Facile access to internally functionalized dendrimers through efficient and orthogonal click reactions.

A simple synthetic strategy has been developed for accessing internally functionalized dendrimers. The key feature of this approach is the use of two orthogonal and efficient reactions--'epoxy-amine' and 'thiol-ene' coupling--for rapid growth of the dendritic scaffold. This sequence of reactions allows for the introduction of reactive hydroxyl groups at each dendritic layer.

Synthesis and characterization of core-shell star copolymers for in vivo PET imaging applications.

The synthesis of core-shell star copolymers via living free radical polymerization provides a convenient route to three-dimensional nanostructures having a poly(ethylene glycol) outer shell, a hydrophilic inner shell bearing reactive functional groups, and a central hydrophobic core. By starting with well-defined linear diblock copolymers, the thickness of each layer, overall size/molecular weight, and the number of internal reactive functional groups can be controlled accurately, permitting detailed structure/performance information to be obtained. Functionalization of these polymeric nanoparticles with a DOTA-ligand capable of chelating radioactive (64)Cu nuclei enabled the biodistribution and in vivo positron emission tomography (PET) imaging of these materials to be studied and correlated directly to the initial structure. Results indicate that nanoparticles with increasing PEG shell thickness show increased blood circulation and low accumulation in excretory organs, suggesting application as in vivo carriers for imaging, targeting, and therapeutic groups.

Multivalent, bifunctional dendrimers prepared by click chemistry.

Unsymmetrical dendrimers, containing both mannose binding units and coumarin fluorescent units, have been prepared using click chemistry and shown to be highly efficient, dual-purpose recognition/detection agents for the inhibition of hemagglutination.