LAUSR

BACKGROUND A novel pH-sensitive superparamagnetic drug delivery system was developed based on quercetin loaded hyperbranched polyamidoamine-b-polyethylene glycol-folic acid modified Fe3O4 nanoparticles (Fe3O4@PAMAM-b-PEG-FA). The nanoparticles exhibit excellent water dispersity with well-defined size distribution (around 51.8 nm) and strong magnetisability. METHODS In vitro release studies demonstrated that the quercetin-loaded Fe3O4@PAMAM-b-PEG-FA nanoparticles are stable at normal physiologic conditions (pH 7.4 and 37 ˚C) but sensitive to acidic conditions (pH 5.6 and 37 ˚C), which led to rapid release of the loaded drug. RESULTS Fluorescent microscope results indicated that the Fe3O4@PAMAM-b-PEG-FA nanoparticles could be efficiently accumulated in tumor tissue compared with non-folate conjugated nanoparticles. Also, in comparison with free quercetin, the quercetin loaded Fe3O4@PAMAM-b-PEG-FA exerts higher cytotoxicity. CONCLUSION Furthermore, this magnetic nanocarrier showed high MRI sensitivity, even in its lower iron content. The results indicated that the prepared nanoparticles are an effective chemotherapy and diagnosis system to inhibit proliferation and monitor the progression of tumor cells, respectively.