One-pot construction of doxorubicin conjugated magnetic silica nanoparticles

Doxorubicin (DOX) conjugated magnetic silica nanoparticles (DOX-Fe ₃O₄-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 (-NCO) 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 Fe₃O ₄/SiO₂ nanoparticles would foster innovative avenues for the development of smart drug delivery and controlled release systems.