Water-dispersible, multifunctional, magnetic, luminescent silica-encapsulated composite nanotubes

A multifunctional one-dimensional nanostructure incorporating both CdSe quantum dots (QDs) and Fe₃O₄ nanoparticles (NPs) within a SiO_2- nanotube matrix is successfully synthesized based on the self-assembly of preformed functional NPs, allowing for control over the size and amount of NPs contained within the composite nanostructures. This specific nanostructure is distinctive because both the favorable photoluminescent and magnetic properties of QD and NP building blocks are incorporated and retained within the final silica-based composite, thus rendering it susceptible to both magnetic guidance and optical tracking. Moreover, the resulting hydrophilic nanocomposites are found to easily enter into the interiors of HeLa cells without damage, thereby highlighting their capability not only as fluorescent probes but also as possible drug-delivery vehicles of interest in nanobiotechnology.