Intracellular pH-responsive polymeric micelle for simultaneous chemotherapy and MR imaging of hepatocellular carcinoma

Theranostic nanosystem has been demonstrated great potential in real-timely monitoring drug biodistribution and therapeutic response. It is still a challenge to fabricate a theranostic nanosystem that possesses the properties of good biocompatibility, a high magnetic resonance imaging (MRI) sensitivity, and stimuli-responsive drug release for the diagnosis and treatment of hepatocellular carcinoma. Here, a pH-responsive micelle, which was self-assembled from biodegradable poly(amino acid) block copolymer mPEG-PAsp(DIP)-co-PLLeu, was constructed to load both chemotherapeutic paclitaxel (PTX) and MRI contrast agent superparamagnetic iron oxide nanoparticles (SPIONs). The SPIONs/PTX-coloaded PDPL micelle (SPIONs/PTX-PDPL) had a hydrodynamic particle size of 134.5 +/- 11.2 nm. The theranostic SPIONs/PTX-PDPL not only effectively delivered PTX and SPION into Bel-7402 cancer cells but also rapidly released PTX in acidic lysosome to induce cell apoptosis. Meanwhile, in vitro MR imaging sensitively detected the liver cancer cells after co-incubation with SPIONs/PTX-PDPL micelle. The SPIONs/PTX-PDPL micelle is a potential theranostic nanosystem in terms of the simultaneous chemotherapy and MR imaging of hepatocellular carcinoma.