Shell-sheddable and charge switchable magnetic nanoparticle as pH-sensitive nanocarrier for targeted drug delivery applications

A pH-sensitive shell-sheddable magnetic nanocarrier was prepared based on Fe3O4@SiO2 nanoparticles coated with polyethyleneimine (PEI) and polyethyleneglycol (PEG). The PEI was coated on Fe3O4@SiO2 nanoparticles through an electrostatic attraction and the PEG chains were connected to the PEI via pH-sensitive benzoic-imine bonds. The synthesized products and final nanocarrier were characterized with FT-IR, 1H NMR, dynamic light scattering (DLS), zeta-potential, TEM, and vibrating-sample magnetometer (VSM). The PEI, as a middle layer, was used to load the curcumin (an anticancer drug) via van der Waals interactions and the shedding of PEG as a hydrophilic corona at the tumor pH (acidic) could induce the release of the drug. The curcumin loading content was found to be ~15% and curcumin-loaded magnetic nanoparticles (C-LMNs) showed more triggered release at the tumor pH (5.6) than physiological pH (7.4). In comparison to pure magnetic nanoparticles (MNs), the C-LMNs showed more cytotoxicity to human prostate cancer cell (PC-3) and also resulted in an increased rate of late apoptotic/necrotic PC-3 cells, assessed by flow cytometry analysis. In conclusion, the C-LMN as pH- and magnetic responsive nanocarrier showed good potential for targeted curcumin delivery in therapy of prostate cancer.