Figure 1.
Schematic illustration of nanotheranostics. A nanotheranostic agent is a single entity with three characteristics: nano-sized particle, therapeutic agent, and diagnostic agent. As nano-sized particles, nanotheranostics help to solubilize and protect cargos, improve accumulation of both contrast and therapeutic agents at the disease site, and enable integration of multiple functions into one single particle. As therapeutic agents, nanotheranostics can eradicate cancer cells via singlet oxygen (1O2) or ROS generation, hyperthermia, radiation, or the release of chemotherapeutics. As diagnostic agents, nanotheranostics provide contrast for positron emission tomography (PET), magnetic resonance imaging (MRI), absorbance imaging, fluorescence imaging, or photoacoustic tomography. Nanotheranostics that exert a therapeutic effect upon light irradiation (red) were termed as light-triggered nanotheranostics or LTNs, which are the focus of this review.