Dual docetaxel/superparamagnetic iron oxide loaded nanoparticles for both targeting magnetic resonance imaging and cancer therapy

Theragnostics polymer nanoparticles (NPs) loaded simultaneously with anticancer drug docetaxel (Dtxl) and superparamagnetic iron oxide (SPIO) nanocrystals were developed for both cancer therapy and ultrasensitive MRI. These multifunctional polymer vesicles were formed by carboxy-terminated poly(lactic-co-glycolic) acid using a single emulsion evaporation method. The active tumor-targeting single chain prostate stem cell antigen antibodies (scAb(PSCA)) were conjugated on the surface of polymer vesicles by using functional poly(ethylene glycol). The diameter of NPs was about 147 nm and the SPIO and drug encapsulation efficacy was 23% and 6.02%, respectively. Vibration simple magnetometer and X-ray diffraction proved that the superparamagnetic behavior of SPIO was not changed during NPs formation and modification. The NPs exhibited a triphasic drug release pattern in vitro over 30 days. Enhanced cellular uptake ability and antiproliferative effect of the targeted NPs in prostate cancer PC3 cell line by using the confocal laser scanning microscopy and cytotoxicity assay were observed. Moreover, the Prussian blue staining and the MRI assay in vitro demonstrated that the NPs have a high SPIO clustering effect. Therefore, these stable and tumor-targeting polymer NPs could be promising multifunctional vesicles for simultaneous targeting imaging, drug delivery and real time monitoring of therapeutic effect. (C) 2011 Elsevier Ltd. All rights reserved.