Synthesis and Characterization of a Poly(amido amine) Modified Magnetic Nanocarrier for Controlled Delivery of Doxorubicin

We prepared a magnetic poly(amido amine) (G2.5)-hydrazine hydrate nanocarrier, denoted by MNPs@PAMAM-H. PAMAM dendrimer was conjugated onto the surface of magnetic nanoparticles (MNPs) to increase the biocompatibility of the nanocarrier and provided a large number of reactive sites for coupling of drug molecules. DOX was covalently attached to the nanocarrier via a pH-sensitive linker, hydrazone bond, which hydrolyzes in the acidic lysosomal environment to allow pH-sensitive release of DOX. DOX was successfully loaded into the nanocarrier with a high drug loading (27.53%) and entrapment efficiency (86.44%). Nearly 88% DOX was released within 60 h at pH 5.0, compared with only 30% at pH 7.4. The in vitro MTT assay in HeLa cells demonstrated that MNPs@PAMAM-DOX exhibited high anti-tumor activity, while the MNPs@PAMAM-H were practically non-toxic. These results revealed that MNPs@PAMAM-H were biocompatible. The Synthesized nanocarrier had the potential to be used as MR probe and guide DOX to enter target sites in cancer therapy by an outer magnet.