179
Nanorobotic Manipulation for a Single Biological Cell
10 μm
a
b
10 μm
FIGURE 9.10
Electron microscopic images of yeast cells and culturing plate: (a) under HV mode and (b)
under E-SEM mode.
is surrounding the cells, is gradually evaporated until showing up. From
Figure 9.10b, the remaining water can be seen in the intercellular spaces
of yeast cells as black contrast. Almost all of the yeast cells maintain their
spherical shape in a water-containing condition with E-SEM operation.
To reveal the effect of observation with HV and E-SEM modes, the yeast
cells were cultured again after observation. The plate was divided into three
regions: cultured after water dispersion, SEM observation (HV), and E-SEM
observation. The number of yeast cell colonies in the E-SEM mode were greater
than in HV mode. From this experiment, the living cell rate using E-SEM mode
was almost the same order as that under initial conditions of water dispersion.
9.5 Stiffness Measurements of Single Cells
Using Conventional AFM Cantilevers
9.5.1 Stiffness Measurement of Single Yeast Cells Depends on Cell Sizes
The single-cell stiffness measurement is presented using an E-SEM nanorobotic manipulation system for yeast cells (Ahmad et al. 2008a, 2008b). A schematic of experimental setup is presented in Figure 9.11. The yeast cells were
fixed on the temperature-controlled stage in perpendicular direction with
an AFM cantilever. The position of the AFM cantilever was controlled by the
nanomanipulator to apply the compression force on each cell. The E-SEM
can provide real-time observations, that is, a cell being approached, touched,
indented, and finally penetrated/burst by the AFM cantilever, can be seen
clearly. The penetration of a single cell by the AFM cantilever was also measured from the occurrence of the cell bursting via real-time observation.
An E-SEM photo showing the penetration of single yeast cells is shown
in Figure 9.12. The penetration forces clearly show a strong relationship
between cell size and strength; the latter increases with an increase in cell
Nanorobotic Manipulation for a Single Biological Cell
10 μm
a
b
10 μm
FIGURE 9.10
Electron microscopic images of yeast cells and culturing plate: (a) under HV mode and (b)
under E-SEM mode.
is surrounding the cells, is gradually evaporated until showing up. From
Figure 9.10b, the remaining water can be seen in the intercellular spaces
of yeast cells as black contrast. Almost all of the yeast cells maintain their
spherical shape in a water-containing condition with E-SEM operation.
To reveal the effect of observation with HV and E-SEM modes, the yeast
cells were cultured again after observation. The plate was divided into three
regions: cultured after water dispersion, SEM observation (HV), and E-SEM
observation. The number of yeast cell colonies in the E-SEM mode were greater
than in HV mode. From this experiment, the living cell rate using E-SEM mode
was almost the same order as that under initial conditions of water dispersion.
9.5 Stiffness Measurements of Single Cells
Using Conventional AFM Cantilevers
9.5.1 Stiffness Measurement of Single Yeast Cells Depends on Cell Sizes
The single-cell stiffness measurement is presented using an E-SEM nanorobotic manipulation system for yeast cells (Ahmad et al. 2008a, 2008b). A schematic of experimental setup is presented in Figure 9.11. The yeast cells were
fixed on the temperature-controlled stage in perpendicular direction with
an AFM cantilever. The position of the AFM cantilever was controlled by the
nanomanipulator to apply the compression force on each cell. The E-SEM
can provide real-time observations, that is, a cell being approached, touched,
indented, and finally penetrated/burst by the AFM cantilever, can be seen
clearly. The penetration of a single cell by the AFM cantilever was also measured from the occurrence of the cell bursting via real-time observation.
An E-SEM photo showing the penetration of single yeast cells is shown
in Figure 9.12. The penetration forces clearly show a strong relationship
between cell size and strength; the latter increases with an increase in cell