Fluorescent Quantum Dot−Polymer Nanocomposite Particles by Emulsification/Solvent Evaporation

CdSe/ZnS quantum dots (QDs) were incorporated into biocompatible polyisoprene (PI) particles by microencapsulation through emulsification/solvent evaporation, a technique that is facile, robust, and inexpensive. Emulsification/solvent evaporation results in QDs encapsulated into the particle core without requiring chemical modification of the as-prepared QDs. The PI can be easily cross-linked after encapsulation to enhance the fluorescence stability of the QDs. The resulting PI−QD nanocomposite particles form as colloidally stable suspensions in water that exhibit stable fluorescence for months. The surface of the PI−QD nanocomposite particles was functionalized with carboxylates during the QD encapsulation to facilitate subsequent bioconjugation. Streptavidin-coated PI−QD particles displayed selective binding to biotin-conjugated polystyrene spheres, thus demonstrating the potential application of these particles in biolabeling.