Theranostic micelles combined with multiple strategies to effectively overcome multidrug resistance.

Aim: To develop precise targeting and versatile Fe3O4@SiO2-P123/PTX-ZnPc nanoparticles (FSP-PTX-ZnPc NPs) to reverse paclitaxel (PTX)-induced multidrug resistance in breast cancer. Materials & methods: PTX and zinc (II) phthalocyanine (ZnPc) co-loaded FSP-PTX-ZnPc NPs were designed. The resulting multifunctional NPs were evaluated systematically in vitro and in vivo, and the mechanism of drug-resistance reversal was investigated. Results: The NPs enhanced drug uptake in MCF-7/PDR cells by increasing drug solubility and impairing P-glycoprotein efflux. Additionally, magnetic targeting and enhanced permeation and retention (EPR) effect enhanced drug accumulation in tumor, facilitating the chemotherapeutic and photodynamic therapy effects. Moreover, FSP-PTX-ZnPc NPs could penetrate the blood-brain barrier, a desirable trait for brain disease therapy. Conclusion: The multifunctional FSP-PTX-ZnPc NPs are an effective tool for overcoming drug resistance in breast cancer.