BIOMATERIALS AND MANUFACTURING METHODS FOR SCAFFOLD IN REGENERATIVE MEDICINE - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 13

consolidation, hydrolysis-assisted solidification, and freezing meth-
ods (see sections 1.4 and 1.6). Therefore, it is very important to
choose the appropriate preparation methods for the physical prop-
erties of desired organs.
1.2.3 Synthetic Polymers
One of the most significant shortages of natural polymers, as will
be discussed in section 1.2.4, is typically expensive, suffering from
batch-to-batch variation, and the possibility of cross-contamination
from unknown viruses or unwanted diseases due to the isolation
from plant, animal, and human tissue. On the contrary, synthetic
polymeric biomaterials might have easily controlled physicochem-
ical properties and quality and no immunogenecity. Also, they can
be processed with various techniques and supplied consistently in
large quantities.
In order to adjust the physical and mechanical properties of
tissue-engineered scaffolds at the desired place in the human
body, the molecular structure, molecular weight, etc., are eas-
ily adjusted during the synthetic process. There are largely
divided two categories: (i) biodegradable and (ii) nonbiodegrad-
able. Some nondegradable polymers are polyvinylalcohol (PVA),
poly(hydroxylethylmethacryalte), and poly(N-isopropylacryamide).
Some synthetic degradable polymers are the family of poly( α -
hydroxy ester)s such as polyglycolide (PGA), polylactide (PLA) and
its copolymer poly(lactide- co -glycolide) (PLGA), polyphosphazene,
polyanhydride, poly(propylene fumarate), polycyanoacrylate, poly-
caprolactone, polydioxanone, biodegradable polyurethanes, etc. 1 , 5 , 7
(Chemical structures are shown in Fig. 1.2A,B,D.)
Among these two polymers, the synthetic biodegradable poly-
mers were preferred for the application of regenerative medicine
and tissue-engineered scaffolds to minimize the chronic foreign-
body reaction and lead to the formation of the completely nat-
ural tissue. That is to say, they can form a temporary scaffold for
mechanical and biochemical support. This section mainly focuses
on the biodegradable polymers and then more detailed fabrication
methods for polymers willbediscussed in sections 1.4 and1.6.