A rod bacterium-like magnetic polymer micelle for strongly enhancing selective accumulation and internalization of nanocarriers

The precise and highly efficient delivery of a therapeutic agent with nanocarriers to a tumor site to achieve excellent therapeutic efficacy remains a major challenge in cancer chemotherapy. Here, we present a multifunctional rod bacterium-like polymer micelle with both magnetic-guided and active-targeted abilities. This micelle is formed by self-assembly of phenylboronic acid (PBA) functionalized copolymer in a sodium chloride water solution, in which the anticancer drug doxorubicin (DOX) and magnetic nanoparticles Fe3O4 are simultaneously loaded. The rod-like architecture with a diameter ∼20 nm and length ∼600 nm has a great capacity to prolong the blood circulation of the nanocarriers with a circulation half-life of more than 24 hours and to enhance cellular internalization. The magnetic nanoparticles in the micelles can not only precisely guide the nanocarriers and enhance the accumulation of these nanocarriers in the tumor site by the application of an external magnetic-field, but they can also improve the contrast difference between polymer micelles and cell compartments for evaluating the nanocarriers' distribution. The PBA targeting ligands endow the nanocarriers with active targeting, resulting in a selective recognition and a resultant endocytosis of salic acid-positive tumor cells. The in vivo antitumor effect displays that the nanocarrier has excellent inhibiting potency against tumor growth, with an 83% inhibition rate in an H22 hepatocarcinoma cells tumor model. These findings suggest that this rod-like magnetic polymer micelle has great promise for addressing current limitations in anticancer drug delivery against cancerous diseases.