Doping mesoporous materials with multicolor quantum dots

Rapid and precise doping of mesoporous silica beads has been achieved with luminescent quantum dots, leading to 1-2 orders of magnitude improvements over the results previously achieved with polystyrene latex beads. A surprising finding is that multivalent hydrophobic interactions provide a strong driving force for efficient partitioning and immobilization of surfactant-coated quantum dots in the silica nanopores. The results indicate that the doping levels are so quantitative and precise that at least 30 ratios are distinguishable with two colors of quantum dots and that over 1000 ratios are possible with only three colors. By integrating mesoporous structures and quantum-confined particles, this work opens new possibilities in developing encoded or "smart" nanocomposite materials for multiplexed bioassay, high-throughput screening, and military security applications.