Figure 4. An illustration of targeted delivery of photoimmunotheranostic agent to specifically detect and kill cancer cells.

(1) The SNAP-tag antibody photoimmunoconjugate first binds to the cognate receptor expressed on targeted cancer cells. (2 and 3). Thereafter the APC is internalized through receptor mediated endocytosis into the cell and trafficked to the lysosome. (4) The APC is subsequently exposed to a specific wavelength of light which enables fluorescent based detection of the targeted cell. (5) Irradiation of the APC with a different therapeutic wavelength in the presence of molecular oxygen causes reactive oxygen species (ROS) production which oxidatively damage the cell and induce cell death.