We present methods to characterize mesenchymal stromal cells (MSC) over long time periods in vitro. The methods entail passaging cells multiple times and performing differentiation studies with the cells at each passa...We present methods to characterize mesenchymal stromal cells (MSC) over long time periods in vitro. The methods entail passaging cells multiple times and performing differentiation studies with the cells at each passage. Using an array of surface markers and flow cytometric quantification, the data can be correlated to traditional measures of differentiation such as PCR and staining. Using these methods to quantify the amount of differentiation, we concluded that many common MSC markers do not specifically define MSCs with true stem cell properties. Additionally, adipose-derived as opposed to bone marrow-derived MSCs show long-term CD34+ labeling. The methods described can be used to help identify stem cell markers and to characterize the state of stem cells in vitro. Compiling these data from multiple laboratories would be helpful to determine source, extraction and culture methods needed to obtain high yields of useful stem cells.展开更多
Silk materials with different nanostructures have been developed without the understanding of the inherent transformation mechanism. Here we attempt to reveal the conversion road of the various nanostructures and dete...Silk materials with different nanostructures have been developed without the understanding of the inherent transformation mechanism. Here we attempt to reveal the conversion road of the various nanostructures and determine the critical regulating factors. The regulating conversion processes influenced by a hierarchical charge distribution were investigated, showing different transformations between molecules, nanoparticles and nanofibers. Various repulsion and compressive forces existed among silk fibroin molecules and aggregates due to the exterior and interior distribution of charge, which further controlled their aggregating and deaggregating behaviors and finally formed nanofibers with different sizes. Synergistic action derived from molecular mobility and concentrations could also tune the assembly process and final nanostructures, it is suggested that the complicated silk fibroin assembly processes comply a same rule based on charge distribution, offering a promising way to develop silk-based materials with designed nanostructures.展开更多
文摘We present methods to characterize mesenchymal stromal cells (MSC) over long time periods in vitro. The methods entail passaging cells multiple times and performing differentiation studies with the cells at each passage. Using an array of surface markers and flow cytometric quantification, the data can be correlated to traditional measures of differentiation such as PCR and staining. Using these methods to quantify the amount of differentiation, we concluded that many common MSC markers do not specifically define MSCs with true stem cell properties. Additionally, adipose-derived as opposed to bone marrow-derived MSCs show long-term CD34+ labeling. The methods described can be used to help identify stem cell markers and to characterize the state of stem cells in vitro. Compiling these data from multiple laboratories would be helpful to determine source, extraction and culture methods needed to obtain high yields of useful stem cells.
基金Acknowledgements We thank the National Basic Research Program of China （973 Program, Grant No. 2013CB934400）, the National Natural Science Foundation of China （Grant Nos. 21174097, 81272106 and 81271412）, and the NIH （R01 DE017207）. We also thank the PriorityAcademic Program Development of Jiangsu Higher Education Institutions （PAPD）, the Excellent Youth Foundation of Jiangsu Province （BK2012009）, International S＆T Cooperation Project of the Ministry of S＆T of China （2010DFR30850）, the Key Natural Science Foundation of the Jiangsu Higher Education Institutions of China （11KGA430002） and Jiangsu Provincial Special Program of Medical Science （BL2012004） for support of this work.
文摘Silk materials with different nanostructures have been developed without the understanding of the inherent transformation mechanism. Here we attempt to reveal the conversion road of the various nanostructures and determine the critical regulating factors. The regulating conversion processes influenced by a hierarchical charge distribution were investigated, showing different transformations between molecules, nanoparticles and nanofibers. Various repulsion and compressive forces existed among silk fibroin molecules and aggregates due to the exterior and interior distribution of charge, which further controlled their aggregating and deaggregating behaviors and finally formed nanofibers with different sizes. Synergistic action derived from molecular mobility and concentrations could also tune the assembly process and final nanostructures, it is suggested that the complicated silk fibroin assembly processes comply a same rule based on charge distribution, offering a promising way to develop silk-based materials with designed nanostructures.
