The utilization of multifunctional organic dye with aggregation-induced emission feature to fabricate luminescent mesoporous silica nanoparticles based polymeric composites for controlled drug delivery

Aggregation-induced emission (AIE) is an abnormal fluorescence phenomenon and various AIE-active molecules and materials have been reported previously. In this work, a novel multifunctional AIE-active molecule 10-phenylphenothiazine (Ph-PTZ) has been synthesized and incorporated into mesoporous silica nanoparticles (MSNs) to form luminescent MSNs. The Ph-PTZ was used as catalyst for metal-free photocatalytic atom transfer radical polymerization (ATRP) to generate copolymers on the surface of these luminescent MSNs under light irradiation using poly(ethylene glycol)methyl acrylate (PEGMA) and itaconic acid (IA) as monomers. The introduction of copolymers could not only improve the aqueous stability of composites, but also could endow the capability for loading the anticancer agent cis-diammineplatinum dichloride (CDDP). The successful fabrication of PTH@MSNs-poly(PEGMA-co-IA) composites was confirmed by various characterization techniques. We demonstrated that PTH@MSNs-poly(PEGMA-co-IA) composites show high water dispersibility, low toxicity and are promising for biological imaging. Moreover, CDDP can be effectively loaded on PTH@MSNs-poly(PEGMA-co-IA) and controlled release it from the PTH@MSNs-poly(PEGMA-co-IA)-CDDP complexes with pH responsive behavior. Taken together, we have fabricated the luminescent polymeric MSNs composites with great potential for biological imaging and controlled drug delivery through self-photocatalytic ATRP. This work is of great research interest for fabrication of many other multifunctional luminescent polymeric composites owing to the obvious advantages of self-photocatalytic ATRP.