Luminescent CdSe Quantum Dot Doped Stabilized Micelles

A general method was developed to prepare siloxane surfactant C 16 H 33 −N + (Me) 2 −CH 2 CH 2 CH 2 −Si(OMe) 3 Cl - micelles doped with highly luminescent lipophilic semiconductor CdSe quantum dots (QDs). Encapsulated green emission CdSe QDs with an emission maximum at 525 nm and red emission QDs with an emission maximum at 650 nm show absorption and emission spectra similar to free CdSe QDs capped by trioctylphosphine oxide (TOPO). Transmission electron microscopy images reveal that the luminescent micelles range from 50 nm to 130 nm in diameter. Each micelle contains over 100 QDs, which significantly increases the emission signal of the composite nanostructure compared to individual QDs. This signal increase enables quantitative luminescence measurements of the QDs using conventional fluorescence microscopes and nonintensified CCD imaging systems, thus making the QD-doped micelles valuable tools in cellular imaging applications. Hydrolysis of the organosilane headgroup of the surfactant forms a silica layer on the surface of QD-doped micelles, which increases the stability of the micelles compared to ordinary surfactant micelles.