Biomedical Engineering Reference
In-Depth Information
C
H
3
HO
CH
2
CH
2
OH
2
CH O
CH
2
CH
2
OH
m
n
n
32
CH
3
CH
3
HO
CH
2
CH
OH
2
CH
2
OH
2
CH
OH
n
m
n
33
CH
3
CH
3
HO H
2
CH
2
OCH
CH
2
CH
2
CH
OCH
2
CH
2
OH
n
n
m
m
NCH
2
CH
2
N
HO H
2
CH
2
OCH
CH
3
CH
2
CH
2
CH
CH
3
OCH
2
CH
2
OH
m
n
n
m
34
CH
3
C
H
3
HO H H
2
OCH
2
CH
2
CH
2
CH
2
OCH
2
CH O
H
n
n
m
m
NCH
2
CH
2
N
HO H H
2
OCH
2
CH
2
m
CH
2
CH
2
OCH
2
CH O
H
n
n
m
CH
3
CH
3
35
(D)
(D) PEO-based hydrogel: 32. Pluronic, 33. Pluronic R, 34. Tetronic, and
35.Tetronic R.
Figure 1.2.
Chemical structures of some commonly used biodegradable
and nondegradable polymers in tissue engineering.
1
etc.
1
,
5
,
7
Generally, 3D porous scaffolds can be fabricated from nat-
ural and synthetic polymers (Fig. 1.2 shows these chemical struc-
tures), ceramics, metal in very few cases, composite biomaterials,
and cytokine release materials. Very recently, “intelligent” scaffolds
arebeingextensivelytestedtomimicthehumanbody'senvironment
as the ECMto Mother Nature.
1.2.2
Bioceramic Scaffolds
“Bioceramic” is a term introduced for biomaterials that are pro-
duced by sintering or melting inorganic raw materials to create
an amorphous or a crystalline solid body that can be used as an
implant. Porous final products have been mainly used as scaffolds.
The components of ceramics are calcium, silica, phosphorous, mag-
nesium, potassium, and sodium. Bioceramic used in the fabrication
for tissue engineering might be classified as nonresorbable (rela-
tivelyinert),bioactive,orsurfaceactive(semi-inert)andbiodegrad-
ableorresorbable(noninert).Alumina,zirconia,siliconenitride,and
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