Biomedical Engineering Reference
In-Depth Information
so that the concentration of residual EOG is reduced to acceptable
levels.
Radiation sterilization using isotopic 60 Co can also deteriorate
polymerssinceathighdosagethepolymerchainscanbedissociated
or cross-linked according to the characteristics of the chemical
structures. At a 2.5 Mrad dose, the tensile strength and molecular
weight of PLGA decreased. Also, there is a rapid decrease in the
molecular weight of PGA nonwoven felt with increasing doses of
radiation. Thus, it is very important to bear in mind that the prop-
erties and useful lifetime of the PLGA implanted can be significantly
affected by irradiation. The physical properties continued to deteri-
orate with timefollowing irradiation.
Sterilizationmethodsmightsignificantlyaffectthephysicochem-
ical properties of the scaffold matrix. The specific effects with var-
ious methods are determined by the kinds of scaffolds materials
themselves, the scaffold preparation methods, and the sterilization
factors. It is essential that a new standardization for sterilizing scaf-
fold devices bedesigned and established.
1.4 Conclusions
Very recently, regenerative medicine and tissue engineering show
tremendous potential as revolutionary research pushes. Also, many
successful results have been reported in the potential for regen-
erating tissues and organs such as skin, bone, cartilage, nerve
of peripheral and central nerves, tendon, muscle, cornea, blad-
der and urethra, and liver, as well as composite systems like a
human phalanx and joint on the basis of “intelligent” scaffold bio-
materials from polymers, ceramic, metal, composites, and their
hybrids. 41
As previously emphasized, scaffold materials must contain the
site of cellular and molecular induction and adhesion and must
allow for the migration and proliferation of cells through porosity.
They should also maintain strength, flexibility, biostability, and bio-
compatibility to mimic a more natural, 3D environment. With the
advancesofmoresophisticatedCAD/CAMtechniques,wecanmimic
the nature of the human body's structure. Also, the combination of
 
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