Temperature Sensitization of Liposomes by Use of Thermosensitive Block Copolymers Synthesized by Living Cationic Polymerization: Effect of Copolymer Chain Length
| Autor: | Tomohide Yoshida, Shokyoku Kanaoka, Sadahito Aoshima, Taishi Murakami, Toru Takagishi, Kenji Kono, Yasuhiro Haba |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Vinyl Compounds
Polymers Biomedical Engineering Pharmaceutical Science Bioengineering Living cationic polymerization Phase Transition Structure-Activity Relationship chemistry.chemical_compound Differential scanning calorimetry Phosphatidylcholine Polymer chemistry medicine Copolymer Moiety Pharmacology Liposome Phosphatidylethanolamines Organic Chemistry Temperature technology industry and agriculture Vinyl ether Fluoresceins Calcein chemistry Liposomes Phosphatidylcholines Ethers Biotechnology medicine.drug |
| Zdroj: | Bioconjugate Chemistry. 16:1367-1374 |
| ISSN: | 1520-4812 1043-1802 |
| Popis: | We prepared block copolymers of (2-ethoxy)ethoxyethyl vinyl ether (EOEOVE) and octadecyl vinyl ether (ODVE) with the number average molecular weights of 6900, 9300, and 16 700 by living cationic polymerization. The poly(EOEOVE) block acts as a temperature-sensitive moiety, and the poly(ODVE) block acts as an anchor moiety. We also investigated the effect of chain length of the copolymer poly(EOEOVE) block on the ability to sensitize liposomes. The copolymers underwent a coil-globule transition at approximately 36 degrees C in the presence of a membrane of egg yolk phosphatidylcholine (EYPC), detected using differential scanning calorimetry (DSC). Liposomes encapsulating calcein, a water-soluble fluorescent dye, were prepared from mixtures of dioleoylphosphatidylethanolamine, EYPC, and the copolymers. While the copolymer-modified liposomes released little calcein below 30 degrees C, release was enhanced above 35 degrees C, indicating that dehydrated copolymer chains destabilized the liposome membrane. In addition, copolymers with a longer poly(EOEOVE) block induced a more drastic enhancement of contents release in a narrow temperature region near the transition temperature of the poly(EOEOVE) block. As a result, the copolymer with an average molecular weight of 16 700 generated highly sensitive liposomes that produced rapid and dramatic release of the contents in response to temperature. |
| Databáze: | OpenAIRE |
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