The 鈥淣eedle in the Haystack鈥?Makes the Difference: Linear and Hyperbranched Polyglycerols with a Single Catechol Moiety for Metal Oxide Nanoparticle Coating

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• 作者：Anja Thomas ; Heiko Bauer ; Anna-Maria Schilmann ; Karl Fischer ; Wolfgang Tremel ; Holger Frey
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：July 22, 2014
• 年：2014
• 卷：47
• 期：14
• 页码：4557-4566
• 全文大小：447K
• ISSN：1520-5835

文摘

Multifunctional linear (CA-linPG) and hyperbranched polyglycerols (CA-hbPG) bearing a single catechol unit were synthesized by use of an acetonide-protected catechol initiator for the anionic polymerization of ethoxyethyl glycidyl ether (EEGE) and glycidol, respectively. A key feature for the synthesis of the hyperbranched structures was a selective, partial acetal deprotection step. The single catechol unit among a large number of aliphatic 1,2- and 1,3-diol moieties (i.e., the 鈥渘eedle in the haystack鈥? in both linear and hyperbranched polyglycerols permits dispersion of transition metal oxide nanoparticles in brine, as demonstrated for manganese oxide (MnO) nanoparticles. Molecular weights of the single catechol bearing PGs ranged from 950 to 2350 g路mol^鈥? for CA-linPG and from 3750 to 5750 g路mol^鈥? for CA-hbPG with narrow and monomodal molecular weight distributions (M_w/M_n < 1.23 for linPG and M_w/M_n = 1.22鈥?.48 for hbPG). Both C-linPGs and C-hbPGs are suitable hydrophilic capping agents to generate highly hydroxyl-functional nanoparticles with hydrophilic PG shell. The PG content of the polymer-coated MnO nanoparticles (diameter 17 nm) was in the range 21鈥?4 wt %, as determined via TGA. The MnO nanoparticles with a hydrophilic, multifunctional polyglycerol shell may represent a promising alternative to iron oxide or gadolinium contrast agents for MRI.