One-pot construction of doxorubicin conjugated magnetic silica nanoparticles

Doxorubicin (DOX) conjugated magnetic silica nanoparticles (DOX-Fe3O4-SiO2) are successfully fabricated using a new one-pot method without need for the process of inconvenient multistep synthesis in advance, based on the condensation of DOX and the silica precursor 3-isocyanatopropyltriethoxysilane (ICPTES), followed by the spontaneous formation of a silica coating onto the surface of Fe3O4 nanoparticles via sol-gel polymerization of triethoxysilane. Mass spectroscopy provides evidence that doxorubicin is conjugated to ICPTES via a urea bond (-NHCONH-) via the reaction of the amino groups of DOX with the isocyanate group (-N=C=O) of ICPTES in water. The obtained magnetic nanoparticles are well dispersed. Their mean diameter is about 66.9 nm with a narrow size distribution. The conjugated DOX-SiO2-Fe3O4 nanoparticles exhibited a higher loading efficiency of 60.5 +/- 3.7% and a more sustained release profile than SiO2 nanoparticles containing physically-entrapped DOX. It is anticipated that fine-tuning of other drugs or bioactive molecules containing -NH2 groups to Fe3O4/SiO2 nanoparticles would foster innovative avenues for the development of smart drug delivery and controlled release systems.