Magnetic mesoporous silica microspheres with thermo-sensitive polymer shell for controlled drug release

Abstract

A controlled drug release system was designed based on the combination of three advantages into one entity, which was composed of Fe₃O₄ magnetic nanoparticle as the core, mesoporous silica as the sandwiched layer, and thermo-sensitive P(NIPAM-co-NHMA) copolymer as the outer shell. The hydrophilic comonomer content affected the volume phase-transition temperature (VPTT) of this composite microsphere and the behavior of the temperature-triggered drug release. Zn(II) phthalocyanine tetrasulfonic acid (ZnPcS₄), a well-known photodynamic therapy (PDT) drug, was used as a model drug to assess the release system. The results demonstrated that the drug release behavior was dependent on the temperature and had a close correlation with the VPTT. Above the VPTT, the drug release rate was much faster than that below the VPTT, which showed a great potential application in tumor therapy.