Catalytic Synthesis and Characterization of Biodegradable ...

More documents

Recommendations

Info

Chapter 1 PBCLA could be achieved. Though the TAM content was improved, the release of TAM from the materials seen to be less effective even in the presence of hydrolysis lipase. Only less than 10 % of the TAM was released after 6 days. In order to solve this issue, a more versatile method has been investigated recently. The TAM nitroxyl radicals were loaded in the biodegradable PEAs nanofiber membranes instead of chemical conjugation. 195 The payload of the TAM in the nanofiber could be tunable by pre-loading different amount of TAM and the release kinetic study revealed that the encapsulated TAM would be completely released from the membranes within 5 days. Figure 1.6.6 The effect of TAM-PGA on the proliferation of human smooth muscle. 196 1.6.2.2 Magnetic Resonance Imaging (MRI) MRI allows noninvasive imaging of deep internal structure of the body and, is widespread use in clinical diagnostic of physiologic and pathologic changes of disease. For MRI, the paramagnetic species are needed to serve as the contrast agents to enhance the image contrast. The most commercially used MR contrast agents are the gadolinium chelates, such as gadolinium diethylenetriaminepentaacetic aicd (Gd-DTPA). However, these agents are non-selective distribution in tissues and have short resistant time in tumors. Nitroxyl radicals are only well-known for their electronic paramagnetic resonance (EPR) properties until 1984, the T1 contrast property was found. Afterward, MRI applications of the nitroxyl radicals have been extensively investigated owing to their chemical flexibility, feasible preparation and low toxicity as comparison with conventional gadolinium chelates. Unfortunately, there are two fetal flaws would emerge when applied the nitroxyl radical MRI reagents in vivo. One is the relatively low MR relaxivities, while the other is the ‐ 46 ‐
- 47 - Polymerization and Applications of Biodegradable Polyesters paramagnetic nitroxyl radical may be reduced to diamagnetic hydroxylamine with the loss of T1 MR relaxation in the internal reduction environment. Figure 1.6.7 illustration of HPS-TEMPO. To address the abovementioned issues, several strategies have been reported, including conjugation of nitroxyl radical compounds with dendritic/hyperbranched polymers or copolymerization with hydrophilic monomers. As an example, Winalski et al. 197 reported to find that the fourth-generation polypropylenimide-(DAB) and third-generation polyamidoamide-(PAMAM) dendrimer-linked nitroxides had greater relaxivity than Gd-DTPA and the selective enhance contrast were observed in healthy articular cartilage. The relaxivities of the compounds were found to increase as the increase of nitroxides that incorporated in the dendrimers. This result was also observed by Ghandehari et al. and Koga et al.. Koga and co-workers have synthesized a series of high water-soluble hyperbranched poly(styrene) (HPS) carrying stable TEMPO radicals (Figure 1.6.7). 198 The relaxivity 14 mM -1 s -1 , which is comparable with commercial Gd-DTPA agent, could be obtained when high density of TEMPO radicals has been conjugated with the polymers. Studies by Ghandehari et al. 199 have been reported that N-(2-hydroxylpropyl)methacryamide (HPMA) copolymer-linked nitroxides were synthesized for potential MRI application. The HPMA monomer was firstly copolymerized with reactive MAGGONp monomer and then chemical link with the nitroxides was performed via reactive MAGGONp residues. The relaxicities of the copolymers bearing nitroxides were found to be linear dependent on the nitroxides content in the copolymers which is consistent with the previous report by Winalski et al.. Another strategy has also proposed by Gussoni and co-workers. 200 They have synthesized pH-sensitive poly(amidoamine)s containing TEMPO radicals in the backbone. Though the relaxicity was measured to be not too high, the polymers were found to be tendency to accumulate in the tumor for a sufficient time.
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 47 and 48: 1.6.1 Radical Polymers for Organic
Page 51: 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
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
Page 104 and 105:
Chapter 4 The 1 H NMR and 13 C NMR
Page 106 and 107:
Chapter 4 Cell viability (%) = (Asa
Page 109 and 110:
Chapter 5 Synthesis of Triblock Cop
Page 111 and 112:
5.2 Synthesis of Triblock Copolymer
Page 113 and 114:
Sample Table 1. Feed and result com
Page 115 and 116:
= 25 μm. B: MTT assay for the cyto
Page 117 and 118:
‐ 109 ‐ Synthesis of Triblock C
Page 119:
‐ 111 ‐ Synthesis of Triblock C
Page 124 and 125:
Chapter 6 6.1 Introduction Since th
Page 126 and 127:
Chapter 6 6.3 Synthesis of MPEG-b-P
Page 128 and 129:
Chapter 6 used to characterize the
Page 130 and 131:
Chapter 6 Figure 6.6 Cyclic voltamm
Page 132 and 133:
Chapter 6 vivo cytotoxicity was als
Page 134 and 135:
Chapter 6 NMR. Characterization of
Page 136 and 137:
Chapter 6 CO2 for 24 h. RSC96 cells
Page 141 and 142:
Chapter 7 Conclusion and Future Pro
Page 143 and 144:
‐ 131 ‐ Conclusion and Future P
Page 145 and 146:
‐ 133 ‐ Conclusion and Future P
Page 147 and 148:
13. Xuan Pang, Xuesi Chen, Xiuli Zh
Page 149:
Acknowledgments The present thesis
show all

Catalytic Synthesis and Characterization of Biodegradable ...

Create successful ePaper yourself

Delete template?

Save as template?