Prostate cancer-specific thermo-responsive polymer-coated iron oxide nanoparticles.

Thermo-responsive poly(N-isopropylacrylamide-acrylamide-allylamine)-coated magnetic nanoparticles (PMNPs) were developed and conjugated with prostate cancer-specific R11 peptides for active targeting and imaging of prostate cancer. The stable nanoparticles with an average diameter of 100 nm and surface charge of -27.0 mV, had a lower critical solution temperature of 40 °C. Magnetic characterization showed that the nanoparticles can be recruited using a magnetic field and possess superparamagnetic behavior even after R11 conjugation. In vitro cell studies demonstrated that R11-conjugated PMNPs (R11-PMNPs) were compatible with human dermal fibroblasts and normal prostate epithelial cells to all tested concentrations up to 500 μg/ml after 24 h of incubation. Moreover, the nanoparticles were taken up by prostate cancer cells (PC3 and LNCaP) in a dose-dependent manner, which was higher in case of R11-PMNPs than PMNPs. Further, in vivo biodistribution of the nanoparticles showed significantly more R11-PMNPs accumulation in tumors than other vital organs unlike PMNPs without R11 conjugation. Moreover, R11-PMNPs decreased 30% magnetic resonance T2 signal intensity in tumors in vivo compared to 0% decrease with PMNPs. These results indicate great potential of R11-PMPs as platform technology to target and monitor prostate cancers for diagnostic and therapeutic applications.