grow and develop is limited. We need to increase our understanding of tissue formation if we are to fully realize the potential of stem cells as a source of material for research into health and disease and possible therapeutic applications. Transplanted pluripotent human embryonic stem cells (hESCs) provide a potential system to model and investigate cell differentiation in humans. hESCs transplanted into immune-deficient mice form complex teratomas consisting of a range of differentiated somatic tissues, some of which appear highly organized and resemble structures normally identified in the embryo and adult. Analysis of such tumors may provide a unique opportunity to study organogenesis and lead to novel approaches in bioengineering and the growth of functioning structures composed of a range of alternative cell types. However, little has been done to characterize the developmental potential of hESCs after transplantation. This concise r...
In vitro studies have shown that the Alzheimer’s disease-related presenilin-1 protein can mediate... more In vitro studies have shown that the Alzheimer’s disease-related presenilin-1 protein can mediate Notch-1 receptor cleavage during signalling. In the present study, we compared the distribution of presenilin-1 and Notch-1 receptor immunoreactivities in human embryonic CNS tissue during the first trimester of development. Our aim was to gain insight into whether these proteins are likely to interact functionally during human
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