Carbon nanotube(CNT)composite materials are very attractive for use in neural tissue engineering and biosensor coatings.CNT scaffolds are excellent mimics of extracellular matrix due to their hydrophilicity,viscosity,...Carbon nanotube(CNT)composite materials are very attractive for use in neural tissue engineering and biosensor coatings.CNT scaffolds are excellent mimics of extracellular matrix due to their hydrophilicity,viscosity,and biocompatibility.CNTs can also impart conductivity to other insulating materials improve mechanical stability guide neuronal cell behavior and trigger axon regeneration.The performance of chitosan(CS)/polyethylene glycol(PEG)composite scaffolds could be optimized by introducing multi-walled CNTs(MWCNTs).CS/PEG/CNT composite scaffolds with CNT content of 1%,3%,and 5%(1%=0.01 g/mL)were prepared by freeze-drying.Their physical and chemical properties and biocompatibility were evaluated.Scanning electron microscopy(SEM)showed that the composite scaffolds had a highly connected porous structure.Transmission electron microscope(TEM)and Raman spectroscopy proved that the CNTs were well dispersed in the CS/PEG matrix and combined with the CS/PEG nanofiber bundles.MWCNTs enhanced the elastic modulus of the scaffold.The porosity of the scaffolds ranged from 83%to 96%.They reached a stable water swelling state within 24 h,and swelling decreased with increasing MWCNT concentration.The electrical conductivity and cell adhesion rate of the scaffolds increased with increasing MWCNT content.Immunofluorescence showed that rat pheochromocytoma(PC12)cells grown in the scaffolds had characteristics similar to nerve cells.We measured changes in the expression of nerve cell markers by quantitative real-time polymerase chain reaction(qRT-PCR),and found that PC12 cells cultured in the scaffolds expressed growth-associated protein 43(GAP43),nerve growth factor receptor(NGFR),and class IIIβ-tubulin(TUBB3)proteins.Preliminary research showed that the prepared CS/PEG/CNT scaffold has good biocompatibility and can be further applied to neural tissue engineering research.展开更多
A series of multiblock copolymers of PLLA\|PEG(PLE) with high molecular weight were synthesized by coupling PLLA\|PEG\|PLLA triblock copolymers with succinic anhydride in the presence of ( N,N\| dimethylamino) pyridin...A series of multiblock copolymers of PLLA\|PEG(PLE) with high molecular weight were synthesized by coupling PLLA\|PEG\|PLLA triblock copolymers with succinic anhydride in the presence of ( N,N\| dimethylamino) pyridine(DMAP) and dicyclohexylcarbodimide (DCC).The results of the viscometry measurement,GPC and 1H\|NMR,elucidated that multiblock PLE copolymers with high content of short PEG segments( M n=2000) had been successfully obtained.The crystallinity of the copolymers was investigated by X\|ray diffraction.Mechanical testing showed that multiblock copolymers had relatively high tensile strength and large elongation.In a word,the measurements showed that the multiblock PLE copolymers had high content of short PEG segments( M n=2000),high molecular weight( M w～100,000),excellent hydrophilicity and mechanical properties.The results of cells cultured on the multiblock PLE copolymer indicated that it might be suitable to be utilized as cell scaffold for tissue engineering.展开更多
Because the inhibition of Nogo proteins can promote neurite growth and nerve cell differentiation, a cell-scaffold complex seeded with Nogo receptor （NgR）-silenced neural stem cells and Schwann cells may be able to ...Because the inhibition of Nogo proteins can promote neurite growth and nerve cell differentiation, a cell-scaffold complex seeded with Nogo receptor （NgR）-silenced neural stem cells and Schwann cells may be able to improve the microenvironment for spinal cord injury repair. Previous studies have found that mild hypothermia helps to attenuate secondary damage in the spinal cord and exerts a neuroprotective effect. Here, we constructed a cell-scaffold complex consisting of a poly（D,L-lactide-co-glycolic acid） （PLGA） scaffold seeded with NgR-silenced neural stem cells and Schwann cells, and determined the effects of mild hypothermia combined with the cell-scaffold complexes on the spinal cord hemi-transection injury in the T9 segment in rats. Compared with the PLGA group and the NgR-silencing cells ＋ PLGA group, hindlimb motor function and nerve electrophysiological function were dearly improved, pathological changes in the injured spinal cord were attenuated, and the number of surviving cells and nerve fibers were increased in the group treated with the NgR-silenced cell scaffold ＋ mild hypothermia at 34℃ for 6 hours. Furthermore, fewer pathological changes to the injured spinal cord and more surviving cells and nerve fibers were found after mild hypothermia therapy than in injuries not treated with mild hypothermia. These experimental results indicate that mild hypothermia combined with NgR gene-silenced cells in a PLGA scaffold may be an effective therapy for treating spinal cord injury.展开更多
基金This study was supported by the National Natural Science Foundation of China(Nos.51975400 and 62031022)the Shanxi Provincial Key Medical Scientific Research Project(No.2020XM06),China.
文摘Carbon nanotube(CNT)composite materials are very attractive for use in neural tissue engineering and biosensor coatings.CNT scaffolds are excellent mimics of extracellular matrix due to their hydrophilicity,viscosity,and biocompatibility.CNTs can also impart conductivity to other insulating materials improve mechanical stability guide neuronal cell behavior and trigger axon regeneration.The performance of chitosan(CS)/polyethylene glycol(PEG)composite scaffolds could be optimized by introducing multi-walled CNTs(MWCNTs).CS/PEG/CNT composite scaffolds with CNT content of 1%,3%,and 5%(1%=0.01 g/mL)were prepared by freeze-drying.Their physical and chemical properties and biocompatibility were evaluated.Scanning electron microscopy(SEM)showed that the composite scaffolds had a highly connected porous structure.Transmission electron microscope(TEM)and Raman spectroscopy proved that the CNTs were well dispersed in the CS/PEG matrix and combined with the CS/PEG nanofiber bundles.MWCNTs enhanced the elastic modulus of the scaffold.The porosity of the scaffolds ranged from 83%to 96%.They reached a stable water swelling state within 24 h,and swelling decreased with increasing MWCNT concentration.The electrical conductivity and cell adhesion rate of the scaffolds increased with increasing MWCNT content.Immunofluorescence showed that rat pheochromocytoma(PC12)cells grown in the scaffolds had characteristics similar to nerve cells.We measured changes in the expression of nerve cell markers by quantitative real-time polymerase chain reaction(qRT-PCR),and found that PC12 cells cultured in the scaffolds expressed growth-associated protein 43(GAP43),nerve growth factor receptor(NGFR),and class IIIβ-tubulin(TUBB3)proteins.Preliminary research showed that the prepared CS/PEG/CNT scaffold has good biocompatibility and can be further applied to neural tissue engineering research.
文摘A series of multiblock copolymers of PLLA\|PEG(PLE) with high molecular weight were synthesized by coupling PLLA\|PEG\|PLLA triblock copolymers with succinic anhydride in the presence of ( N,N\| dimethylamino) pyridine(DMAP) and dicyclohexylcarbodimide (DCC).The results of the viscometry measurement,GPC and 1H\|NMR,elucidated that multiblock PLE copolymers with high content of short PEG segments( M n=2000) had been successfully obtained.The crystallinity of the copolymers was investigated by X\|ray diffraction.Mechanical testing showed that multiblock copolymers had relatively high tensile strength and large elongation.In a word,the measurements showed that the multiblock PLE copolymers had high content of short PEG segments( M n=2000),high molecular weight( M w～100,000),excellent hydrophilicity and mechanical properties.The results of cells cultured on the multiblock PLE copolymer indicated that it might be suitable to be utilized as cell scaffold for tissue engineering.
基金supported by a grant from the Application Basis and Front Technology Projects of Tianjin(Science and Technology Foundation of Tianjin),No.12JCYBJC18000
文摘Because the inhibition of Nogo proteins can promote neurite growth and nerve cell differentiation, a cell-scaffold complex seeded with Nogo receptor （NgR）-silenced neural stem cells and Schwann cells may be able to improve the microenvironment for spinal cord injury repair. Previous studies have found that mild hypothermia helps to attenuate secondary damage in the spinal cord and exerts a neuroprotective effect. Here, we constructed a cell-scaffold complex consisting of a poly（D,L-lactide-co-glycolic acid） （PLGA） scaffold seeded with NgR-silenced neural stem cells and Schwann cells, and determined the effects of mild hypothermia combined with the cell-scaffold complexes on the spinal cord hemi-transection injury in the T9 segment in rats. Compared with the PLGA group and the NgR-silencing cells ＋ PLGA group, hindlimb motor function and nerve electrophysiological function were dearly improved, pathological changes in the injured spinal cord were attenuated, and the number of surviving cells and nerve fibers were increased in the group treated with the NgR-silenced cell scaffold ＋ mild hypothermia at 34℃ for 6 hours. Furthermore, fewer pathological changes to the injured spinal cord and more surviving cells and nerve fibers were found after mild hypothermia therapy than in injuries not treated with mild hypothermia. These experimental results indicate that mild hypothermia combined with NgR gene-silenced cells in a PLGA scaffold may be an effective therapy for treating spinal cord injury.
