Development of dual-function microbeads embedded with quantum dots and iron oxide nanocrystals for biomedical applications

Nanomaterials, such as semiconductor Quantum Dots (QD) and Iron Oxide nanocrystals possess unique properties that are not available in their bulk phase. Some of these properties include the narrow emission spectra, superior brightness and higher photostability of QDs, and the superparamagnetic properties of Iron Oxide nanocrystals. In the past decade, these two nanomaterials have separately seen widespread use in a variety of biomedical applications ranging from multiplexed biomolecular detection to isolation and magnetic manipulation of disease cells and molecules respectively. Here, we describe a method for combining QDs and Iron Oxide nanocrystals into a micron-sized host material in a rapid fashion. The resulting beads are dual functional, i.e. they are optically encoded, and can be manipulated with a permanent magnet. The beads have great potential in biomedical applications because of the combined ability to enrich and detect multiple target molecules from heterogeneous and diluted biological samples. The development of multifunctional composite materials by combining novel nanomaterials is bound to open avenues for ultrasensitive and quantitative bioassays.