The γ/γ＇ microstructure of a Re-containing Ni-based single crystal super alloy after a two-step aging was studied using scanning electron microscopy （SEM）,transmission electron microscopy （TEM） and scanning tra...The γ/γ＇ microstructure of a Re-containing Ni-based single crystal super alloy after a two-step aging was studied using scanning electron microscopy （SEM）,transmission electron microscopy （TEM） and scanning transmission electron microscopy （STEM）.The crystals were grown by the floating zone （FZ） method.Both cuboidal and spherical γ＇ precipitates were formed after a two-step aging.The size of the cuboidal γ＇ phases first increased and then decreased with the extension of the second-step aging time.Re,Co and Cr strongly concentrated in the γ phase whereas Ni and Al enriched in the γ＇ phase.Thermodynamic calculation by JMatPro was performed to explain the experimental observations.展开更多
With the increasingly promising role of nanomaterials in tissue engineering and regenerative medicine, the interaction between stem cells and nanoparticles has become a critical focus. The entry of nanoparticles into ...With the increasingly promising role of nanomaterials in tissue engineering and regenerative medicine, the interaction between stem cells and nanoparticles has become a critical focus. The entry of nanoparticles into cells has become a primary issue for effectively regulating the subsequent safety and performance of nanomaterials in vivo. Although the influence of nanomaterials on endocytosis has been extensively studied, reports on the influence of stem cells are rare.Moreover, the effect of nanomaterials on stem cells is also dependent upon the action mode. Unfortunately, the interaction between stem cells and assembled nanoparticles is often neglected. In this paper, we explore for the first time the uptake of γ-Fe2O3 nanoparticles by adipose-derived stem cells with different passage numbers. The results demonstrate that cellular viability decreases and cell senescence level increases with the extension of the passage number. We found the surface appearance of cellular membranes to become increasingly rough and uneven with increasing passage numbers. The iron content in the dissociative nanoparticles was also significantly reduced with increases in the passage number. However, we observed multiple-passaged stem cells cultured on assembled nanoparticles to have similarly low iron content levels. The mechanism may lie in the magnetic effect of γ-Fe2O3 nanoparticles resulting from the field-directed assembly. The results of this work will facilitate the understanding and translation of nanomaterials in the clinical application of stem cells.展开更多
基金Project(08dj1400402) supported by the Major Program for the Fundamental Research of Science and Technology Committee of the Shanghai Municipality,ChinaProject(09ZZ16) supported by Innovation Program of Shanghai Municipal Education Committee,China
文摘The γ/γ＇ microstructure of a Re-containing Ni-based single crystal super alloy after a two-step aging was studied using scanning electron microscopy （SEM）,transmission electron microscopy （TEM） and scanning transmission electron microscopy （STEM）.The crystals were grown by the floating zone （FZ） method.Both cuboidal and spherical γ＇ precipitates were formed after a two-step aging.The size of the cuboidal γ＇ phases first increased and then decreased with the extension of the second-step aging time.Re,Co and Cr strongly concentrated in the γ phase whereas Ni and Al enriched in the γ＇ phase.Thermodynamic calculation by JMatPro was performed to explain the experimental observations.
基金supported by the National Basic Research Program of China(2013CB733801)the National Key Research and Development Program of China(2017YFA0104301)thankful to the supports from the Fundamental Research Funds for the Central Universities
文摘With the increasingly promising role of nanomaterials in tissue engineering and regenerative medicine, the interaction between stem cells and nanoparticles has become a critical focus. The entry of nanoparticles into cells has become a primary issue for effectively regulating the subsequent safety and performance of nanomaterials in vivo. Although the influence of nanomaterials on endocytosis has been extensively studied, reports on the influence of stem cells are rare.Moreover, the effect of nanomaterials on stem cells is also dependent upon the action mode. Unfortunately, the interaction between stem cells and assembled nanoparticles is often neglected. In this paper, we explore for the first time the uptake of γ-Fe2O3 nanoparticles by adipose-derived stem cells with different passage numbers. The results demonstrate that cellular viability decreases and cell senescence level increases with the extension of the passage number. We found the surface appearance of cellular membranes to become increasingly rough and uneven with increasing passage numbers. The iron content in the dissociative nanoparticles was also significantly reduced with increases in the passage number. However, we observed multiple-passaged stem cells cultured on assembled nanoparticles to have similarly low iron content levels. The mechanism may lie in the magnetic effect of γ-Fe2O3 nanoparticles resulting from the field-directed assembly. The results of this work will facilitate the understanding and translation of nanomaterials in the clinical application of stem cells.
