NOVEL MICROSPHERES FOR PROLONGED CELL SURVIVAL - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 635

between organic-synthetic matrices. 2 The functionalized materi-
als act as a smart terminal within the scaffold, having the abil-
ity to interact dynamically with the cell-growing environment and
subsequently control the condition at its optimum. In this aspect,
microspheres encapsulated with either chemical compounds or
bioactive reagents or both can be a good candidate to serve the pur-
pose. Along with the small-size factor that makes integration work
simple, there are several strong driving reasons for the selection of
using microspheres. First, microspheres allow the encapsulation of
various ingredients, and their release from the microcapsule can be
carefullycontrolled.Suchworkshavebeenwelldemonstrated,espe-
cially in the area of drug delivery for encapsulating different kinds
of drugs, and the microspheres manage to target specific treatment
sites with controlled release of dosage. 3 - 5 Second, microsphere sys-
tems increase the life span of an active constituent due to the direct
protection from the shell of the microspheres. This ensures pro-
longed effect or continuous activity of the ingredient without being
deactivated by potential inhibitors from the surrounding or dur-
ing the delivery route to the targeted area. 6 , 7 Third is the flexibil-
ity in the choice of materials and techniques that can be used to
prepare the microspheres. Varieties of matrices either synthetic or
natural are employed for this purpose, eliminating the effect of
incompatibility between the microspheres and the active ingredi-
ents or with the main matrix of the scaffold during its integra-
tion for tissue engineering. 8 The choices of methods to prepare
microspheres are also diverse, and one of the commonly reported
isthedoubleemulsionsolventevaporationtechnique,whichistech-
nically simple, has no instrumentation involved, and is economical
in cost. 9 - 11 Finally, microspheres have been technically and practi-
cally proven to be compatible either in vivo or in vitro in biological
systems. 12 - 14 This avoids the interfering effect that may cause seri-
ous malfunction to cell activities when blended into the scaffold or
used individually for tissue engineering purposes. The advantages
and flexibilities simplify the work of producing novel microspheres
astheeffortcanfocusdirectlyonthesmartproperty,manufacturing
methodology, andits integration for applications.
In dealing with more complex systems such as a large-volume
implant, the issue of stable cell survival and function often became