Catalytic Synthesis and Characterization of Biodegradable ...

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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 ‐ 132 ‐
‐ 133 ‐ Conclusion and Future Prospects forms of solid film, nano/micro fibrous film, mesoporous scaffold or drug-eluting stent coating should be constructed and evaluated in the field including induced cell differentiation and proliferation, cell adhension or retardation, antibacterials and so on. Additionally, the MR and ESR properties of the TMEPO radical also endow the copolymers with promising use as the “soft” bioimaging probes in vivo. As shown in our chapter 6, the core-shell micellar structure was able to protect the TEMPO from being reduced by reductant in a relatively longer time as compared to the free TEMPO molecules and reduced cytotoxicity was also observed. However, the stability of the micelles in the blood stream is still the problem encountered. The further improved stability and MR or EPR signal intensity are now under investigation. One of the strategies is to prepare core cross-linked nanogels, which may significantly improve the stability of the nanoparticles. And the nanogels can also be produced with stimuli responsive monomers, so that the obtained nano-probe could generate different signals in response to diverse environment for applications in probing various inner parts in vivo.
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Catalytic Synthesis and Characteriz
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Preface Biodegradable polyesters ha
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Chapter 3 Polymerization of Lactic
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Chapter 1 Polymerization and Applic
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- 3 - Polymerization and Applicatio
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1.2.2 Aluminum Catalysts - 7 - Poly
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1.3 Polylactide 1.3.1 Introduction
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- 13 - Polymerization and Applicati
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1.3.4 Application of PLA Figure 1.3
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1.5.1.4 Polyaniline (PANi) - 21 - P
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1.6.1 Radical Polymers for Organic
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initialization of the device by app
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1.6.2.4 Others - 49 - Polymerizatio
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182. R. B. Weller, J. Invest. Derma
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Chapter 2 Synthesis and Electrochem
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Synthesis and Electrochemistry of S
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Chapter 3 3.1 Introduction Poly(lac
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Chapter 3 polydispersity index (PDI
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Chapter 3 aluminum based complexes
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Chapter 3 3.5 Conclusions Co(III) c
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Chapter 3 22. Z. H. Tang, X. S. Che
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Page 96 and 97: Chapter 4 the proton of methenyl gr
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Page 104 and 105: Chapter 4 The 1 H NMR and 13 C NMR
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Page 126 and 127: Chapter 6 6.3 Synthesis of MPEG-b-P
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Page 149: Acknowledgments The present thesis
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