A facile preparation of targetable pH-sensitive polymeric nanocarriers with encapsulated magnetic nanoparticles for controlled drug release

Novel multifunctional nanocomposites were successfully prepared for the controlled release of anticancer drug and magnetic resonance imaging (MRI) via a simple self-assembly process. In this strategy, superparamagnetic iron oxide nanoparticles (SPIONPs) were fixed between the hydrophobic segment of the pH-sensitive amphiphilic polymer (HAMAFA-b-DBAM) and the surface of hollow mesoporous silica nanoparticles (HMS) which were modified by the long-chain hydrocarbon octadecyltrimethoxysilane (C18). Since the amphiphilic polymer was conjugated with a folic acid (FA) group, the nanocomposites could target the folic acid receptor (FR) of over-expressed tumor cells efficiently. Moreover, high drug loading content was obtained simultaneously due to the hollow core of HMS. The loaded drug could release from the HMS core triggered by the mildly acidic pH environment in the cancer cells due to the hydrolysis of the pH-sensitive polymer shell. The targeting process of the nanocomposites could be easily tracked by MRI due to the magnetism of the SPIONPs. Therefore, a nanocarrier with high drug-loading capacity and controlled drug release property for tumor diagnosis and therapy was obtained via the self-assembly of HMS core, magnetic Fe3O4 nanoparticles and targetable pH-sensitive polymer shell.