Synthesis of Multifunctional Fe3O4@mSiO2@Au Core-Shell Nanocomposites for pH-Responsive Drug Delivery

A multifunctional nanocomposite has been successfully prepared for pH-responsive and magnetic-targeting drug delivery. First, Fe3O4@mesoporous silic (mSiO(2)) core-shell nanoparticles were synthesized as the nanocapsules. Doxorubicin hydrochloride was adopted as the model drug; after drug loading, gold nanoparticles (5 nm) were connected to block the mesopore through the hydrazone linkage. The hydrazone bond, a typical acid-sensitive bond, could undergo hydrolysis in an acidic environment to induce the release of the capping agent, so that the multifunctional nanocomposite revealed acid-enhanced release performance. What's more, before reaching acid conditions, little premature release was found to take place. Cell experiments were also carried out to reveal the good biocompatibility, fast uptake, and improved toxicity toward HeLa cells. Thus, in association with the magnetic target, the multifunctional nanocomposite shows the potential application for some low-pH tissue-targeted therapy, such as for inflammation and tumors.