Surfactant micelles are dynamic entities with a rapid exchange of monomers. By “clicking” tripropargylammonium-containing surfactants with diazide cross-linkers, we obtained surface-cross-linked micelles (SCMs) that could be multifunctionalized for different applications. They triggered membrane fusion through tunable electrostatic interactions with lipid bilayers. Antenna chromophores could be installed on them to create artificial light-harvesting complexes with efficient energy migration among tens to hundreds of chromophores. When cleavable cross-linkers were used, the SCMs could break apart in response to redox or pH signals, ejecting entrapped contents quickly as a result of built-in electrostatic stress. They served as caged surfactants whose surface activity was turned on by environmental stimuli. They crossed cell membranes readily. Encapsulated fluorophores showed enhanced photophysical properties including improved quantum yields and greatly expanded Stokes shifts. Catalytic groups could be installed on the surface or in the interior, covalently attached or physically entrapped. As enzyme mimics, the SCMs enabled rational engineering of the microenvironment around the catalysts to afford activity and selectivity not possible with conventional catalysts.
Surface-Cross-Linked Micelles as Multifunctionalized Organic Nanoparticles for Controlled Release, Light Harvesting, and Catalysis
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Yan Zhao received his B.S. in chemistry from Lanzhou University in 1992 and his Ph.D. from Northwestern University in 1996 (Prof. Joseph B. Lambert). After a postdoctoral stay at the University of Illinois (Prof. Steven C. Zimmerman), he worked for the Procter & Gamble Company from 1998 to 2002 and is currently a professor of chemistry at Iowa State University. His areas of interest include the synthesis of molecules capable of controllable conformational changes and their use as “smart” sensors, materials, molecular transporters, and catalysts; self-assembly in water; biomimetic chemistry in materials synthesis and catalysis; and the design and construction of nanoscale structures.
/////Surface-Cross-Linked Micelles, Multifunctionalized , Organic Nanoparticles , Controlled Release, Light Harvesting, Catalysis