Nanoscience and Nanotechnology CONFOCAL MICROSCOPY AND ATOMIC FORCE MICROSCOPY OF SACCHAROMYCES CEREVISIAE (original) (raw)
We examined the physical properties of the surrounding yeast cell walls by using atomic force microscopy (AFM). The yeast cells were prepared on a cleaned glass substrate for CM observation and were mechanically trapped into a porous membrane for AFM measurement. The confocal image of the yeast cells was measured in air meanwhile the AFM topography images of the cells were measured in both de-ionized (DI) water (pH = 6.9) and phosphate-buffered saline (PBS) solution (pH = 7.4). No significant differences between the AFM topography images of the yeast cells measured in DI water and in phosphate buffered saline (PBS) solution could be inferred. In order to get the quantitative information on the sample elasticity, the force curves between an AFM tip and the yeast cell have been measured. These curves were measured in both DI water and in PBS solution on the same yeast cell using the same AFM cantilever to get the reliable result. The contact region of these force curves in approach mode was then converted into force versus indentation curves. These curves would be fitted with Hertz-Sneddon model for the calculation of the elasticity. Analysis of the curves indicates that there is a difference of the Young's modulus values of the yeast cell in various environments. These data show that the salt buffer solution increases the rigidity of the biological system.
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