Catalytic Synthesis and Characterization of Biodegradable ...

Chapter 7
7.2. Future Prospects
Recent advances of the biomedical use of polyesters have been paid increasing attention
on dealing with the interaction and communication between the materials and life systems,
for which the materials are termed as bioactive materials. In order to obtain bioactive
materials, some modifications towards polyesters are usually taken to achieve bioactive
functionalities, including hydrophobicity-hydrophilicity, softness-hardness, charge-charge
density, stimuli responsiveness, and biological functionality. In the past few years, some
efforts have been made by our lab on the functionalization of PLA and their use in the
biomedical fields. For example, copolymerization of lactide monomer with functionalized
cyclic monomers leads to biodegradable polymers with reactive amino or carboxyl groups
which are subsequently used for conjugation with bioactive molecules such as folate, RGD,
sugars, antibody and drugs. Then, the use of these bio-functionalized materials in, such as
tissue engineering scaffolds or smart drug delivery systems have also been investigated.
Though great efforts have been made, there are still challenges in synthesis of biodegradable
polyesters with precise and smart properties, such as improved cell adhesions and
proliferation, precise targeting drug delivery and triggered release, promoted cell
internalization and so on. Fortunately, by virtue of the recent development on the click
chemistry and living radical polymerization technique (ATRP, RAFT et al.), it is possible for
us to prepare polyesters with diverse structures and architectures, ie. different kinds of
polymers (natural polymers, synthetic polyesters and free radical polymers) can be
conjugated together and great amount of vinyl monomers can be used to bring additional
properties to the polyesters. Thus, it is possible for us to prepare biomedical polymers with
more profound and precise functions for specific biomedical use.
A tentative effort has been made in this thesis on the synthesis of the biodegradable
copolymers of PLA and TEMPO-contained PTAm through combination of ring-opening
polymerization and RAFT living radical polymerization. The biocompatibility and potential
biomedical use were also evaluated. However, it is reasonably attractive to make step further
in the application of the TEMPO-based radical polymers in biomedical fields based on the
unique electronic, magnetic and biological properties of the nitroxyl radicals. Tasks are still
remained in the further investigation of these materials interaction and communication with
cells through electronic transport or nitroxyl radical triggered signal pathway. Materials in the
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