Page 69 - Vibrational Spectroscopic Imaging for Biomedical Applications

Algal Cells, Cartilage, and IRENI 45

measurements points at 15, 50, 80, 110, …, 260 minutes have been
recorded.
Data acquisition and analysis were conducted using the Imaging-
Win v. 2.30 software (Walz, Effeltrich Germany).
Figure 2.13 presents the results of the viability study with the
PAM microscope. A total of 35 “healthy looking” Micrasterias sp.

0.8

0.6

F v /F m 0.4

0.2

0.0
50 100 150 200 250
Time (min)
(a)
100
Remaining healthy cells
Histogram of dying cells
80
Cell Fraction (%) 60

40

20
0
50 100 150 200 250
Time (min)
(b)

FIGURE 2.13 Viability study of single Micrasterias cells inside the fl ow
chamber using a PAM microscope. The F /F value of 33 algal cells have
v m
been measured at nine different time points spaced 30 minutes apart
(time = 0 corresponds to the fl ow chamber assembly, fi rst measurement at
15 minute). Panel (a) shows fi ve representative single cell PAM
measurements (dashed, colored lines); the thick, solid black line is the
average over 33 cells. The blue line in panel (b) illustrates the development
over time of the number of viable cells (cells whose F /F stays within one
v m
standard deviation relative to their initial F /F ). It demonstrates that
v m
61 percent algal cells, after an initial decline, stay viable inside the fl ow
chamber for at least 260 minutes. The red bars in panel (b) represent the
histogram of nonviable cells. (Printed with permission from Ref. 18.)