Multifunctional Magnetized Porous Silica Covered with Poly(2-dimethylaminoethyl methacrylate) for pH Controllable Drug Release and Magnetic Resonance Imaging

The authors described a smart magnetic-targeting drug carrier γ-Fe2O3@SiO2–PDMAEMA consisting of γ-Fe2O3 and coated with porous silica, further modified by poly(2-dimethylaminoethyl methacrylate). In this research, the porous silica was first coated with poly(2-dimethyl-aminoethyl methacrylate). The material can be loaded with up to 79 mg g–1 of Doxorubicin (DOX) and 90 mg g–1 of rhodamine B (RhoB) (acting as a model drug), which are both greatly larger than reported materials. Cytotoxicity experiments indicated the biocompatibility of γ-Fe2O3@SiO2–PDMAEMA, which is beneficial as drug carriers. DOX and RhoB were both released rapidly at pH 5.5 but the drug release strongly decreased at pH 7.4. The γ-Fe2O3@SiO2–PDMAEMA showed an excellent pH-triggered drug release. The possibility of the particles in magnetic resonance imaging (MRI) was discussed and the significant dose-dependent contrast enhancement in T2-weighted MRI suggested that γ-Fe2O3@SiO2–PDMAEMA can be potentially applied in T2 MRI. The fluorescence imaging of γ-Fe2O3@SiO2–PDMAEMA loaded with RhoB proved the particles can be taken up by cells. All the results exhibited a promising application in safe cancer therapy.