Catalytic Synthesis and Characterization of Biodegradable ...

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Chapter 1 1.6.2.3 Electronic Paramagnetic Resonance (EPR) imaging Electron paramagnetic resonance imaging (EPRI) is one of the recent functional imaging modalities that can provide valuable in vivo physiological information, such as tissue redox status, pO2, pH, and microviscosity, based on variation of EPR spectral characteristics, i.e., intensity, linewidth, hyperfine splitting, and spectral shape of free radical probes. 201 EPR imaging (EPRI) can obtain 1D–3D spatial distribution of such spectral components using several combinations of magnetic field gradients. With the addition of appropriate paramagnetic probes, the sensitivity of EPR on a molar basis is about 700 times greater than that of NMR. For EPRI applications, the spins probes should be (1) chemically stable and water soluble in biological media; (2) have simple EPR spectrum at ambient temperature; (3) have pharmacological half-time of at least 10 min to permit the imaging; (4) be non-toxicity. 202 The most used species are nitroxides, such as TEMPO radicals, due to their excellent EPR effect. However, the small molecular species pose some limitations, such as non-selective accumulation in normal tissues, quickly renal clearance, and rapid reduce under the reduction environment in vivo. 203 To solve these issues, Nagasaki and co-workers have designed core–shell-type nanoparticles carrying stable radicals in the core (Figure 1.6.8). 204, 205 The nanoparticles showed intense EPR signals and could resist to reduction environment even at the presence of 3.5 mM ascorbic acid which suggested the promising use of these nanoparticles to be use as the EPR probes in vivo. Further studies of such nanoparticles applied in vivo have revealed that the RNPs had more sufficient long-term blood circulation compared to the TEMPOL free radicals and were of extremely low toxicity due to the confinement of the TEMPO moieties in the nanoparticle core. Especially, the RNPs were pH sensitive, the L-band EPR signal could be observed only at the pH value below 6. Therefore, the pH-sensitive RNPs demonstrated the promising use as the EPR probes for low pH circumstances in vivo. Figure 1.6.8 Illustration of the radical-containing nanoparticle. 204 ‐ 48 ‐
1.6.2.4 Others - 49 - Polymerization and Applications of Biodegradable Polyesters Stimuli-responsive polymers have step critical improvement to be developed as the biomedical materials. There are various factors that have been discovered to induce responsive of the polymers such pH, temperature, light, electric/magnetic field, biological events and so on. 206 Due to one electron redox properties of the nitroxyl radicals, polymers bearing these compounds are expected to have the redox sensitivity that may find potential use as the biomedical materials. Yoshida and Tanaka have proposed the oxidation-induced 207 and reduction-induced 208 micellization of a diblock copolymer containing stable nitroxyl radicals. Light scatting technology and UV-Vis absorbance were used to characterization of the reversible micellization induced by the redox systems which have been illustrated in the Figure 1.6.1. However, the stimuli-responsive systems the authors have studied were performed in organic solvent which is far beyond the applications as biomaterials. Therefore, further efforts should be needed to investigate the reversible self-assembly systems in the aqueous or physiological medium and thus applications in biomedical field could be found. Reference 1. LS. Nair, L. C, Prog. Polym. Sci. 2007, 32, 762. 2. D. J. Brunelle, M. R. Korn, Proceedings of Symposium of the American Chemical Society, March 2003, Washington, DC 2005, 281. 3. J. H. Clements, Ind. Eng. Chem. Res 2003, 42, 663. 4. S. Inoue, H. K., T. Tsuruta, J. Polym. Sci., Part B: Polym. Phys. 1969, 7, 287. 5. S. Inoue, H. K., T. Tsuruta, Makromol. Chem 1969, 130, 210. 6. M. Kobayashi, S. I., T. Tsuruta, Macromolecules 1971, 4, 658. 7. M. Kobayashi, Y. L. T., T. Tsuruta, S. Inoue, Makromol.Chem 1973, 169, 69. 8. M. Kobayashi, S. I., T. Tsuruta, J. Polym. Sci. Polym. Chem. Ed. 1973, 11, 2383. 9. S. Inoue, M. K., H. Koinuma, T. Tsuruta, Makromol.Chem 1972, 155, 61. 10. K. I. Soga, E.; Hattori, I., Polym. J. 1981, 13, 407. 11. A. Rokicki, U.S. Patent 4,943,677, 1990. Products and Chemicals, Inc.; Arco Chemicals Co. 1990. 12. D. J. S. Darensbourg, N. W.; Katsurao, T., J. Mol. Catal. A 1995, 104, L1. 13. D. J. H. Darensbourg, M. W.; Reibenspies, J. H., Polyhedron 1996, 15, 2341.
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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 47 and 48: 1.6.1 Radical Polymers for Organic
Page 51 and 52: initialization of the device by app
Page 53: - 47 - Polymerization and Applicati
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
Page 86 and 87: Chapter 3 polydispersity index (PDI
Page 88 and 89: Chapter 3 aluminum based complexes
Page 90 and 91: Chapter 3 3.5 Conclusions Co(III) c
Page 92 and 93: Chapter 3 22. Z. H. Tang, X. S. Che
Page 94 and 95: Chapter 4 4.1 Introduction Stimulus
Page 96 and 97: Chapter 4 the proton of methenyl gr
Page 98 and 99: Chapter 4 attributed to the amide g
Page 100 and 101: Chapter 4 4.4 Thermal Properties Th
Page 102 and 103: 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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