A magnetic polypeptide nanocomposite with pH and near-infrared dual responsiveness for cancer therapy

A magnetic polypeptide nanocomposite with pH and near-infrared (NIR) dual responsiveness was developed as a drug carrier for cancer therapy, which was prepared through the self-assembly of Fe 3 O 4 superparamagnetic nanoparticles, poly(aspartic acid) derivative (mPEG- g -PDAEAIM) and doxorubicin (DOX) in water. Fe 3 O 4 nanoparticles were prepared to provide the superparamagnetic core of nanocomposites for tumor targeting via chemical co-precipitation. The protonable imidazole groups of mPEG- g -PDAEAIM with a pKa of ~7 were accountable for the pH-responsiveness of nanocomposites. The photothermal effect of nanocomposites under the irradiation of NIR laser was induced via the interactions between dopamine groups of mPEG- g -PDAEAIM and Fe 3 O 4 superparamagnetic nanoparticles to trigger the drug release. NMR, FT-IR, TEM, hysteresis loop analysis and MRI were utilized to characterize the materials. The DOX loaded nanocomposites exhibited pH-responsive and NIR dependent on/off switchable release profiles. The nanocomposites without drug loading (Fe 3 O 4 @mPEG- g -PDAEAIM) showed excellent biocompatibility while DOX loaded nanocomposites caused MCF-7 cells’ apoptosis due to the photothermal/chemotherapy combination effects. Overall, the pH and near-infrared dual responsive magnetic nanocomposite had a great potential for cancer therapy.