Biomedical Engineering Reference
In-Depth Information
Fig. 15
Above
: Photo of a two-chamber chip fabricated on glass substrates for preparing
miniaturized cell-encapsulating hydrogel.
Below
: Setup and operation of the two-chamber chip.
(
a
) The system setup. (
b
) PVA solution is introduced into chamber
I
through inlets
1
and
3
.(
c
) The
PMBV/cell suspension is introduced through the same inlet/outlet. Immediately, cell-
encapsulating PMBV/PVA hydrogel spontaneously forms in chamber
I
. After that, cells are
encapsulated in chamber
II
through the same operation. (
d
) With all inlets/outlets open, the chip
is incubated at 37
C in a cell culture incubator. (
e
) After encapsulation for several days, LIVE/
DEAD agents are introduced through inlet
2
and outlet
3
to chamber
I
and through inlet
7
and
outlet
6
to chamber
II
, respectively
prepared in both the microplate (bulk hydrogel) and the chip (miniaturized
hydrogel).
Figure
16
demonstrates representative fluorescence images of LIVE/DEAD
assays of L929 cells after being encapsulated for 4 days in the bulk hydrogel
and in the miniaturized hydrogel. In both hydrogel formats, only few dead cells
(indicated as red fluorescence) were found, indicating that most cells were live after
4 days of encapsulation in both hydrogel formats. Accordingly, almost equal cell
viabilities were calculated (at 4 days), i.e., about 88.7% in the miniaturized hydro-
gel and about 87.8% in the bulk hydrogel (Fig.
17
). This indicates that, after 4 days
of encapsulation, the viability of cells in the miniaturized hydrogel was highly
uniform with that of cells in the bulk hydrogel. After 8 days of encapsulation, the
viability of L929 cells in the miniaturized hydrogel was as high as its viability after
4 days, whereas the viability of L929 cells in the bulk hydrogel decreased slightly to
