Chemical template-assisted synthesis of monodisperse rattle-type Fe₃O₄@C hollow microspheres as drug carrier.

Abstract

A chemical template strategy was put forward to synthesize monodisperse rattle-type magnetic carbon (Fe₃O₄@C) hollow microspheres. During the synthesis procedure, monodisperse Fe₂O₃ microspheres were used as chemical template, which released Fe³⁺ ions in acidic solution and initiated the in-situ polymerization of pyrrole into polypyrrole (PPy) shell. With the continual acidic etching of Fe₂O₃ microspheres, rattle-type Fe₂O₃@PPy microspheres were generated with the cavity appearing between the PPy shell and left Fe₂O₃ core, which were then transformed into Fe₃O₄@C hollow microspheres through calcination in nitrogen atmosphere. Compared with traditional physical template, the shell and cavity of rattle-type hollow microspheres were generated in one step using the chemical template method, which obviously saved the complex procedures including the coating and removal of middle shells. The experimental results exhibited that the rattle-type Fe₃O₄@C hollow microspheres with different parameters could be regulated through controlled synthesis of the intermediate Fe₂O₃@PPy product. Moreover, when the rattle-type Fe₃O₄@C hollow microspheres were investigated as drug carrier, they manifested sustained-release behaviour of doxorubicin, justifying their promising applications as carriers in drug delivery. The aim of the present study was first to synthesize rattle-type Fe₃O₄@C hollow microspheres through a simple synthesis method as a drug carrier. Here a chemical template synthesis of rattle-type hollow microspheres was developed, which saved the complex procedures including the coating and removal of middle shells in traditional physical template. Second, all the influence factors in the reaction processes were systematically investigated to obtain rattle-type Fe₃O₄@C hollow microspheres with controlled parameters. Third, the rattle-type Fe₃O₄@C hollow microspheres were studied as drug carriers and the influences of their structural parameters on drug loading and releasing performance were investigated.