Figure 1.

Representative examples of molecules utilized for photoacoustic purposes, that are described in this review. (a) Photoacoustic imaging (PAI) probes, (b) “classic” theranostics consisting of a drug and a dye tethered through various linkers, (c) targeted theranostic agents utilizing a tumor-homing element, and (d) theranostics utilized for simultaneous PAI and phototherapy. Photoacoustic agents are colored black, drugs are colored in light blue, targeting moieties are colored in green, the trigger group is colored in purple, and linkers are colored in red. PAI = Photo acoustic imaging; PTT = Photothermal therapy; PDT = Photodynamic therapy. Some of the illustrated components might have a dual role (e.g., indocyanine green dye analogs shown in black color in (c) offer both imaging and therapeutic properties).