Paclitaxel/gelatin coated magnetic mesoporous silica nanoparticles: Preparation and antitumor efficacy in vivo

We reported a magnetic targeted drug delivery system based on core/shell structural magnetic mesoporous silica nanoparticles (MMSNs) and the surface of MMSNs was coated by gelatin layer. In this system, the gelatin layer retarded the diffusion of paclitaxel (PTX, model drug) from quickly moving into the bulk solution to achieve sustained release of PTX. In addition, glutaraldehyde (GA) was used as crosslinking agent to crosslink the coating layer and the release of PTX could be regulated by adjusting the degree of crosslinking of the gelatin layer. The gelatin coated MMSNs (MMSN@GELs) had a saturated magnetization of 5.53   emu/g and could facilely response to an external magnet. To confirm our hypothesis that the carriers could be guided by an external magnetic field in vivo, the ex vivo imaging study and quantitative analysis were conducted. The results reflected that the external magnet altered the biodistribution of the magnetic carriers, so that more magnetic carriers were found to accumulate in tumors rather than to accumulate in normal tissues. Moreover, tumor reduction study reflected that the tumor growth of the group treated with PTX/MMSN@GELs in the presence of an external magnetic field were significantly delayed without an obvious body weight loss compared with PTX/MMSN@GELs in the absence of the magnet and with the commercial Taxol® at the same dose. All the results suggested that MMSNs coated by gelatin would be promising drug carriers for effective delivery of chemotherapeutic agents.