Poly(N-isopropylacrylamide)-coated luminescent/magnetic silica microspheres:: Preparation, characterization, and biomedical applications

Smart microstructures based on organic/ inorganic hybrids were rationally designed to develop applications in the novel interdisciplinary research field " nanobioscience". These multifunctional microspheres, combining several advances of photoluminescence and magnetic and temperature responses into one single entity, have been prepared via three steps. The first step involved magnetite nanoparticles ( Fe3O4) homogeneously incorporated into silica spheres using the modified Stober method. Second, metal ions ( Cd2+) were utilized to precipitate the differently sized thiol-capped CdTe nanocrystals onto the Fe3O4- dotted silica surface with negative charges, and then a thin silica shell was coated on them in favor of formation of a robust platform provided for anticorrosion of quantum dots. Third, the modified silica- coated Fe3O4@ SiO2@ CdTe microspheres were covered with the outer shell of thermosensitive poly( N- isopropylacrylamide) via template polymerization. These hybrid microspheres are desired as carriers for diagnostics, circulating drug- delivery systems, and treating cancer at its earliest stages.