794
6
The swelling study of calcium alginate beads containing AgNPs and blank beads was carried
out in PBS, pH 7.4 (Figure 3). A time-dependent increase on the swelling ratio was observed for both
beads until the maximum swelling ratio was found after 180 and 240 min, for the beads containing
AgNPs and the blank beads respectively. This was followed by a continual drop of such ratio for both
beads. Moreover, there was evidence showed that the swelling ratio of the beads containing AgNPs
was significantly higher than the blank beads between 90 to 180 min of incubation (
Q
<0.05).
Figure
3 Swelling study of the beads at different incubation time
The swelling study of blank beads (
z
) and calcium alginate beads containing AgNPs (
) was carried out in PBS, pH 7.4
from 0 to 360 min. This swelling ratio was presented as mean ± S.D. Asterisks (*) show a significant difference between
both beads at
Q
<0.05 using an independent-samples T test.
This study showed that the swelling ratio of both beads was time-dependent. This was similar
to previous study [10]. The maximum swelling ratio was found after 180 and 240 min for the beads
containing AgNPs and the blank beads, respectively, and this was followed by a drop of the swelling
ratio of both beads. These drops might be because of the disassociation between the alginate and
calcium ions, which then resulted in the reduction in the swelling ratio. Moreover, the maximum
swelling ratio of the beads containing AgNPs was faster than that observed of the blank beads, and
there was evidence showed that the swelling ratio of the beads containing AgNPs was higher than that
observed of the blank beads. This might be because of the charged AgNPs, impregnated within the
beads, which might lead to more water molecules penetrating into the beads as a result of an osmotic
pressure [10]. This might then result in the faster maximum swelling ratio as well as the higher swelling
ratio of the beads containing AgNPs, when compared with the blank beads.
Conclusion
In this study, calcium alginate beads containing AgNPs were prepared by a two-step method,
in which the AgNP suspension was initially synthesised and subsequently followed by the bead
formation. The size of the beads containing AgNPs and the blank beads was measured using the
optical microscope. The water loss (%) of both beads was higher than 97%, and there was no
significant difference in the water loss (%) between both beads. Moreover, the time-dependent
0 60 120 180 240 300 360 420
0
10
20
30
40
50
Time (min)
Swelling ratio
