Biomedical Engineering Reference
In-Depth Information
(a)
(b)
FIGURE 11.53 SEM images of insulin particles aerosolized by electrospraying. Average particle diam-
eter—98
19 nm. (Reprinted from Gomez, A. et al., J. Aerosol Sci. , 29, 561, 1998. © Elsevier Science. With
permission.)
±
divide normally after electrospraying. No adverse effects on living cells have been observed when
they were processed with this technique. Jurkat cells were grown for 48 h in RPMI 1640 growth
medium with 10% fetal calf serum in an incubator at 37°C and 4% CO 2 . Cell viability was assessed
by staining with Trypan blue, and viable cells were counted by using a bright-fi eld hemocytometer
with a phase microscope. A cell suspension in 2-5 mL containing 1-2
10 6 cells/mL was used
for each electrospraying experiment. In the process, Jurkat cell suspension was syringed through a
needle, which initiated the aerosolization of the suspension. The fl ow rate and the applied voltage
were varied over a rather large parametric range to establish a stable spraying mode, but electro-
spraying of the Jurkat cell suspension occurred in an unstable mode, resulting in a polydispersed
distribution of droplets. This feature was attributed to the high electrical conductivity and the high
surface tension of the solution. Figure 11.54 shows the unstable spraying mode. In the investigation,
electrospraying of Jurkat cell suspension was carried out at an applied voltage of 8.5 kV and a fl ow
rate of 10 −8 m 3 /s. Figure 11.55 shows the observed results of the electrosprayed cells. The living
cells were observed by optical microscopy for about 2 h after the electrospraying. No signs of
cellular damage were seen as the result of this processing route. Cells changed their morphology
over time (cells X and Y), and in some cases the cells underwent cytokinesis (cell Q) as shown
in Figures 11.55b through 11.55f. This experiment has elucidated the ability to successfully
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