碩士 / 國立臺灣科技大學 / 化學工程系 / 105 / Cyanophycin granule polypeptide is a non-ribosomal polypeptide, consisting of aspartic acid as a backbone with arginine and lysine as the side chains. When cyanophycins are produced from genetic recombinant strains, lysine can replace some of the arginine on the side chain. The primary amine on lysine provides a moderate condition for chemical modification. Cyanophycin has been shown to be a thermo-responsive polymer, which has an upper critical solution temperature in the aqueous solution. However, the water insoluble cyanophycin can hardly be dissolved in neutral aqueous solution, which might limit its applications.
In this study, we used polyethylene glycol methyl ether (mPEG) to modify insoluble cyanophycin. After reaction, the functional groups of the (insoluble cyanophycin) - (mPEG) conjugates were analyzed by Fourier transform infrared spectroscopy. The grafting degrees of the conjugates were determined by the TNBSA colorimetrically.
Grafting mPEG was found to enhance the solubility of insoluble cyanophycin. The phase transition temperatures of the conjugates were around 40℃. The effects of grafting degrees, conjugate concentrations, pH, and molecular weights of mPEG on the phase transition temperature were examined. The particle sizes of conjugates were measured by transmission electron microscopy and dynamic light scattering.
Finally, we used (insoluble cyanophycin) - (mPEG) conjugates to encapsulate doxorubicin, and investigated the encapsulation efficiency by changing the ratios of drug to polymer as well as the methods of encapsulation. The results showed that using an instant cooling method at a drug/polymer ratio of 1/3, the encapsulation efficiency could be 40%. Because the (insoluble cyanophycin) - (mPEG) conjugates were thermoresponsive, we also tried to raise the temperature during the release. The results showed that the release increased from 25 % to a final 95 %, indicating that temperature can control drug release, and showing the potential to be used in drug delivery.
| Identifer | oai:union.ndltd.org:TW/105NTUS5342068 |
| Date | January 2017 |
| Creators | Yi-Hao Huang, 黃奕豪 |
| Contributors | Wen-Chi Tseng, 曾文祺 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 115 |
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