Biomedical Engineering Reference
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Figure 32.4.
Instrumentation used for the production of alginate
microbeads that employed a high voltage in obtaining even and standard
microbeads. The syringe has the maximum capacity of 5.0 mL, and the
power can supply a voltage up to 20 KV. The position of the calcium (II)
ionsolutionisatafixeddistanceof10cmfromthetipoftheneedle,andthe
injection rate is set at 10 mL hour
-
1
.
illustrated in Fig. 32.4. The applied voltage ranging from 15 to 20
KV generates an electrostatic repulsion force on the inner-side algi-
nate solution that subsequently causes it to expel out of the needle
head.Theoutletoftheneedleheadwasfacedtowardsatargetbottle
containing a solution of calcium (II) ions. This has successfully pro-
duced even-sized alginate beads having a size below 1 mm in a very
fastrateandconveniently.Besides,thePLGAmicrosphereswerealso
homogenously distributed withinthe alginate matrix (Fig. 32.4).
32.3.4
Evaluation of the Oxygen-Releasing Profile
32.3.4.1 Direct observation
The simplest evaluation way on the release of oxygen from ORMs
is via qualitative observation by the naked eye under an optical
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