Polymeric micelle-coated mesoporous silica nanoparticle for enhanced fluorescent imaging and pH-responsive drug delivery

Can micelles be served as gating agents and fluorescent labels? Can a drug delivery system be constructed by combining two kinds of drug carriers, such as mesoporous silica nanoparticles and micelles? Will the combination be better or worse? To settle these questions, we designed and constructed a nanocarrier by cooperating two kinds of drug carriers (mesoporous silica nanoparticles and F127 micelles), providing a suitable method for the design of multifunctional stimuli-responsive drug delivery and self-fluorescent imaging systems. The system is fabricated using anticancer drug (curcumin) loaded micelles (CF127) as gating agents and fluorescent labels of mesoporous silica nanoparticles via Schiff base. Because of the pH-sensitive Schiff base, the gating micelles can achieve drug release under acidic condition, while preventing the drug release under natural condition. Moreover, due to the aggregation of CF127 micelles on the surface of mesoporous silica nanoparticles, the fluorescent intensity of CF127 micelles is significantly enhanced. Furthermore, CF127 micelles exhibit good anti-photobleaching property, indicating that the system here is promising for noninvasive in vivo tracking the delivery of therapeutic agents. The cooperation of two kinds of drugs in anti-cancer application and the easily further modification ability of the system is also be confirmed. These results indicate that this study paves the way for a generation of drug delivery systems and could provide a general route to prepare multifunctional biocompatible platforms for biomedical imaging diagnosis and simultaneous therapy for lesion sites such as cancers. (C) 2015 Elsevier B.V. All rights reserved.