Polymer hybrid magnetic nanocapsules encapsulating IR820 and PTX for external magnetic field-guided tumor targeting and multifunctional theranostics.

Developing multifunctional nanoparticle-based theranostic systems for personalized cancer diagnosis and treatment is highly desirable. Herein, a magnetic targeting theranostic nanocapsule (NC-SPIOs-IR820-PTX) was fabricated by hierarchically assembling superparamagnetic iron oxide nanoparticles (SPIOs), cyanine dye (IR820) and chemotherapeutic compound of paclitaxel (PTX) with poly(ε-caprolactone-co-lactide)-b-poly(ethylene glycol)-b-poly(ε-caprolactone-co-lactide) (PCLA-PEG-PCLA). The nanocapsules exhibited high stability and biocompatibility both in vitro and in vivo. The nanocomposites maintained their morphology in the cellular uptake and showed efficient tumoricidal activity. Most importantly, the external magnetic field could remotely control the nanocapsules and guide them to target tumors for magnetic resonance imaging (MRI)/near-infrared (NIR) fluorescence imaging. The synergistic therapeutic effects of NC-SPIOs-IR820-PTX with extra-magnetic field-induced tumor targeting ability have enhanced the co-therapy of photo-chemotherapy, resulting in significant tumor inhibition effects. Therefore, NC-SPIOs-IR820-PTX theranostics could be applied for magnetic field guided tumor targeting as well as multimodal MRI/NIR imaging, and imaging-guided combined therapy.