Catalytic Synthesis and Characterization of Biodegradable ...

Chapter 5
blocks, which exhibiting no Tm or Tg in the test temperature range. Figure 4B showed the
decomposition behaviors of PLA, TLT1, TLT2 and PTAm. PLA began to decompose at 200
o C, which originating from the chain end, and lost all the weight at 300 o C. The
decomposition temperature of PTAm occured at 50 o C and lasted to 500 o C. For TLT1 and
TLT2, their thermo-decomposition behaviors were more similar to PTAm because the end
hydroxyl groups of PLA were protected by the PTAm chains.
Figure 4. (A) DSC traces of the PLA, PTAm, and TLT in second heating. (B) TGA curves of
PLA, PTAm, and TLT.
5.4 Cytotoxicity and Biocompatibility of Copolymers
In the biomedical application, TLT copolymer should be non-toxic and able to support cell
adhesion and growth. Like described in Chapter 4, the cytotoxicity and cell compatibility of
the block copolymers were assessed in vitro. To better observe the shape of the adherent cells
(particularly whether irregular polygonal or original elliptical), the samples were prepared by
regular cell-staining method, i.e. staining separately with nucleus and F-actin.
Figure 5. A: Phase contrast microscopy images of RSC96 cells after incubation on different
polymer films for 48h. (1) PLA film, (2) PTAm film, (3) TLT1 film and (4) TLT2 film. Scale bar
‐ 106 ‐