Collagen protein is an ideal scaffold material for the transplantation of neural stem cells. In this study rat neural stern cells were seeded into a three-dimensional collagen gel scaffold, with suspension cultured ne...Collagen protein is an ideal scaffold material for the transplantation of neural stem cells. In this study rat neural stern cells were seeded into a three-dimensional collagen gel scaffold, with suspension cultured neural stem cells being used as a control group. Neural stem cells, which were cultured in medium containing epidermal growth factor and basic fibroblast growth factor, actively expanded and formed neurospheres in both culture groups. In serum-free medium conditions, the processes extended from neurospheres in the collagen gel group were much longer than those in the suspension culture group. Immunofluorescence staining showed that neurespheres cultured in collagen gels were stained positive for nestin and differentiated cells were stained positive for the neuronal marker βIII-tubulin, the astrocytic marker glial fibrillary acidic protein and the oligodendrocytic marker 2＇,3＇-cyclic nucleotide 3＇-phosphodiesterase. Compared with neurospheres cultured in suspension, the differentiation potential of neural stem cells cultured in collagen gels increased, with the formation of neurons at an early stage. Our results show that the three-dimensional collagen gel culture system is superior to suspension culture in the proliferation, differentiation and process outgrowth of neural stem cells.展开更多
The electrodes of a cochlear implant are located far from the surviving neurons of the spiral ganglion, which results in decreased precision of neural activation compared to the normal ear. If the neurons could be ind...The electrodes of a cochlear implant are located far from the surviving neurons of the spiral ganglion, which results in decreased precision of neural activation compared to the normal ear. If the neurons could be induced to extend neurites toward the implant, it might be possible to stimulate more discrete subpopulations of neurons, and to increase the resolution of the device. However, a major barrier to neurite growth toward a cochlear implant is the fluid filling the scala tympani, which separates the neurons from the electrodes. The goal of this study was to evaluate the growth of cochlear neurites in three-dimensional extracellular matrix molecule gels, and to increase biocompatibility by using fibroblasts stably transfected to produce neurotrophin-3 and brain-derived neurotrophic factor. Spiral ganglion explants from neonatal rats were evaluated in cultures. They were exposed to soluble neurotrophins, cells transfected to secrete neurotrophins, and/or collagen gels. We found that cochlear neurites grew readily on collagen surfaces and in three-dimensional collagen gels. Co-culture with cells producing neurotrophin-3 resulted in increased numbers of neurites, and neurites that were longer than when explants were cultured with control fibroblasts stably transfected with green fluorescent protein. Brain-derived neurotrophic factor-producing cells resulted in a more dramatic increase in the number of neurites, but there was no significant effect on neurite length. It is suggested that extracellular matrix molecule gels and cells transfected to produce neurotrophins offer an opportunity to attract spiral ganglion neurites toward a cochlear implant.展开更多
Background： Endothelium allotransplantation is the primary treatment for corneal decompensation. The worldwide shortage of donor corneal tissue has led to increasing pressure to seek an alternative for surgical resto...Background： Endothelium allotransplantation is the primary treatment for corneal decompensation. The worldwide shortage of donor corneal tissue has led to increasing pressure to seek an alternative for surgical restoration of corneal endothelium. Compressed collagen （CC） gels have excellent biocompatibility, simple preparation course and easy to be manipulated. This study aimed to form a new biomimetic endothelium graft by CC. Methods： We expanded bovine corneal endothelial cells （B-CECs） on laminin-coated CC to form a biomimetic endothelium graft. Scanning electron microscope was used for ultrastructural analysis and tight junction protein ZO-1 expression was tested by immunohistochemistry. Results： The biomimetic endothelium graft, we conducted had normal cell morphology, ultrastructure and higher cell density （3612.2 ±43.4 cells/mm2）. ZO-1 localization at B-CECs membrane indicated the bioengineered grail possess the basic endothelium function. Conclusions： A biomimetic endothelium graft with B-CECs expanded on CC sheet was constructed, which possessed cells＇ morphology similar to that of in vivo endothelial cells and specific basic function ofendothelium layer. This method provided the possibility of using one donor＇s cornea to form multiple uniformed endothelium grafts so as to overcome the shortage ofcadaveric cornea tissue.展开更多
The two waves period of the COVID-19 pandemic saw the use of hydro- alcoholic gel and the consumption of capsules containing improved traditional remedies. At one point, there was a stock-out and a price increase...The two waves period of the COVID-19 pandemic saw the use of hydro- alcoholic gel and the consumption of capsules containing improved traditional remedies. At one point, there was a stock-out and a price increase forthese products. Furthermore, in the food industry, the catering industry adopts gelatin in its current practice. Pig gelatin dominates the international market. And for some religious practices, pork is forbidden and yet these people consume them without taking notice. The production of gelatin from broiler feet seems economically viable because broiler feet are considered slaughterhouse waste that is sold at very low prices. The poultry industry has seen an increase in broiler farming over the last twenty years. However, the latter has all the characteristics required for the production of gelatin. It will therefore comply with the standards of use described in the international codex oenological for gelatins. Physical and chemical analyses such as, ash content, moisture content, and pH measurements were done for the extracted gelatins. Sensible elements are checked with ED XRF spectroscopy. All the results were good and showed without any doubt that broiler gelatin is edible.展开更多
AIM: To investigate diffusion in mammalian cell culture by gel entrapment within hollow fibers.METHODS: Freshly isolated rat hepatocytes or human oral epidermoid carcinoma (KB) cells were entrapped in type Ⅰ collagen...AIM: To investigate diffusion in mammalian cell culture by gel entrapment within hollow fibers.METHODS: Freshly isolated rat hepatocytes or human oral epidermoid carcinoma (KB) cells were entrapped in type Ⅰ collagen solutions and statically cultured inside microporous and ultrafiltration hollow fibers. During the culture time collagen gel contraction, cell viability and specific function were assessed. Effective diffusion coefficients of glucose in cell-matrix gels were determined by lag time analysis in a diffusion cell.R ESULTS: Significant gel contractions occurred in the collagen gels by entrapment of either viable hepatocytes or KB cells. And the gel contraction caused a significant reduction on effective diffusion coefficient of glucose. The cell viability assay of both hepatocytes and KB cells statically cultured in hollow fibers by collagen entrapment further confirmed the existence of the inhibited mass transfer by diffusion. Urea was secreted about 50% more by hepatocytes entrapped in hollow fibers with pore size of 0.1 pm than that in hollow fibers with MWCO of 100 ku.CONCLUSION: Cell-matrix gel and membrane pore size are the two factors relevant to the limited mass transfer by diffusion in such gel entrapment of mammalian cell culture.展开更多
The porous scaffold of the sol-gel derived bioactive glass （BG） in the system CaO-P2O5-SiO2 was treated with the type Ⅰ collagen solution. The pore walls of the scaffold were covered by the collagenous network. The...The porous scaffold of the sol-gel derived bioactive glass （BG） in the system CaO-P2O5-SiO2 was treated with the type Ⅰ collagen solution. The pore walls of the scaffold were covered by the collagenous network. The in vitro mineralization behavior of the sol- gel derived bioglassl collegen composite porous scaffold was investigated by immersion in supersaturated calcification solution （ SCS ） at 37℃ for different times, XRD , FTIR, SEM/ EDAX techniques were applied to analyze the crystalline phases, morphology and composition of the minerals formed on the pore walls of the scaffold. It was found that with increasing of immersion time, the morphology of reaction products on the pore walls changed from the spherical particles of calcium phosphate to the flake-like HCA crystals.展开更多
文摘Collagen protein is an ideal scaffold material for the transplantation of neural stem cells. In this study rat neural stern cells were seeded into a three-dimensional collagen gel scaffold, with suspension cultured neural stem cells being used as a control group. Neural stem cells, which were cultured in medium containing epidermal growth factor and basic fibroblast growth factor, actively expanded and formed neurospheres in both culture groups. In serum-free medium conditions, the processes extended from neurospheres in the collagen gel group were much longer than those in the suspension culture group. Immunofluorescence staining showed that neurespheres cultured in collagen gels were stained positive for nestin and differentiated cells were stained positive for the neuronal marker βIII-tubulin, the astrocytic marker glial fibrillary acidic protein and the oligodendrocytic marker 2＇,3＇-cyclic nucleotide 3＇-phosphodiesterase. Compared with neurospheres cultured in suspension, the differentiation potential of neural stem cells cultured in collagen gels increased, with the formation of neurons at an early stage. Our results show that the three-dimensional collagen gel culture system is superior to suspension culture in the proliferation, differentiation and process outgrowth of neural stem cells.
基金supported by grants from the Research Service of the United States Veterans Administration (to Allen Frederic Ryan and Stephen Fausti)the National Institute of Health/National Institute on Deafness and Other Communication Disorders (to Allen Frederic Ryan)+2 种基金the National Institute of Health Summer Research Program (to Joanna Xie)the Deafness Research Foundation (to Lina Mullen)the National Organization for Hearing Research (to Lina Mullen)
文摘The electrodes of a cochlear implant are located far from the surviving neurons of the spiral ganglion, which results in decreased precision of neural activation compared to the normal ear. If the neurons could be induced to extend neurites toward the implant, it might be possible to stimulate more discrete subpopulations of neurons, and to increase the resolution of the device. However, a major barrier to neurite growth toward a cochlear implant is the fluid filling the scala tympani, which separates the neurons from the electrodes. The goal of this study was to evaluate the growth of cochlear neurites in three-dimensional extracellular matrix molecule gels, and to increase biocompatibility by using fibroblasts stably transfected to produce neurotrophin-3 and brain-derived neurotrophic factor. Spiral ganglion explants from neonatal rats were evaluated in cultures. They were exposed to soluble neurotrophins, cells transfected to secrete neurotrophins, and/or collagen gels. We found that cochlear neurites grew readily on collagen surfaces and in three-dimensional collagen gels. Co-culture with cells producing neurotrophin-3 resulted in increased numbers of neurites, and neurites that were longer than when explants were cultured with control fibroblasts stably transfected with green fluorescent protein. Brain-derived neurotrophic factor-producing cells resulted in a more dramatic increase in the number of neurites, but there was no significant effect on neurite length. It is suggested that extracellular matrix molecule gels and cells transfected to produce neurotrophins offer an opportunity to attract spiral ganglion neurites toward a cochlear implant.
文摘Background： Endothelium allotransplantation is the primary treatment for corneal decompensation. The worldwide shortage of donor corneal tissue has led to increasing pressure to seek an alternative for surgical restoration of corneal endothelium. Compressed collagen （CC） gels have excellent biocompatibility, simple preparation course and easy to be manipulated. This study aimed to form a new biomimetic endothelium graft by CC. Methods： We expanded bovine corneal endothelial cells （B-CECs） on laminin-coated CC to form a biomimetic endothelium graft. Scanning electron microscope was used for ultrastructural analysis and tight junction protein ZO-1 expression was tested by immunohistochemistry. Results： The biomimetic endothelium graft, we conducted had normal cell morphology, ultrastructure and higher cell density （3612.2 ±43.4 cells/mm2）. ZO-1 localization at B-CECs membrane indicated the bioengineered grail possess the basic endothelium function. Conclusions： A biomimetic endothelium graft with B-CECs expanded on CC sheet was constructed, which possessed cells＇ morphology similar to that of in vivo endothelial cells and specific basic function ofendothelium layer. This method provided the possibility of using one donor＇s cornea to form multiple uniformed endothelium grafts so as to overcome the shortage ofcadaveric cornea tissue.
文摘The two waves period of the COVID-19 pandemic saw the use of hydro- alcoholic gel and the consumption of capsules containing improved traditional remedies. At one point, there was a stock-out and a price increase forthese products. Furthermore, in the food industry, the catering industry adopts gelatin in its current practice. Pig gelatin dominates the international market. And for some religious practices, pork is forbidden and yet these people consume them without taking notice. The production of gelatin from broiler feet seems economically viable because broiler feet are considered slaughterhouse waste that is sold at very low prices. The poultry industry has seen an increase in broiler farming over the last twenty years. However, the latter has all the characteristics required for the production of gelatin. It will therefore comply with the standards of use described in the international codex oenological for gelatins. Physical and chemical analyses such as, ash content, moisture content, and pH measurements were done for the extracted gelatins. Sensible elements are checked with ED XRF spectroscopy. All the results were good and showed without any doubt that broiler gelatin is edible.
基金Supported by the National Natural Science Foundation of China,No.90209053Zhejiang Scientific Project, No. 2003C31042
文摘AIM: To investigate diffusion in mammalian cell culture by gel entrapment within hollow fibers.METHODS: Freshly isolated rat hepatocytes or human oral epidermoid carcinoma (KB) cells were entrapped in type Ⅰ collagen solutions and statically cultured inside microporous and ultrafiltration hollow fibers. During the culture time collagen gel contraction, cell viability and specific function were assessed. Effective diffusion coefficients of glucose in cell-matrix gels were determined by lag time analysis in a diffusion cell.R ESULTS: Significant gel contractions occurred in the collagen gels by entrapment of either viable hepatocytes or KB cells. And the gel contraction caused a significant reduction on effective diffusion coefficient of glucose. The cell viability assay of both hepatocytes and KB cells statically cultured in hollow fibers by collagen entrapment further confirmed the existence of the inhibited mass transfer by diffusion. Urea was secreted about 50% more by hepatocytes entrapped in hollow fibers with pore size of 0.1 pm than that in hollow fibers with MWCO of 100 ku.CONCLUSION: Cell-matrix gel and membrane pore size are the two factors relevant to the limited mass transfer by diffusion in such gel entrapment of mammalian cell culture.
文摘The porous scaffold of the sol-gel derived bioactive glass （BG） in the system CaO-P2O5-SiO2 was treated with the type Ⅰ collagen solution. The pore walls of the scaffold were covered by the collagenous network. The in vitro mineralization behavior of the sol- gel derived bioglassl collegen composite porous scaffold was investigated by immersion in supersaturated calcification solution （ SCS ） at 37℃ for different times, XRD , FTIR, SEM/ EDAX techniques were applied to analyze the crystalline phases, morphology and composition of the minerals formed on the pore walls of the scaffold. It was found that with increasing of immersion time, the morphology of reaction products on the pore walls changed from the spherical particles of calcium phosphate to the flake-like HCA crystals.
