Three dimensional（3D） bioprinting, which involves depositing bioinks（mixed biomaterials） layer by layer to form computer-aided designs, is an ideal method for fabricating complex 3D biological structures. However,...Three dimensional（3D） bioprinting, which involves depositing bioinks（mixed biomaterials） layer by layer to form computer-aided designs, is an ideal method for fabricating complex 3D biological structures. However, it remains challenging to prepare biomaterials with micro-nanostructures that accurately mimic the nanostructural features of natural tissues. A novel nanotechnological tool, electrospinning, permits the processing and modification of proper nanoscale biomaterials to enhance neural cell adhesion, migration, proliferation, differentiation, and subsequent nerve regeneration. The composite scaffold was prepared by combining 3D bioprinting with subsequent electrochemical deposition of polypyrrole and electrospinning of silk fibroin to form a composite polypyrrole/silk fibroin scaffold. Fourier transform infrared spectroscopy was used to analyze scaffold composition. The surface morphology of the scaffold was observed by light microscopy and scanning electron microscopy. A digital multimeter was used to measure the resistivity of prepared scaffolds. Light microscopy was applied to observe the surface morphology of scaffolds immersed in water or Dulbecco＇s Modified Eagle＇s Medium at 37℃ for 30 days to assess stability. Results showed characteristic peaks of polypyrrole and silk fibroin in the synthesized conductive polypyrrole/silk fibroin scaffold, as well as the structure of the electrospun nanofiber layer on the surface. The electrical conductivity was 1 × 10^-5–1 × 10^-3 S/cm, while stability was 66.67%. A 3-（4,5-dimethyl-2-thiazolyl）-2,5-diphenyl-2-H-tetrazolium bromide assay was employed to measure scaffold cytotoxicity in vitro. Fluorescence microscopy was used to observe Ed U-labeled Schwann cells to quantify cell proliferation. Immunohistochemistry was utilized to detect S100β immunoreactivity, while scanning electron microscopy was applied to observe the morphology of adherent Schwann cells. Results demonstrated that the polypyrrole/silk fibroin scaffold was not cytotoxic and did not affect Schwann cell proliferation. Moreover, filopodia formed on the scaffold and Schwann cells were regularly arranged. Our findings verified that the composite polypyrrole/silk fibroin scaffold has good biocompatibility and may be a suitable material for neural tissue engineering.展开更多
Rhizoma Coptidis （RC）, a widely used traditional Chinese medicine, is commonly believed to be non-toxic. However, little is known about its cytotoxicity and relevant mechanisms at cellular and genetic levels. The pr...Rhizoma Coptidis （RC）, a widely used traditional Chinese medicine, is commonly believed to be non-toxic. However, little is known about its cytotoxicity and relevant mechanisms at cellular and genetic levels. The present study aimed to explore the cytotoxicity of RC and its possible mechanisms related to cell cycle arrest, DNA damage and reactive oxygen species （ROS） level in L929 murine fibroblast cells. The cells were cultured in vitro and treated with different RC concentrations for 24 h. Cell viability was determined by CCK-8 method, morphological changes were observed with an inverted microscope, cell cycle and ROS level were examined by flow cytometry, and DNA damages were detected by comet assay. Our results showed that cell viability was significantly decreased in a dose-dependent manner when the RC concentration was higher than 1 mg/mL. ARC concentration above 1 mg/mL altered the morphology of L929 cells. Both cells at G2/M phase and the ROS level increased in the 2 mg/mL group. Each DNA damage indicator score increased in the groups with the RC concentration of above 0.05 mg/mL. Taken together, our study suggested that RC at a high dosage exhibited cytotoxicity on L929 cells, which was likely to be the consequences of cell cycle arrest, DNA damage and accumulation of intracellular ROS.展开更多
Recombinant eucaryotic expression vector pLXSN/s-bcl-2 has been constructed by cloning human bcl-2 cDNA containing the full-length open reading frame into the vector pLXSN in sense orientation, and a mammalian cell mo...Recombinant eucaryotic expression vector pLXSN/s-bcl-2 has been constructed by cloning human bcl-2 cDNA containing the full-length open reading frame into the vector pLXSN in sense orientation, and a mammalian cell model expressing human bcl-2 protein has been established by electroporating the recombinant vector into mouse L929 cells. bcl-2 expression in L929 cells has no effect on the cell growth and survival under normal culture conditions, but it can enhance the survival of the cell in the challenge of some apoptosis-inducing stimuli, including tumor necrosis factor α(TNF α) and staurosporine (STS).展开更多
基金supported by the National Natural Science Foundation of China,No.81671823,81701835a grant from the National Key Research and Development Program of China,No.2016YFC1101603a grant from the Natural Science Research Program of Nantong of China,No.MS12016056
文摘Three dimensional（3D） bioprinting, which involves depositing bioinks（mixed biomaterials） layer by layer to form computer-aided designs, is an ideal method for fabricating complex 3D biological structures. However, it remains challenging to prepare biomaterials with micro-nanostructures that accurately mimic the nanostructural features of natural tissues. A novel nanotechnological tool, electrospinning, permits the processing and modification of proper nanoscale biomaterials to enhance neural cell adhesion, migration, proliferation, differentiation, and subsequent nerve regeneration. The composite scaffold was prepared by combining 3D bioprinting with subsequent electrochemical deposition of polypyrrole and electrospinning of silk fibroin to form a composite polypyrrole/silk fibroin scaffold. Fourier transform infrared spectroscopy was used to analyze scaffold composition. The surface morphology of the scaffold was observed by light microscopy and scanning electron microscopy. A digital multimeter was used to measure the resistivity of prepared scaffolds. Light microscopy was applied to observe the surface morphology of scaffolds immersed in water or Dulbecco＇s Modified Eagle＇s Medium at 37℃ for 30 days to assess stability. Results showed characteristic peaks of polypyrrole and silk fibroin in the synthesized conductive polypyrrole/silk fibroin scaffold, as well as the structure of the electrospun nanofiber layer on the surface. The electrical conductivity was 1 × 10^-5–1 × 10^-3 S/cm, while stability was 66.67%. A 3-（4,5-dimethyl-2-thiazolyl）-2,5-diphenyl-2-H-tetrazolium bromide assay was employed to measure scaffold cytotoxicity in vitro. Fluorescence microscopy was used to observe Ed U-labeled Schwann cells to quantify cell proliferation. Immunohistochemistry was utilized to detect S100β immunoreactivity, while scanning electron microscopy was applied to observe the morphology of adherent Schwann cells. Results demonstrated that the polypyrrole/silk fibroin scaffold was not cytotoxic and did not affect Schwann cell proliferation. Moreover, filopodia formed on the scaffold and Schwann cells were regularly arranged. Our findings verified that the composite polypyrrole/silk fibroin scaffold has good biocompatibility and may be a suitable material for neural tissue engineering.
基金National Natural Science Foundation of China(Grant No.31172358)
文摘Rhizoma Coptidis （RC）, a widely used traditional Chinese medicine, is commonly believed to be non-toxic. However, little is known about its cytotoxicity and relevant mechanisms at cellular and genetic levels. The present study aimed to explore the cytotoxicity of RC and its possible mechanisms related to cell cycle arrest, DNA damage and reactive oxygen species （ROS） level in L929 murine fibroblast cells. The cells were cultured in vitro and treated with different RC concentrations for 24 h. Cell viability was determined by CCK-8 method, morphological changes were observed with an inverted microscope, cell cycle and ROS level were examined by flow cytometry, and DNA damages were detected by comet assay. Our results showed that cell viability was significantly decreased in a dose-dependent manner when the RC concentration was higher than 1 mg/mL. ARC concentration above 1 mg/mL altered the morphology of L929 cells. Both cells at G2/M phase and the ROS level increased in the 2 mg/mL group. Each DNA damage indicator score increased in the groups with the RC concentration of above 0.05 mg/mL. Taken together, our study suggested that RC at a high dosage exhibited cytotoxicity on L929 cells, which was likely to be the consequences of cell cycle arrest, DNA damage and accumulation of intracellular ROS.
文摘Recombinant eucaryotic expression vector pLXSN/s-bcl-2 has been constructed by cloning human bcl-2 cDNA containing the full-length open reading frame into the vector pLXSN in sense orientation, and a mammalian cell model expressing human bcl-2 protein has been established by electroporating the recombinant vector into mouse L929 cells. bcl-2 expression in L929 cells has no effect on the cell growth and survival under normal culture conditions, but it can enhance the survival of the cell in the challenge of some apoptosis-inducing stimuli, including tumor necrosis factor α(TNF α) and staurosporine (STS).
