Cyanine-Containing Polymeric Nanoparticles with Imaging/Therapy-Switchable Capability for Mitochondria-Targeted Cancer Theranostics

Theranostic nanoparticles (NPs) capable of mitochondrial targeting/imaging, cancer/normal cell differentiation, early stage cancer diagnosis, and mitochondria-based photothermal therapy (PTT) were developed. The NPs were fabricated by physical encapsulation of near-infrared (NIR) heptamethine cyanine dye me-IR825 into the inner core of the micelle-forming copolymer Pluronic F127 (PF127). The PF127/me-IR825 NPs exhibited two fluorescence emissions at ∼610 nm (excited by 550 nm) and 845 nm (excited by 780 nm). The former was used for in vitro mitochondrial fluorescence imaging, cancer/normal cell differentiation, and early stage cancer detection with high fluorescence contrast. The latter was used for in vivo NIR fluorescence imaging. Besides, the NPs could also be used for in vivo photoacoustic imaging under 808 nm excitation. After irradiation by an 808 nm laser at an elevated power density, the NPs achieved excellent photothermal tumor ablation both in vitro and in vivo. Furthermore, me-IR825 inside the inner core of PF127/me-IR825 NPs could be degraded into biocompatible products after PTT treatment, which guaranteed the post-treatment biosafety of the NPs. Benefiting from their simple preparation, good colloidal dispersibility/stability, excellent cancer/normal cell differentiation ability, and superb in vivo dual-modal imaging-guided therapeutic outcome, the PF127/me-IR825 NPs may be used as a theranostic nanoplatform for applications in the biomedical field.