Surface functionalization of magnetic mesoporous silica nanoparticles for controlled drug release

The modified sol-gel approach to the synthesis of well-structured magnetic mesoporous silica nanoparticles (M-MSNs) was described, which comprised magnetic nanoparticles resided within the mesoporous nanoparticles. A diversity of surface modification was subjected to systematic investigation using organic silanes, eventually resulting in the decoration with the carboxyl (-COOH), methyl phosphonate (-PO(3)(-)), amino (-NH(2)) and phenyl (-Ph) groups on the surface of M-MSNs. The careful characterizations demonstrated that the modified M-MSNs displayed the specifically charged surfaces and differently porous characters, yet without showing any influence on the shape and size. To exploit their potential in cancer treatment, we extensively studied the drug loading capacity and sustained release behaviour of the modified M-MSNs for representative drugs. The hydrophilically modified M-MSNs with -COOH and -PO(3)(-) were beneficial for loading the water-soluble doxorubicin hydrochloride (DOX) through electrostatic attraction. The results demonstrated that M-MSNs-PO(3)(-) achieved a higher loading content and M-MSNs-COOH presented a distinct pH-responsible release behavior. On the other hand, M-MSNs-Ph displayed a controlled release rate in a short term via the weakened hydrogen bonding interaction. The cytotoxicity of modified M-MSNs to normal cells and macrophage uptake indicated that the modified M-MSNs were suitable as drug carriers. These mesoporous nanoparticles were non-toxicity to HeLa cells, while the drug-loaded nanoparticles apparently led to the unambiguous cytotoxicity as a result of the sustained release of drugs. These results have an important implication that the modified M-MSNs are promising as platforms for storing the hydrophilic or hydrophobic anticancer drugs for tumour therapy.