Catalytic Synthesis and Characterization of Biodegradable ...

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Chapter 1 experiments with and without applying electrical potentials, the dopped electroactive copolymers had the ability of improving the differentiation of PC-12 cells, as shown in Figure 1.5.11. They also prepared a new kind of water-soluble electroactive polymer, aniline pentamer cross-linked chitosan. These new polymers showed good electroactivity even in aqueous solution. The MTT assay, cell adhesion test, and degradation assessment in the presence of enzyme confirmed that these polymers had good biocompatibility and biodegradability. The electroactive polymers can obviously improve the neuronal differentiation of PC-12 cells even without the extra electrical stimulation, as shown in Figure1.5.12. Figure 1.5.12 Visualization of PC-12 neurite outgrowth by micrographs for the substrates (A) without electroactivity (chitosan), (B) with electroactivity (aniline pentamer cross-linked chitosan) on day 5. 139 A B As the study progressing, Chen et al. found that the oligomers without high conductivity and the polymers containing oligomers also showed improvement in the C6 cell differentiation in the absence of electrical stimulation, as shown in Figure 1.5.13. In the culture medium, the only difference from the electroactive polymers may be the exchange of the ion between the medium with polymer, and between the polymer with cells, which means the electroactivity changed the ion exchange between the cells and medium. ‐ 30 ‐
- 31 - Polymerization and Applications of Biodegradable Polyesters Figure 1.5.13 Visualization of C-6 outgrowth by micrographs in the culture medium (a), (b) in the presence of aniline pentamer cross-linked chitosan, (c) and (d) without aniline pentamer cross-linking chitosan. Besides the extensively investigated PPy and PANi, several electroactive polymers have been also studied, such as polythiophene (PT) and others. For example, a series of polymers composed of a PT backbone with oligosiloxane grafted to the b position of the thiophene rings was prepared. 140 All the polymers exhibited different conductivities after doped with iodine. However, the iodine is toxic to cells and the authors only investigated the biocompatibility of undoped polymers. The carbon-carbon bond of PT made it inherently nonbiodegradable. To overcome this drawback, some reports concentrated on the synthesis of biodegradable elcetroactive polymers containing heterocycles unit. For example, ester linkers were introduced to connect the conductive heterocycles (Figure. 1.5.14A). 96 The resulted polymer is conductive, and more importantly, it is biodegradable in the presence of esterases which made it be applicable in vivo. The conductivity of the polymer is mainly attributed to inter and intra “electron hopping” formed by the overlap of conjugated regions. However, the doping agent is also iodine. Despite this drawback, the undoped polymer was biocompatible in vitro. Nerve cells adhered to polymer film and readily expressed their nerve-like phenotype by extending neurites after one day (Figure 1.5.14B, left). After 8 days, significant cell proliferation was observed (Figure 1.5.14B, right). These data demonstrate that in addition to being non-toxic to cells in culture, this biodegradable electroactive polymer can also support cell attachment and proliferation. Subsequently, in vivo biocompatibility of this polymer was
Page 1 and 2: Catalytic Synthesis and Characteriz
Page 3 and 4: Preface Biodegradable polyesters ha
Page 5 and 6: Chapter 3 Polymerization of Lactic
Page 7 and 8: Chapter 1 Polymerization and Applic
Page 9 and 10: - 3 - Polymerization and Applicatio
Page 13 and 14: 1.2.2 Aluminum Catalysts - 7 - Poly
Page 17 and 18: 1.3 Polylactide 1.3.1 Introduction
Page 19 and 20: - 13 - Polymerization and Applicati
Page 21 and 22: 1.3.4 Application of PLA Figure 1.3
Page 27 and 28: 1.5.1.4 Polyaniline (PANi) - 21 - P
Page 35: - 29 - Polymerization and Applicati
Page 47 and 48: 1.6.1 Radical Polymers for Organic
Page 51 and 52: initialization of the device by app
Page 55 and 56: 1.6.2.4 Others - 49 - Polymerizatio
Page 63 and 64: 182. R. B. Weller, J. Invest. Derma
Page 65 and 66: Chapter 2 Synthesis and Electrochem
Page 67 and 68: Synthesis and Electrochemistry of S
Page 79: Synthesis and Electrochemistry of S
Page 84 and 85: 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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Chapter 4 4.1 Introduction Stimulus
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Chapter 4 the proton of methenyl gr
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Chapter 4 attributed to the amide g
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Chapter 4 4.4 Thermal Properties Th
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Chapter 4 Figure 4.8 MTT assay for
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Chapter 4 The 1 H NMR and 13 C NMR
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Chapter 4 Cell viability (%) = (Asa
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Chapter 5 Synthesis of Triblock Cop
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5.2 Synthesis of Triblock Copolymer
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Sample Table 1. Feed and result com
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= 25 μm. B: MTT assay for the cyto
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‐ 109 ‐ Synthesis of Triblock C
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‐ 111 ‐ Synthesis of Triblock C
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Chapter 6 6.1 Introduction Since th
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Chapter 6 6.3 Synthesis of MPEG-b-P
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Chapter 6 used to characterize the
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Chapter 6 Figure 6.6 Cyclic voltamm
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Chapter 6 vivo cytotoxicity was als
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Chapter 6 NMR. Characterization of
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Chapter 6 CO2 for 24 h. RSC96 cells
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Chapter 7 Conclusion and Future Pro
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‐ 131 ‐ Conclusion and Future P
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‐ 133 ‐ Conclusion and Future P
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13. Xuan Pang, Xuesi Chen, Xiuli Zh
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Acknowledgments The present thesis
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