Svaldo Lanero Tiziana, Cavalleri Ornella, Krol Silke, Rolandi Ranieri, Gliozzi Alessandra
Physics Department, University of Genoa, Via Dodecaneso 33, 16146 Genoa, Italy.
J Biotechnol. 2006 Aug 5;124(4):723-31. doi: 10.1016/j.jbiotec.2006.02.016. Epub 2006 Apr 4.
We have studied the mechanical properties of encapsulated Saccharomyces cerevisiae yeast cells by performing AFM force measurements. Single living cells have been coated through the alternate deposition of oppositely charged polyelectrolyte layers and mechanically trapped into a porous membrane. Coated and uncoated cells in presence/absence of bud scars, i.e. scars resulting from previous budding events, have been investigated. No significant differences between encapsulated and bare cells could be inferred from AFM topographs. On the other hand, investigation on the system elasticity through the acquisition and analysis of force curves allowed us to put in evidence the differences in the mechanical properties between the hybrid cell/polyelectrolyte system and the uncoated cells. Analysis of the curves contact region indicates that the polyelectrolyte coating increases the system rigidity. Quantitative evaluation of the cell rigidity through the Hertz-Sneddon model showed that coated cells are characterized by a Young's modulus higher than the value obtained for uncoated cells and similar to the value observed on the bud scar region of uncoated cells.
我们通过进行原子力显微镜（AFM）力测量研究了包封的酿酒酵母细胞的力学性能。单个活细胞通过交替沉积带相反电荷的聚电解质层进行包被，并机械捕获到多孔膜中。研究了存在/不存在芽痕（即先前出芽事件产生的疤痕）的包被和未包被细胞。从AFM形貌图中无法推断出包封细胞和裸露细胞之间的显著差异。另一方面，通过获取和分析力曲线对系统弹性进行研究，使我们能够证明杂化细胞/聚电解质系统与未包被细胞在力学性能上的差异。曲线接触区域的分析表明，聚电解质包被增加了系统的刚性。通过赫兹-斯内登模型对细胞刚性进行定量评估表明，包被细胞的特征在于其杨氏模量高于未包被细胞的值，且与未包被细胞芽痕区域观察到的值相似。
