Langmuir 2012-03-06

Protection/Deprotection of surface activity and its applications in the controlled release of liposomal contents.

Xueshu Li, Yan Zhao

Index: Langmuir 28(9) , 4152-9, (2012)

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Abstract

The micelles of two tripropargylammonium-functionalized cationic surfactants were cross-linked by a disulfide-containing diazido cross-linker in the presence of Cu(I) catalysts. With multiple residual alkyne groups on the surface, the resulting surface cross-linked micelles (SCMs) were postfunctionalized by reaction with 2-azidoethanol and an azido-terminated poly(ethylene glycol), respectively, via the alkyne-azide click reaction. The water-soluble nanoparticles obtained had low surface activity due to the buried hydrophobic tails. Cleavage of the disulfide cross-links by dithiothreitol (DTT) exposed the hydrophobic tails and resumed surface activity of the "caged" surfactants within 2 min after DTT addition. The controlled breakage of the SCMs was used to lower the surface tension of aqueous solutions and trigger the release of liposomal contents on demand.